*H mm{ m The OLIVER PLOW BOOK Paper Bound can be secured as follows: SINGLE COPIES $ 1.00 PER DOZEN 10.00 LARGER QUANTITIES, per doz. . 9.00 COPYRIGHT I 9 2 O BY ED PLOW ' BEND. I N D. 'E R CHI SOUT S. A. IIM A Treatise on Plows and plowinq Published by OliverChiltedPlowVorifs if South bond, Ind, MAR IO1S20 ©CU564710 Preface HE treatment of any farmer's soil is entirely within his hands. Success is measured by his knowledge and the diligence with which he applies those laws of Nature which are related to crop growing. These laws are universal. A farmer can apply them to meet his own partic- ular need better than acting upon the ad- vice anyone can give him, because he understands his soil conditions. Other people do not. The purpose of this book is to set forth these laws and explain the causes and effects. The Oliver Chilled Plow Works has a desire to be of practical value to farmers. Our long experience in building plows and kindred implements for use all over the world has given u$ ai& opportunity to ob- serve a great many facts in connection with plows and plowing which should be common knowledge among farmers. OLIVER CHILLED PLOW WORKS. CONTENTS Chapter Page I. Functions of the Plant Organs 5 II. Influence of Water 14 III. Importance of Air in the Soil 27 IV. Soil Temperature 32 V. Why Soils Must Be Handled Differently 37 VI. Depth of Plowing 51 VII. When to Plow 63 VIII. Plowing to Kill Insects 72 IX. Plowing to Kill Weeds 79 X. Plowing Under Green Manure 87 XI. Judging Plowing 92 XII. Plow Bottoms 97 XIII. Plow Bottom Metals 129 XIV. Scouring Troubles 137 XV. Setting the Share on the Plow 1 49 XVI. Sharpening Soft Center Steel Shares. ... 154 XVII. Sharpening Crucible Steel Shares 158 XVIII. Sharpening Chilled Shares 159 XIX. The Rolling Coulter 160 The Jointer The Combined Rolling Coulter and Jointer XX. The Tractor Plow Hitch 167 XXI. Adjusting Horse Plows 183 XXII. Middle Breakers 189 XXIII. Disk Plows 195 CHAPTER I Functions of the Plant Organs THERE is a vast difference between operating a farm and a factory. The process of manufacture from the receiving of the crude materials to the finished product is entirely in the hands of the manufacturer. That is, he can control every step in any process from start to finish. It is not so with the farmer. The farmer can control only the operation of the machinery. He has to have a partner to enable him to successfully grow crops. That partner is mother Earth. He has to depend upon her for everything except the labor, which is his part of the contract. Obviously the farmer who succeeds best must under- stand Nature. It is a hopeless task to learn all the whims and caprices of Nature, but it is possible to learn how to treat mother Earth so that she can use these whims and caprices of Nature to bring forth bountifully. The first step in this process is plowing. Many important historical events offer the strongest evidence that from the time man first began to till the soil he discovered the necessity for stirring it in some manner before any kind of a crop could be grown. Even the greatest authors of antiquity, medieval and modern times, speak of plowing. We have Benjamin Franklin in our own colonial times who advised farmers "to plow deep while sluggards sleep and you will have corn to sell and keep." Pliny spoke in his treatise on agriculture, THE OLIVER PLOW BOOK of the importance of having the ground properly pre- pared, and even in the New Testament, in the book of St. Luke, the parable of the sower forcibly illustrates that Christ was a keen observer of the laws of Nature as related to crop growing. "A sower went out to sow his seed; and as he sowed some fell by the way side; and it was trodden down, and the fowls of the air devoured it. And some fell upon a rock; and as soon as it was sprung up, it withered away, because it lacked moisture. And some fell among thorns; and the thorns sprang up with it, and choked it. And other fell on good ground, and sprang up, and bare fruit a hundredfold." This quality to observe conditions as they are is just as fundamental to the business success of any man as it is for his religious welfare. There is not such a tremendous amount of difference. Evidently farmers in Christ's time believed that it was necessary to kill the thorns and to conserve moisture, and they believed still more that it was necessary to have the ground "good." This word "good" involves a great deal. Our modern soil phycisists tell us that we plow to kill weeds, conserve moisture, and to put the ground in a good condition of tilth. By tilth they mean that the land is in shape to be cultivated easily and in such condition as to bring forth abundantly. Before one can put ground in condition to meet plant growth requirements he must have a thorough under- standing of the habits and characteristics of plants he desires to grow, the kind of food that plants require and FUNCTIONS OF PLANT ORGANS FRUIT LEAVES A fully matured corn plant showing the parts that have to do with the growth of the plant. Observe the short root system compared with the network of roots of the four hills of growing corn illustrated on page eleven. STEM / Wa ROOTS THE OLIVER PLOW BOOK the soil conditions necessary for the manufacture, maintenance and proper distribution of that food to the plants as they need it. Botanists tell us that every part of the plant has functions which it performs for its own development. The functioning of the various organs of the plant is naturally very different from that of the animal, never- theless, these organs are just as important to the plant as the digestive and breathing organs are to the animal. The greatest of care is exercised in feeding the stock. The proper amount of food and water is given to the animals at the right time. In the summer the green pastures supply the great percentage of food for cows. In the winter they are given foods which produce milk and flesh. If horses are being used in the field they are fed the kind of food that keeps them strong and healthy. The same rule holds true of the entire animal family. No two types of animals ever receive the same kind of food nor even the same portion; that has to be given according to their kind. The same feeding law holds true of plants. Plant life is different from animal life. The animal is either fed by human hands or goes about searching its own food. The plant is stationary. It, therefore, must subsist upon the food contained in the air and soil within reach of its organs. All crop producing plants have roots, stems, leaves, and flowers, or the fruit. The farmer is concerned as to the quality and quantity of fruit produced. The quality and quantity of fruit are determined by the growth of the leaf and stem, and also the plant's ability to withstand the evil influences of wind, drouth and excessive rainfall. FUNCTIONS OF PLANT ORGANS The seed of any plant is supposed to contain enough nourishment for growth until the roots are large enough to drink in their nourishment from the surrounding soil, and the stem to break through the top of the ground to breathe in the required air. The roots are the organs that search out into every particle and recess of the soil within reach for plant food, and carry it to the stem. The most important part of the crop growing opera- tion consists in bringing about a soil condition whereby the seed can germinate according to its natural inclina- tion and the plant produce a root system necessary for vigorous growth and flowering. The little kernels in the wheat illustration were sprouted to show how little and tender are the roots of germinating seeds. Four kernels of sprouted wheat. The two outside kernels would sustain the plant until the roots and stems could feed themselves. The two inside plants were weak seeds. The seeds are entirely consumed, and the young plants are not large enough to support themselves. 10 THE OLIVER PLOW BOOK It is important that a seed bed be in a well pulverized, compact condition for the sprouting of seeds and grow- ing of plants. The little kernels of wheat must sprout and grow, but before they can do it the plant food must be in the soil in available form for the little tender roots to feed upon. Observe the sprouts running up and the little roots going downward. One pinch of the root with the fingers would kill it, yet, it is supposed to grow and produce tenfold times. There is food enough within the kernel, if it is good seed, to nourish the grow- ing plant for a short time, but after that it must reach out into the soil to find sustenance, and if that plant grows rapidly it must have the food within convenient reach just when it needs it. This is the great reason why the preparation of the seed bed is the most im- portant part of the crop growing operation. It matters not how good the seed, if the soil is not in the right con- dition to make plant food available to nourish the starting plant, growth will be stunted. Pulverizing the ground when plowing is the first and most vital step to accomplish this end. There is another reason why a compact seed bed is necessary. After the seed has sprouted, and the plant has acquired its growth, more food is necessary for the flowering of the grain. The roots are searching through the ground by means of their continued growth to find this food. The better pulverized the seed bed is, the more available food the roots find. They form a net- work of food seekers entirely occupying the ground from one plant to another. The corn field illustration, in which the rain has washed away the earth from the roots, shows the interweaving of the root system of corn. Each of the little hair FUNCTIONS OF PLANT ORGANS 1 1 roots drinks in its share of food for the plants. When we consider that plants are soup eaters, that is, all the food the roots absorb is taken in liquid form, the im- portance of having the best possible seed bed from top to bottom is obvious. When the rain washed away the earth it generously left the corn roots in much the same position as they would be found if it were possible to look into the earth. A study of this illustration shows how easy it is to break these roots by cultivation. Recognizing that roots are necessary for absorbing the food contained in the soil, the importance of protecting this root system and giving it every opportunity becomes apparent. The stems are the conveyors of this food to the leaves and the flowers and also serve the important purpose of holding up the flowers and leaves from the ground to give them an opportunity to do their work. The leaf has four principal functions to perform. It has to do with the starch making properties of the plant, 12 THE OLIVER PLOW BOOK the assimilation, the excretion of water, and breathing. The functions of the leaves in these four processes in- volve a very complicated chemical process which is not very thoroughly understood and does not need to be from a practical standpoint. The only thing necessary to know is that a plant, to flower and produce the proper grain, must have an abundance of moisture in order that the sunlight and air may supply the proper gases and heat necessary to bring about these chemical changes. The task of the farmer is to see that air, water and the proper plant food elements are properly proportioned in the soil. He need not worry about the part that surface air plays in the growing of the plants because it is beyond his control. Nature always supplies it abundantly on and above the earth's surface. To be of the utmost value air must be permitted to permeate every particle of the seed bed. The tiller of the soil must see that the proper amount of plant food is supplied during the plant's life so that the entire plant can perform its functions. He must not forget also that a plant, even as any animal, can gorge itself so that one part of it will grow to the detri- ment of another. The plant may be considered in part as its own food manufacturing establishment; that is, certain of the food elements coming from the soil are mingled with the gases which come through the leaves in such a way as to form the starchy substances of the plants. It is vitally necessary, therefore, that both the soil and air supply the proper elements for these processes to take place in the plant. The amount of plant food contained in water is very small, hence, the plant must consume an immense FUNCTIONS OF PLANT ORGANS 13 amount of water to derive the sustenance necessary. A grass plant has been found, to give off its own weight in water every twenty-four hours in hot, dry summer weather. This would make about 6J/2 tons of water per acre for every twenty-four hours in ordinary grain fields. This proves that moisture is one of the most essential items for producing plant growth and must be properly provided. Botanists maintain that 95 to 97 per cent, of all the materials from which Nature builds the tissues of her plants are taken from the air. It is important, then, that we know by what process the materials from the air are transformed into plant food, particularly that part of the process which Nature depends upon tillage and the soil to perform. Nature furnishes the moisture, air, light and soil. She expects us to till the soil in order that she may use the moisture, air, light and soil to the best advantage in transforming materials into plant food for growing crops. She rewards bountifully those who work with her, and she recompenses poorly those who do not. Working with Nature means a knowledge of the effect of moisture, air, light and heat upon the soil and apply- ing that knowledge in a practical manner. CHAPTER II Influence of Water WATER is the greatest single factor in plant growth. It seldom rains at just exactly the right time for its use. The task is to keep this moisture where it can be uti- lized by the growing plants just as rapidly as they need it. Before this can be done successfully one must have a knowledge of the characteristics of the different types of soils, their capacity for holding moisture and the rapidity with which it percolates and evaporates, also the things that are necessary to permit moisture to sink into the ground and keep it from escaping. Water is the solvent of mineral elements in the soil which nourish the plant, and since plants can absorb mineral salts only in solution, water is absolutely nec- essary to enable the plant to take nourishment from the soil. Water is the means whereby plant food elements are transformed into plant food because without it there can be no chemical action or reaction to transform the elements into plant food. Water also holds in solution food for the plant, carries it from the hair roots to the stem, and from the stem to the places where growth is taking place, transports plant food from one place to another in the soil, and is a temperature regulator for the soil. From 75% to 90% of the fresh substance in crops is water, thus water in itself is plant food and essential to INFLUENCE OF WATER 15 plant life. The greater part of this per cent, enters the plants through the roots. The 75% to 90% of water making the fresh substance of plants is water in plant composition, and can only be taken from the plants by excessive heat. However, this water in composition is dependent upon the, amount of moisture contained in the soil and the humid- ity of the atmosphere because the growth of the plant is retarded or advanced as the amount of moisture in the soil is available. This moisture in turn is controlled more by the soil than the atmospheric temperature. Hence, it is necessary to have moisture in the ground in the right proportion for regulating the heat to retard the process of evaporation as well as to promote the develop- ment of plant food. It is impossible to definitely define what amount of moisture is required for the growth of a plant because a great many conditions enter. A crop may require 300 tons of water for growth to maturity. It may be nec- essary for the soil to furnish 350 tons on account of varying conditions. Some the farmer can control, others he cannot. Water that must be supplied for the growing crops includes that which is constantly evapor- ating from the ground and also that which the leaf and stem of the plant are giving off. The amount of plant food in water is very small; that is, the solution is in a very diluted form. For this reason a plant consumes many times its weight in water to get the necessary food. The principal factor which determines the water requirements of a plant is the humidity of the atmos- phere. In climates where the atmosphere is moist the water requirements for the plants are much less than 16 THE OLIVER PLOW BOOK those in dry climates. The reason for this is the amount of evaporation from the leaves and stems. The more humid the atmosphere the less moisture it takes from the plants, the dryer the atmosphere the more moisture it draws from the plants. If the atmosphere were thoroughly saturated at all times the water require- ments for the plants would be very small because of the light transpiration of water from the soil. Another peculiar fact in connection with the water required is shade. Shade increases the amount of water required for plant growth. It retards the process by which the plant constructs its tissues because the rays of sunlight necessary for this process are dimin- ished. Soil fertility has a great deal to do with the amount of moisture required to grow a crop. A poor soil requires more water than a rich soil for the simple reason that the more fertility there is in the soil the stronger the water holding content. A soil may be fertile in all the elements but one. The lack of this one causes the soil to require more moisture because growth is retarded when a plant fails to get any one of the elements neces- sary. The plant keeps on using and giving off water exactly the same as though all the elements were in the soil. The great problem is to catch and save as much of the rainfall as possible. The ground below the seed bed must act as a reservoir to hold enough water for it to come upward by capillary attraction to the root bed and not escape into the air. Capillary water is that which adheres or clings to the surface of the soil grains and to the roots of plants in films thick enough to allow surface tension to move it INFLUENCE OF WATER 17 from place to place. It is Nature's means of keeping a constant supply where plants can use it. Capillary water is the chief source from which plants derive their supply. So important is capillary water that crops grown on moderately fertile plots where water was supplied as fast as plants could utilize it, produced more than four times as much as the same crop grown in an adjacent field under ordinary conditions. The reason for this is simply that during all the growing period rains do not come at the right times. This naturally prevents the plant food from becoming available every day as the growing plants demand. It is like stuffing a boy one day and expecting him not to get hungry for a week. Feed the boy what he needs each day, and he grows into a strong man. So it is with plants. A BCD The picture (A) of the tube filled with fine soil particles with the clods in the center illustrates very common conditions in plowed ground. The clods in the center prevent capillarity between the upper and lower portion of finely pulverized soil. Consequently, the moisture 18 THE OLIVER PLOW BOOK from below cannot reach the pulverized soil above the clods any faster than the rays of light and heat evaporate from above. This is plainly noticeable in the views showing the water at different heights in the tubes. In illustration B observe that the water has traveled upward in the tube to a level much higher than the water in the pan, showing the force of capillary action. Also observe the firmly compact condition of the earth as far as the water has traveled. m: W*- This is the way plowing is generally done. The large air spaces at the bottom of the first furrow slice and the smaller one in the bottom of the third are often found in fields that have been harrowed and are sup- posed to be ready for planting. These air spaces interfere with the upward trend of capillarity just exactly as is shown in the tubes on page seventeen. The sectional view of plowed ground in the illustration above shows very much the same condition as shown in the tube. INFLUENCE OF WATER 19 In illustration C the water has reached the bottom of the cloddy portion. The uneven edge shows that where the soil particles are compact the water climbs upward, thus illustrating an important characteristic of capil- larity. Too many air spaces in the cloddy ground break up the capillarity so that water will not climb as rapidly or as effectively and abundantly as it does in soil finely compacted. Two hours were required for the water to rise from the bottom of the tube to the cloddy portion. Illustration D is the same tube photographed 22 hours later. Observe that the soil is thoroughly permeated with water up to the cloddy portion, that the moisture in the cloddy part and the pulverized part above the clods is very slight, and that on top no moisture is to be discerned. This shows that moisture does not rise to the surface of the ground any faster than it is evaporated. If this tube contained a plant above the cloddy part it would be plainly evident that the amount of moisture the roots could secure would not be enough to promote the healthy growth of the plant. Therefore, it is very important that this cloddy condition does not exist at the bottom of the seed bed as much on account of moisture as heat and air. Film water displays itself only upon the surface of the soil grain. That is why it is called film water. It forms a film around the grain. Anyone can easily satisfy himself as to the truth of this, by taking a marble and immersing it in a glass of water, then with- drawing it. All the water required to form the film will cling to the marble and the rest will drop off. Suppose that marble is one inch in diameter. It will fill a cube one inch square — that is, six points on the surface of the 20 THE OLIVER PLOW BOOK marble will touch six points of the cube and all the rest of the space between the cube and the surface of the marble is air space. The area of the surface of the marble is found by multiplying the diameter squared by 3.1416, making 3.1416 square inches of film surface for the water. This is the amount of the film surface dis- played. A cube one inch square will hold 1 ,000 marbles one- tenth of an inch in diameter. The square inch of surface of each marble one-tenth of an inch in diameter is one hundredth of what it is on the large marble, or .031416 of an inch. This multiplied by 1 ,000, the number of marbles of this diameter required to fill the cube, makes 31.416 square inches of film surface, in contrast with the 3.1416 displayed in the one marble. Thus, if you take the 1 ,000 marbles in the cube immersing them in water, and withdrawing them as you would the large marble, you would have 31.4 4 - square inches of surface holding water, against 3.1+ square inches on the large marble. This means that the air spaces have been diminished in size and the water holding content of the soil increased, proving that the finer the soil is broken up, the greater water-holding capacity it has, consequently, the break- ing of the soil into fine particles is necessary to improve it for water holding content. For this reason the ground should be well pulverized when plowing. It is further evident, from the marble illustration, that the size of the soil particles has everything to do with the water holding content. As an illustration of the capacities of different soils, for capillary attraction and for holding water, samples of clay, clay loam, loam, sandy loam, and loamy sand were placed in the tubes under the names, small clods being placed on top of the INFLUENCE OF WATER 21 Dipping a marble into a glass of water as shown in this illustration will con- vince anyone that surplus water will not cling to the marble when it is removed. Enough water should be supplied in the soil so that a film of water surrounds the soil grains. The six points of contact leave large air spaces which retard capillary attraction and permit an excessive amount of air and heat to evaporate what little moist- ure may be in cloddy ground. *A r*T T T T T T T T ' <**1 -#1 Jk *k «#I >I -#1 -#X-»j ^1 vl <*± j± j± JW j i >i j>i ./a > a >y 77ie thousand marbles make six thousand points of contact thus showing how much easier it is for moist- ure to travel upward by capillarity, the increased surface for holding film water and diminished air spaces. 11 THE OLIVER PLOW BOOK finely pulverized soil. Clay has the smallest soil particles; clay loam the next larger, loam larger than clay loam; sandy loam larger than loam; and loamy sand larger than sandy loam. This pan was filled with water, giving it an opportunity to rise in the tubes by capillarity. ■ Piig ii Eg €W ^^ **<^ -~» -^~ The five samples of soil in these tubes were ta\en from the same farm. They are shown on pages 39, 41 , 43, 45 and 47. At the top of each tube is a granular mulch. The particles of earth are much coarser than those of the finely compacted earth below. These tubes are eight inches high and two inches in diameter. The earth was packed in each tube to bring about an ideal condition for capillary attraction to act. The soil was also placed in an ideal condition for germination of the seed and the growth of the plant. The surface was not. Do not fail to observe the effect jif this granular mulch in the illustration on page twenty-four. The illustration at the top of page twenty-three shows the water is almost halfway to the top of the finely pulverized earth in the tube of the loamy sand; has a good start in the sandy loam; is just beginning in the loam; is hardly perceptible in the clay loam, and not at all in the clay. Thus, we observe that up to this period capillary attraction is faster in the sandy soils than the clay, and that the loam is about midway between. The second illustration on page twenty-three shows the water in the tube filled with clay has just started INFLUENCE OF WATER 23 iOA.\n SAND while that in the loamy sand tube has almost reached the top. The clay loam, loam, and sandy loam are still drawing water in about the same proportion as shown in the previous illustration. The illustration on page twenty-four shows the water in the tube filled with loamy sand has reached the cloddy portion, while that in the clay tube has gone about one-fifth of the way to the top of the tube. The water in the other three is still climbing in the same proportion, thus showing conclusively that the finer the soil particles are, the slower the water rises. HI 24 THE OLIVER PLOW BOOK Another feature that must be taken into serious con- sideration is that soils, in which water rises rapidly, dry out equally fast, thus the sandy soils dry out much quicker than the clay soils, all of which goes to show that the finer the soil particles are, the stronger the attrac- tion to hold the water. Compare the water in the loamy sand and clay tubes illustrated on page twenty-three with those illustrated above. The granular mulch on top the tube of loamy sand stopped the upward trend of moisture as the distance the water in the clay tube has travelled upward shows. The moisture in the loamy sand tube has climbed from a point just below the Wire to the granular mulch while the water in the clay tube travelled twice as far as it had, thus showing that the granular mulch stopped the upward trend of moisture. This illustration serves to show the import- ance of peeping the soil particles on the surface in an entirely different arrangement from those below in order that capillary attraction may be permitted to act up to this point and then stopped, thus keeping the moisture in the ground. Observe further the soil at the top of the tube filled with loamy sand; that the water has not penetrated the clods to any appreciable extent. Bearing in mind the illustration of the tube with the clods in the center, it will be observed that a granular surface on top is better to prevent moisture from escaping into the air than the finely pulverized soil. The reason for this is simply that capillarity has been broken up between the com- INFLUENCE OF WATER 25 pact sub-surface and the granulated top. For this reason it is better to have the lower portion of the soil compact and the layer on the surface coarse and granular than to have it all finely pulverized. When a farmer desires to plant a field infested with cutworms, grubworms, wireworms, or some other pest which can be eradicated by plowing, he wants to know whether it is best to plow for the express purpose of kill- ing the insects, for the conservation of moisture, or at a time of the year when plowing can be easier done. He must decide which is the most important and plow ac- cordingly. The number of times that one would run into difficulty with moisture when plowing to kill insect pests would be very few because the ideal time to plow to kill insect pests is during their larva state, which for the most part is in the fall of the year. If one plans on plowing sod with the expectation of growing a crop it is better to fall plow for the moisture conservation process and also for the killing of insect pests. The small profit that may be made in pasturing such fields is much less than the total accruing from plowing in the fall previous to planting. This has been dem- onstrated sufficiently to be stated as a fundamental fact. If one studies carefully the conditions mentioned it is evident that the damage done during dry periods can be minimized by having the soil kept in the proper physical condition by the right kind of tillage to save moisture for use at this time. From the foregoing it is obvious that soil moisture very often determines whether a yield will be large or small. The same needs for moisture are present, north, east, south and west, and the same laws for con- 26 THE OLIVER PLOW BOOK serving must be applied. The degree to which this conservation must be practiced is determined solely by the amount of moisture contained in the soil. In the more humid districts it may be only necessary to adopt a system for conserving the rains of summer and fall; whereas, in the dryer territories it may be necessary to practice a system of summer fallowing for an entire year before enough moisture can be saved to insure a crop. The big thing to remember is that moisture must be present when the plants need it. Those farms underlaid with clay soils are easier to till for conserving moisture for future use than those which have an endless depth of sand or gravel. If the sub-soil is of such a nature that it will not hold moisture within the distance which capillary attraction operates, the problems are extremely difficult and almost beyond control unless the soil is kept chock full of humus at a depth deep enough to prevent surface heat from evapor- ating the moisture. CHAPTER III Importance of Air in the Soil WATER, heat and oxygen are necessary for the germination of seeds. Oxygen must come from the air, hence it is necessary, in the preparation of the seed bed, to leave the ground in condition for the cir- culation of air. In view of the fact that seeds must germinate before the plants can grow, the nearer the oxygen and moisture are in the right proportion in the ground, the more rapid will be the germination and growth of the plant. In the development of plant food for growing plants the elements that go to make nitrates are largely con- fined to the first few feet of surface soil. If the soil is loose enough to allow access of air, nitrification is more rapid, hence plant growth is more rapid. It obviously follows then that plowing and cultivating are necessary for the development of plant food. Air is also necessary to keep the ground in condition for the retention of plant food after it has reached the nitrate form. The roots of plants need oxygen in the process of growing. Energy is required. The roots penetrating through the ground absorb the oxygen and thus acquire the needed energy for the work of pushing the soil particles to one side. Nitrogen, in the form of nitric acid, is the most im- portant of all plant food elements. Oxygen gives life or activity to prevent destruction of nitrates after they have once been made. Wet soils, rich in organic 28 THE OLIVER PLOW BOOK matter, often give off more free nitrogen than is used in forming the nitrates in them. Thus they become depleted on account of too much water and not enough oxygen. Too much oxygen in the soil burns up the fertility and has a tendency to form clods. Seeds will not germinate in ground from which oxygen has been completely excluded; neither will growth take place. Water, completely filling pore spaces, excludes oxygen. This is another way of saying that plants drown. The human being drowns because oxygen is excluded from the lungs; so do plants. Compact earth prevents This illustration shows a soil that had been covered with water for a long time. The excessive air spaces caused by these cracks are due to the shrinking of the soil particles after the swelling caused by the water. It is easy to see that the cracks penetrate deeply thus causing the air and heat of the sun to evaporate the moisture from a great depth. circulation of air and creates a condition fatal to growth, even if the ground contains sufficient moisture. Some authorities claim poisonous gases are formed by this condition. While the evil effects of excluding air from the soil are many, it is equally true that too much air is harmful. Air is just as essential in the forming of nitrates as IMPORTANCE OF AIR IN SOIL 29 moisture. Consequently, if all the air were removed from the ground there would be no forming of nitrates, and plant food could not be produced. Too much air makes cracks and fissures in the soil, drawing out moisture, oftentimes to such a depth as not only to stunt the crop, but kill it. Too much air in the soil in the spring can easily cause the loss of enough moisture to grow a crop. It is a well known fact that the atmospheric pressure on the earth's surface is 14.7 pounds per square inch at sea level. The amount of nitrogen in these 14.7 pounds of pressure is 77%. It is perfectly logical, if the ground is broken up and thoroughly pulverized when plowing, that this pressure of 14.7 pounds per square inch will force the air into the soil taking with it 77% of free nitrogen. It is the air circulating around every particle of soil in conjunction with capillary moisture that liberates plant food for the growing plants. This field is similar to that shown on page twenty-eight but in a much less aggravated form. However, if left to itself for any length of time it is easily possible to see how the cracks would widen and deepen. 30 THE OLIVER PLOW BOOK Scientists tell us that wheat, oats, barley, rye, etc., take up the nitrogen, which they use from the roots, and then only in nitrates in dissolved form. Hence, nitrogen must be available in the ground. The more nitrates there are in the ground per acre the greater chance the farmer has of growing increased crops. He may have his phosphorous, potassium, cal- cium and water, but unless he has the nitrogen which he can get from the free air, he can never grow the proper kind of crop. Since the need for air in the soil is highly important it behooves the plowman to be very careful to see that the ground is thoroughly pulverized and that all large air spaces are eliminated and the after preparation of the seed bed made so as to keep the air and moisture mixed in the ground in as nearly the perfect proportion as possible. Enough has been said to show that the perfect condition in all soils is when the soil has natural air spaces between the soil particles. This is one reason why Nature makes soil particles with irregular surfaces. The best way for aerating the ground is to thoroughly pulverize when plowing. To be sure of this requires a study of the shapes and sizes of plow bottoms, because different soils require different shapes, sizes and curva- tures of bottoms to bring about the desired result. Also the time of the year that the plowing is done with relation to the time elapsing between the plowing and planting has a great deal to do with the success of this practice. In the chapter on the temperature of the soil atten- tion is called to the difference in the temperature required for the most propitious development of plant food and the planting of wheat to resist the winter's freezing. IMPORTANCE OF AIR IN SOIL 31 - i 1 Observe how deeply fissures will penetrate the ground when conditions are ripe. This condition can only be prevented by a mulch of earth on the surface to \eep moisture travelling upward from the ground water level to the mulch, and the rays of heat and light from penetrating. Summing up the importance of air in the soil, temper- ature and plant food development, and the killing of insect pests we find that early summer plowing, with complete burying of stubble and trash on the bottom of the furrow, is the best method for killing the Hessian fly, and aerating the soil at a time when nitrates develop best. At this time there is the least amount of rainfall to wash away plant food and the soil is in the best possible condition for the percolating and saving of what rain does fall so that later in the fall when the time comes for planting wheat it is at a cooler temper- ature with plant food enough developed for giving the wheat a remarkably good start, thus lessening its chances of winter killing. CHAPTER IV Soil Temperature FOR centuries farmers have observed that some soils are seemingly better adapted than others to grow certain kinds of crops. These observations naturally have led to what is called "wheat soil," "barley soil," "rye soil," etc. While these observations on the face of them would lead one to think that some soils are more adapted than others for crop growing, there is a great deal of doubt as to their real merit because in the light of present-day experiments crops have been grown in pure sand which had been supplied with the plant food elements and the amount of moisture necessary to grow plants. Climatic conditions have much to do with crop grow- ing, consequently, when one begins to study what crops that soil is to produce, he must take into consideration the climatic conditions as well as the soil. Naturally then, if a farmer can supply a soil with conditions equivalent to climate, he can, to the extent of that ability, grow plants in any soil. The wheat and oat plants offer an interesting illus- tration of this fact. Assuming that the proper fertility is in the soil, whether it is sand or clay, climatic con- ditions, that is, temperature and water, must determine the growth. Up to the time of ear shooting wheat needs wet, but not too warm weather; at flowering SOIL TEMPERATURE 33 time, dry, warm weather; during the ripening period, medium moist weather, and dry weather for harvest. The oat does best in moist and relatively cool weather. It is not to be supposed that it is possible for a man to control the temperature of the soil to the degree that he can bring about climatic conditions for growing a crop, but by the proper conservation of moisture and cultivation of the soil it can be made warm in the spring Ground in this condition becomes too hot in the summer for the suc- cessful development of nitrates for growing corn. This soil, a silt loam, requires very careful handling to prevent its powdering. when it otherwise would be cool, and cool in the summer when it otherwise would be hot. To this extent the temperature of the ground can be controlled. This aids very materially in the growing of crops. The means for bringing this about center around the amount of moisture in the ground and the rapidity with which it 34 THE OLIVER PLOW BOOK is permitted to evaporate. The evaporation of moist- ure is determined by the kind of soil, its compactness, the amount of surface exposed to the rays of light, and the wind. The greatest difference in temperature between the different types of soil takes place in the early spring thawing and the period immediately follow- ing. This is of utmost importance to farmers especially at planting time because a small amount of difference in the temperature of the ground means speeding up or retarding the rate of germination of the seed and the growth of the plants. Other things being equal, it logically follows that the sandy types of soil can be planted earlier in the year than the clay types. When a soil is cultivated a larger area of its surface is exposed, thus the amount of evaporation is very much greater. The result of greater evaporation is that the temperature of the cultivated soil rises much higher and faster than that of the uncultivated, and permits earlier planting. This is one of the strongest arguments for fall plowing and leaving the ground rough. In the spring of the year the additional exposed surface dries out much more rapidly and thus permits earlier seeding. The most interesting part of this process is that as soon as a dry mulch of this earth is formed on the plowed soil the loss of water by evaporation is reduced very much, while the loss on the unplowed soil is still greater. In the summer this reduces the temperature of the mulched ground, while that of the unplowed ground is considerably raised. A further observation is that the heat which is not utilized in the evaporation of water is being rapidly conducted downward in the unplowed ground, thus causing it to dry out at great depth. On the cultivated SOIL TEMPERATURE 35 or mulched land only a small part of the heat is con- ducted downward. The other is radiated back to the atmosphere by the dry ground on top. This is because the mulch breaks up capillary attraction with the moist soil below, acting somewhat as a blanket to hold the moisture down and keep the heat out. When this mulch becomes completely dry, as it often does, during the hot summer, it radiates back large amounts of excessive heat to the atmosphere, thus, we find the effect of this mulch upon the soil as follows: It prevents the soil from reaching a high temperature during the day and a low temperature during the night; it greatly warms the soil in the spring; it tends to con- serve moisture in the lower strata and consequently reduces the rate of cooling in the summer. The im- portance of this is very manifest when one considers the temperature necessary for the development of nitric acid. Soluble nitrates do not form at a temperature below 41° Fahrenheit. The most favorable temperature is between 60° and 85° Fahrenheit. They form very slowly at 115° and at 130° will not form. It has been determined that wheat germinating at a temperature of 40° Fahrenheit is more resistant to cold than wheat which germinates at 64°. Obviously, the temperature for the greatest formation of nitrates, which are neces- sary for the development of plant food, is too high for the successful growing of wheat to withstand the winter's freezing. This makes it necessary, if the most favorable condition for wheat is to be brought about, to plow the ground and keep the seed bed at a temperature of from 60° to 85° Fahrenheit in order that plant food may be developed for the growing of plants which must be grown at a cooler temperature. CHAPTER V Why Soils Must Be Handled Differently THE soil is the farmer's working capital. It is neces- sary that this capital be used in the wisest possible manner to earn the profit which justly belongs to him. Carelessly handling the soil results in a loss just exactly in the same manner as the mishandling of working capital results in loss to a manufacturer. The broad business principle underlying manufacturing and farm- ing is identical but the tools and working capital of the two are widely separate and hence must be handled in a manner peculiar to each before either can achieve success. Soil is a combination of disintegrated rocks, dead vege- tation and many living forms, such as bacteria and fungi. Broadly speaking, soil may be regarded as matter in which a planted seed can grow to maturity. The difference between soil and earth or ground, from a practical standpoint is so slight that the terms are almost synonymous. When comparing the mode of life of the plant with that of a human being, the soil around the plant may be regarded as the dining room in which the plant eats, the kitchen in which its food is prepared, the storehouse where the food elements are kept in reserve, a reservoir for the water and a ventilating system. When one reflects upon the numerous results this working capital is supposed to produce, the more concerned one becomes as to how it should be treated. 38 THE OLIVER PLOW BOOK It is plainly evident that all these conditions are necessary to bring about plant growth. When we understand that plant growth, in the form of either legitimate crops or weeds, consumes plant food, or fertility and the water which is contained in the soil, we see why it is necessary to replenish the fertility and change the condition in this ground before new develop- ment of plant food will take place. Plowing is the only means known to human endeavor that will successfully start this process. It is highly important then, that one should understand the peculiarity of the soil he desires to plow before he can do this efficiently. There is scarcely a farm, regardless of how small it may be, that is made up of less than two distinct soil compositions. The fact that most farms are made up of several soils, some of them radically different, means the necessity for a thorough understanding of the types because they must be handled in an entirely different manner to bring about good results. There are many soil combinations but the most common are clay, loam, clay loam, sandy loam, loamy sand, sand and muck. We will go into some detail in the clay, loam and sandy soils because they are by far the most common and will serve as illustrations of the fact that each soil must be tilled according to its kind. Indeed, there are many types of soils that are never mentioned in books which have bountifully repaid the tillage of farmers who studied their characteristics, and by long, bitter experience learned how to handle them for crop growing. Clay is the hardest soil to till on account of the peculiar effect water and air have upon it. It holds DIFFERENT HANDLING OF SOILS 39 This sample of clay and the soils illustrated on pages 41, 43, 45 and 47 were taken from the same farm, comprising 240 acres. These entirely different soils coming from one farm offer the strongest evidence that every farmer should thoroughly understand soil composi- tion. A careful examination will reveal the similarity of the speci- mens to the land being plowed. The same peculiarities of the clay soil in this plowed ground obtain in the specimen above. Finely pulverized earth is not to be seen. moisture longer than any other kind of soil with the possible exception of peat; bakes hardest; forms clods easiest and cracks into deeper fissures, per- 40 THE OLIVER PLOW BOOK mitting great quantities of moisture to escape. Clay never works up into a loose, mellow seed bed, but rather one of clods or fine dust which blows easily. Cultivated when wet, clay forms into clods of different sizes, from that of a walnut to as large as a person's head, depending upon the kind and amount of cultivation. The grain is fine and has a peculiarity not discernible in any other type of soil. Moist clay is soft and sticky. It can be kneaded and formed into various shapes and bodies. Small boys, unable to buy marbles, use clay very successfully for making them. A small piece of clay can be easily smoothed and polished by the fingernail. While polish- ing a greasy or soapy feeling will be noted. Moist clay, when rubbed between the thumb and finger, has a slip- pery feeling. Persons walking on a sloping bank of wet clay are apt to have their feet slide out from under them very suddenly. Clay in a powdered condition when moistened, has a peculiar odor unlike anything else. Clay in color may be red, yellow, blue, white, black or chocolate. For the most part clay soils when plowed too dry, form large clods which are decidedly hard to break into pulverized condition. If such soil lacks humus in sufficient quantities to keep it friable, it nearly always forms a powdered surface. Among these peculiarities of clay the fact that it holds moisture longest, bakes hardest, and forms clods easiest should be a warning that the greatest of care must be exercised in plowing dry clay soils, if there is a possibility of rainy weather com- ing between the time of plowing and planting, because the dry soil in this powdered condition will run into a sticky, plastic mass which will later dry hard and crack DIFFERENT HANDLING OF SOILS 41 In this specimen of clay loam soil the peculiarities of clay predominate but the smaller clods to the right show that this soil can be pulverized more effectively than the clay soil. The finer pulverized earth distinguishes this clay loam from the clay soil, but many of the distinguishing characteristics of clay can be readily seen. so that it cannot be broken up successfully by any kind of cultivation. This peculiarity of clay has led many farmers to ridicule so called scientific methods of farm- 42 THE OLIVER PLOW BOOK ing because they were told that it was impossible to disk or harrow too much. A winter's freezing is the only successful treatment for rectifying' the evil done by plowing a dry, clay soil lacking in humus and within the limit of abundant rainfall and planting the crop. Farmers who live in climates where there is no oppor- tunity for freezing can ponder with a great deal of profit upon this problem. It is common knowledge that a soil plowed wet will dry out more rapidly than unplowed soil. Plowing wet clay has the same effect that plowing a wet sand soil has as far as the drying out is concerned but with entirely different results. Clay, being of a plastic nature and sticking close together, is puddled by wet plowing. It is turned over in a closely compacted manner so that the top drys out first leaving a slower drying process for the bottom of the furrow. This naturally means that avenues of escape must be formed for the moisture below. These avenues will appear at the place of least resistance in the soil. These places are caused by the action of the mouldboard in turning over the soil. The result is a cloddy formation at the bottom of the seed bed which locks up the soil fertility in the clods, interferes with the upward trend of capillarity and makes absolutely im- possible a final preparation of the seed bed. The plow mouldboard working in wet clay performs exactly the same operation as a brick making machine does in molding the clay into bricks, hence in the handling of clay soils the plowing must be done at a season of the year when clods will not be formed. When one considers that clay soil holds moisture longer than any other type of soil it is obvious that clay DIFFERENT HANDLING OF SOILS 43 This specimen of loamy soil does not reveal either of the character- istics of the clay or the sand but does show a combination of the two in such form as to make this soil readily tillable. Observe in this plowing the absence of large clods and the same granular appearance that is plainly noticeable in the illustration above. land tilled in such a way as to conserve moisture will stand drouth much better than coarser grained soils. Fall plowing of clay soils in climates where the ground freezes deep enough to separate the soil particles is becoming more generally practiced. The reason is that 44 THE OLIVER PLOW BOOK whether or not the ground is in ideal condition for plow- ing in the fall it can be turned over covering up the vegetation so that it will rot during the winter, and in the spring when the ground thaws the soil will be in condition for the successful making of a seed bed pro- viding it is not harrowed when wet. Care must be exercised however, in fall plowing of clay soils, to leave the ground rough because if it is left in a smooth con- dition the surface soil will run together by the action of the water in the spring, bake, and form a crust that will be difficult to handle. The principle underlying all this is simply the importance of permitting the surface moisture to escape and holding that which is below in the ground. If this idea is thoroughly understood the handling of clay soils need not necessarily be difficult, but one must have enough power on his farm and the right kind of plow to do this work when moisture con- ditions are right. The unfortunate part of putting off plowing clay soils until spring is that the farmer is taking one of three chances. The soil may be ideal for plowing, it may be too dry or it may be too wet. When the soil is ideal everything is propitious, no damage done. When the ground is too dry it is impossible to make an ideal seed bed on account of one of the two extremes — the ground plows up into either hard clods or fine dust. When the ground is too wet the condition that has been mentioned previously in reference to puddling of clay soils obtains. It is doubtful whether one would take such chances if he thoroughly understood the damage he is doing by postponing the plowing. Of course, the argument that farmers do not have time to fall plow every year carries a great deal of weight because it is absolutely true. But why is it not possible to plan a crop routine in which this principle is taken into con- DIFFERENT HANDLING OF SOILS 45 In this specimen of sandy loam traces of the clay are noticeable but the sand predominates. Obviously the selection of a plow for turning this type of soil must be different from that used in plowing clay soils. Observe the characteristics of the sandy loam soil in this picture, and also the different manner in which the furrows are laid from that shown in the plowing of clay on page thirty-nine. sideration? A great many farmers are now following such plans and the results show the wisdom of this practice. Loamy soils are made up of sand and clay in such composition that the identity of each is lost. When pressed 46 THE OLIVER PLOW BOOK between the thumb and finger a granular, raw feeling is distinctly noticeable. It has neither the rough, gritty feeling of the sand nor the smooth, slippery feeling of the clay. A ball of dry loam is porous while a ball of dry clay is compact. Loam crumbles readily, making it easy to plow and cultivate. It dries out faster than clay, and slower than sandy soils. It does not form hard, unbreakable clods like clay, nor does it crumble so easily as sand. It forms into a mellow, compact seed bed, and gives the farmer more return for poor cultiva- tion than any other soil. These characteristics of loam undoubtedly give rise to the statement that anyone can throw seed into the ground and it will grow, meaning, of course, that anyone can farm. The expression, clay loam, means that the clay pre- dominates in the composition, and sandy loam means that the sand predominates in the composition, there- fore, the handling of a loamy soil must be more inclined towards the soil which predominates. That is, a clay loam soil should be handled more like a clay soil and a sandy loam should be treated more like sandy soil. Clay loam is much easier to plow and cultivate than clay because the sand in the loam breaks up the com- pact relationship between the clay particles. It has much the same texture as clay soil. It can be worked to better advantage than clay soil when wet, although not successfully. It forms a more compact and mellow seed bed. The cloddy formation is less predominant than in clay. It has the clay characteristics of cracking and drying out and must be handled in such a way as to prevent this. Sandy loam can be told very readily by its grain. Sometimes the particles are large enough to be easily DIFFERENT HANDLING OF SOILS 47 This specimen of sandy soil shows how quickly it dries out. The blurred portion to the right was caused by the soil drying and falling at the moment the photographer was exposing the negative. In this illustration of plowing sandy soil the furrows are regular in shape from one end to the other. The finely pulverized ground is just as noticeable in the plowed field as in the specimen shown above. 48 THE OLIVER PLOW BOOK seen by the naked eye. They can always be distin- guished by the use of a magnifying glass. A sandy, gritty feeling is noticeable when rubbing the soil between the thumb and finger. This is a never-failing way of recognizing a sandy soil of any character. The sandy loam, as the name signifies, is a mixture of sand and clay, with the sand in larger quantity than the clay. This makes it a less porous soil than the loamy sand, but more porous than clay. It works up easily, does not form hard, unbreakable clods, and is particularly well adapted to the growth of tuber crops. It does not require so much effort to plow or work up into a seed bed as clay loam, but requires more effort than the loamy sand. Loamy sand is a combination of sand and loam in different degrees than sandy loam. Sandy loam con- tains more loam than sand, and loamy sand more sand than loam. The easiest and best way to distinguish be- tween these two types of soil is to make them into balls. The sandy loam will hold its shape, while the loamy sand will not. Loamy sand dries out the quickest of any type of soil. It is the easiest to plow, it never forms clods, is coarse grained, and is easily distinguished by the gritty feeling experienced by rubbing it between the thumb and forefinger. It is a soil that has to be handled with the greatest of care or it will produce nothing. It readily blows on account of the rapidity with which it dries out. The grains of sand are much coarser than particles of clay. Obviously, there will be larger air spaces. These air spaces permit moisture to percolate downward rapid- ly. Sand, in a loose condition is thus easily packed by a heavy rain. The water percolating downward naturally DIFFERENT HANDLING OF SOILS 49 carries with it the grains of sand until they strike other grains and cannot be carried farther. Thus, the process continues until the final arrangement of all the soil grains is such that there is no further opportunity for the force of gravity to operate. This principle must be carried constantly in mind when farming sandy soils because the water compacting the soil in this manner on its downward trend makes the finest capillary connec- tion possible between the top of the ground and the lower surface. Thus, when the weather warms to such an extent that water vaporizes on the surface, moisture is drawn from below by capillary attraction with great rapidity. The only way that this can be stopped is by changing the relationship of the soil particles on the surface. This can be brought about by the use of any implement that will stir the soil. What- ever implement is used, the relationship of the soil particles must be entirely changed so that the moisture from below cannot escape into the air by capillary at- traction. With this understanding it naturally follows that sandy soils require more frequent liming, fertilizing and a greater amount of humus than the clay soils, also more frequent cultivating on the surface if one expects to get the most out of them. A question often arises as to the advisability of plowing sandy soils in the fall for spring planting. These water peculiarities of sandy soils make a great difference between the time of plowing and the planting season. In the chapter on the temperature of the soil, reasons are given as to why sandy soil be- comes warmer earlier in the spring than clay soil. This earlier warming of sandy soil and the quickness with which the soil compacts offer good reasons for per- 50 THE OLIVER PLOW BOOK mitting a much shorter time between the plowing of the ground and the planting of the crop. The practice of growing a green cover crop of some sort and plowing it under in the spring of the year instead of in the fall is proving to be a very beneficial and profitable process for sandy land, particularly if those cover crops are nitrogen bearing plants, such as clover, etc., simply because being plowed under in sandy soil, they form a sort of reservoir for holding moisture as well as yielding nitrates. The fact that sand does not form clods or large air spaces makes a practice of this kind profitable on sandy soils in the spring whereas it would prove detrimental on clay soils on account of the tendency of these soils to form clods and air spaces on the bottom of the seed bed. CHAPTER VI Depth of Plowing DEPTH of plowing has been argued pro and con for many years. A depth of six inches is regarded as deep plowing by some and shallow by others. In this dis- cussion two to four inches is regarded as shallow, four to eight inches as medium and eight to sixteen inches as deep plowing. The question that interests every farmer and one that he must decide for himself is whether he shall practice shallow or deep plowing on his farm, and not what his neighbor regards as deep or shallow plowing. One farmer makes great success of deep plowing, another plows just as deep and meets with dismal crop failure. One farmer plows deep in the fall and grows a good crop the next year, another plows just as deep in the fall and has a dismal failure the next year. The same results are happening in deep spring plowing. These being facts beyond dispute, something besides the mere act of plowing must be taken into consideration before a conclusion can be reached. Advocates of deep fall plowing center their arguments around the theory that deep plowing in the fall turns the raw earth to the surface giving it the advantage of the winter's freezing and atmospheric influences to bring into play the fertility which is supposed to have lain dormant or in unavailable form. The experience of those who have deep fall plowed with disastrous results the next year would tend to disprove this theory. The fact that many men have deep plowed in the spring with successful results would tend furthermore to prove that fertility is made available by deep plowing in the spring. 52 THE OLIVER PLOW BOOK These observations tend to the belief that those who plow deep in the fall with bad results the next year, must not have had fertility on the surface of the plowed field or the winter's freezing destroyed it, and further that the deep plowed field in the spring contains fertility. If one regards these deductions as logical, the question as to whether one should plow deep or shallow in the fall or spring must be solely determined by the condition of the land. The farmer must be absolutely certain that he has the plant food elements in the soil either in avail- able or unavailable form, and also whether freezing influences are necessary for the liberation of that food. How can this be determined? It is doubtful whether samples taken from the surface of a plowed field and examined by a soil chemist would be of any practical value to the farmer for the simple reason that the soil chemist would be unable to tell as to the availability of these elements in the soil. The most the chemist can do is to determine the amount and kinds of elements that are in the sample submitted. These deductions are apt to be entirely wrong as far as the quantity over the whole field is concerned. It is a question whether any man by following this method can ever be sure as to what the soil needs on account of the uncertainty of the amount of plant food elements of all kinds existing in different portions of the field. A much better way for a farmer who is not positive as to what he is going to accomplish by deep plowing is to do a little experimenting of his own. It can be done very successfully providing the experimenter has learned how to handle the different soils as discussed in Chapter V. DEPTH OF PLOWING 53 Take five potfuls of soil from the field and test for the elements required to grow the crop. In each of these pots plant a few seeds of the crop desired to be grown. To the first pot add nothing, to the second, a quarter teaspoonful of sulphate of potash, or if that is not obtainable use a teaspoonful of wood ashes. To the third pot put a combination of the phosphate and potash, to the fourth a quarter teaspoonful of sodium nitrate or ammonium sulphate, and to the fifth a com- bination of acid phosphate, sulphate of potash and Whether the ground is plowed deep or shallow the condition of the earth shown in this cross section of a plowed field must obtain before the seed bed can be made a success. Deep plowing often shows a good surface and hides a bad furrow bottom. sodium nitrate. This sort of test is not, strictly speak- ing, scientifically accurate, but it is close enough to show anyone which of the three principal plant food elements, phosphorus, potash and nitrogen, are lacking in the soil. If the plant in the first pot refuses to grow, it is plainly evident that the soil is lacking in plant food elements. The growth of the plants in each of the pots will signify in what the soil is lacking and what will be necessary to 54 THE OLIVER PLOW BOOK add to that soil before it will produce. It is further logical to assume that if the best growth takes place in those pots that contain fertilizer or the plant food elements which the farmer cannot hope to add to the soil, it is unwise to plow the ground to that depth whether he does it in the fall or spring. We often deceive our- selves into thinking that soil plowed eight, nine, or ten inches deep turns up soil fertility when it does not. As far as the writer has been able to learn, there have never been experiments tried to prove that winter's freezing unlocks soil fertility any more than that the winter's freezing of certain soil particles such as clay, has a tendency to flocculate the soil, or break it into small particles, so that the fertility contained in the soil is made more available. Obviously then, one must suppose that before deep fall or spring plowing is indulged in it is necessary to know whether the deep soil contains available fertility. The other important question to decide is whether or not the plowing can be done so as to leave the ground in the proper tilth and condition for plant growth. This can only be determined by having a knowledge of the soil and how to handle it to bring about conditions of tilth. The one great advantage of deep fall plowing over deep spring plowing is that the fall plowing receives the aid of time, moisture and freezing to break up cloddy formations that may have resulted from the plowing and to compact the soil into a suitable condition for capillar- ity to take place. In deep spring plowing, the ground is often turned over in cloddy formations which are detrimental to the compacting of the soil at the bottom of the furrow on account of the depth at which it must DEPTH OF PLOWING 55 be worked. The result is a seed bed with a poor cap- illary connection with the sub-surface. This fact, and also the fact that barren soils are often turned over make deep plowing in the spring questionable in a great many localities, but where the soil can be turned over in a friable condition and contains abundant plant food, there is little to worry about deep plowing in the spring providing the seed bed is compacted as it should be. This depth of plowing attempted with a bottom designed for medium depth plowing reveals a badly turned furrow slice, poorly cleaned furrow bottom. The illustration on the next page shows a side view of this plowing. 56 THE OLIVER PLOW BOOK Deep plowing cannot be done successfully with a plow having a capacity of not more than seven or eight inches in depth, because it cannot possibly break up or pulverize a deep furrow. This fact should be taken into serious consideration by anyone who attempts to do deep plow- ing if he expects to plant a crop soon after the plowing is done. Its curvature and shape will permit the passage of thick slices over the mouldboard. But when the plow is penetrating a depth beyond its capacity it pulverizes poorly to that depth and the rest of the slice is broken into clods which are usually thrown on the bottom of the furrow. For this reason one who expects to turn a depth of eight inches or more should secure a plow with a bottom designed for this type of plowing. Part of the furrow is turned on edge and is almost ready to fall bac^. Attempting to use a plow having a capacity of eight inches in those soils that stick together has a tendency to set the furrow slice on edge and oftentimes the furrow slice rolls back with the sod on top. Thus, the furrow itself effectively offsets any influence the plow bottom may exercise towards pulverization. This fact also accounts for a great deal of deep plowing failure because DEPTH OF PLOWING 57 ■^ Plowing eleven inches deep with a bottom made especially for deep plowing. Observe the clean furrow, smooth furrow bottom and wall, and the furrow slice turned over properly. This plowing is in great contrast to that illustrated on page fifty-five. On account of the depth at which this plow is working the greatest of care should be exercised to see that the bottom of the furrow is properly made because none of the after preparation implements such as the disk, harrow, peg harrow, or roller pulverizer can exert much influence on the bottom of the furrow. the seed bed is left in such a manner that moisture cannot come up from below by capillary attraction and that which is on the surface either washes away or sinks into the subsoil where it cannot rise again. 58 THE OLIVER PLOW BOOK We must remember whether we are plowing shallow, medium, or deep that the ground must always be left in condition at the bottom of the furrow for capillarity to take place with the subsoil. We cannot judge this by looking at the surface. It is necessary to dig into the ground the depth of the plowing and observe the condition. When we do this we will often see things that surprise us, and the explanation for many a deep plowing failure can be satisfactorily found. The great advantage of deep plowing is that it offers deeper root beds for the crops. The mellower the ground is the easier the roots grow and penetrate. fe*3fls*i;» ■-'■ -■%< # ■''^jt : ^M&>~ LJ^^ * .S/•>■-■ ^ fc v -r ■ > 3a Ii AS 3 S ■5-5 J 112 THE OLIVER PLOW BOOK a slanting cut. This also has a tendency to make the plow pull lighter in draft than a plow with a straight landside. These few illustrations serve to show that it is highly important to select a plow bottom for handling the soil the way it should be, and also that when any doubt exists to consult a plow expert before a radical change is made in bottoms. Generally speaking, the type of plow bottom that does the best work pulls the hardest because the old law that so much energy is required to produce a given amount of work is applicable to plow bottoms. Less power is required to break a clod into three parts than into a million. The breaking of earth into finer particles is highly important if the proper seed bed is to be prepared. Tests have been made which show that mouldboards curved to do the pulverizing require more energy or power than the bottoms which break the soil into clods. The four illustrations showing sectional views of plowing are the results of a test made purposely to deter- mine whether the plow bottom that did the best pul- verizing pulled heavier than the one that did the inferior grade of work. This test was made in a field of very heavy clay and sand not in a loamy combination. It had not rained for several weeks. All the tests were made in the morning of the same day in order that there should be as little change as possible in the moisture content of the ground. The only difference in the plow bottoms was in the shape of the mouldboards. Thus, the condition for all the plows was the same, the only dif- ferent contributing factor being the mouldboard. PLOW BOTTOMS 13 ■- * '"J |iSl|||Si jp ,. : A •-/•--.-•• 1 6* •f<* f . HHHB Figure 1 Note the thorough pulverization of the soil, the foot prints which show the dry condition, and the absence of air spaces. Figure 1 shows a job of plowing almost ideal. One would not expect it in soil as dry and hard as this but the plow pulled 14% heavier than the plow bottom which did the poorest work, or that shown in Figure 4. Figure 2 This plowing is not so well pulverized as that shown in Figure /, but it could be regarded as a fairly good job of plowing dry soils. The plowing shown in Figure 2 is not so good as that in Figure 1 . The ground is not as finely pulverized. The plow bottom pulled 4% lighter. 114 THE OLIVER PLOW BOOK Figure 3 The clods are larger than those shown in either of the two previous illustrations. The air spaces at the bottom of the furrow slice are more pronounced, and the furrow slice shows cloddy formations rather than pulverization. The work in Figure 3 shows that the earth was turned up into clods. There is little pulverization. The bottom used in doing this work pulled 13% lighter than the one that did the work shown in Figure 1 . - Figure 4 Clods are larger than in Figure 3. The furrow slices are unevenly formed. They are merely larger clods intermingling with smaller ones and the finer soil particles. There is no indication of pulverization which is necessary for the proper aeration of the soil. The plowing done in Figure 4 shows the ground broken into large clods, little or no pulverization and very im- perfect furrow slices. This job required less power by 14% than the one shown in Figure 1. PLOW BOTTOMS 115 When one considers that the pulverization of the soil is vitally necessary in by far the greatest number of cases he will pay less attention to the draft of the bottom and more to its adaptability. Sufficient power should be used to do the work well. An experiment was made with the bottoms shown in illustrations F, G, K and M to determine just what effect different shaped mouldboards have upon the soil. This experiment was made in a field of clay soil thoroughly saturated with water. It was necessary to perform such an experiment with a soil that would hold together sufficiently to make observations. Wet clay is the best kind of soil for this purpose. These four types of plow bottoms are for use, as the descriptions read, in widely varying soils. The illus- trations of the work done by these bottoms in the soils for which they are adapted, when compared with these illustrations, must forcibly call attention to the impor- tance of selecting a plow bottom adapted to the soil. These experiments were conducted in the morning of the same day in order that the moisture content should be as nearly uniform as possible. These illustrations also show the relative work done by the share, mouldboard and landside in such a way as to call attention to the difficulty encountered in trying to establish a fixed center of draft that will serve as a guide for all shaped plow bottoms and soils. While this question would be more properly discussed in the chapters on plow hitches, these illustrations are so pertinent that the reader's indulgence for this deviation from good sequence is asked. 116 THE OLIVER PLOW BOOK The right-hand side of the furrow slice is laid on the furrow bottom in such a way that the forward travel of the mouldboard will give it a pinching, crushing motion to separate the soil particles. In the seventh paragraph of this chapter the plow bottom is referred to as a three-sided wedge. The mouldboard and upper part of the share form the curved wedge shape part which separates the soil parti- cles while turning them over. For the sake of clearness in this discussion the work of the plow bottom is divided into three parts: first, the share, cutting the furrow sole; second,, the shin, cutting the furrow wall; third, the mouldboard, lifting, stretching, turning and compacting the furrow slice into an inverted position. The relative amount of work that the shin, the mould- board and the share do is exceedingly hard to figure. It is very doubtful whether an absolute center of draft can PLOW BOTTOMS 117 A section of the furrow shown in the illustration on page 116 cut farther forward, showing that the plow bottom has forced the furrow slice to conform to its shape, thereby beginning a stretching operation on the bottom of the furrow. Observe in the illustration on page 116 that after the furrow slice has reached the ground the freshly stretched furrow slice bottom is helping to put pressure against the top. A plow bottom which does not have the proper shape to force the furrow slice against its surface so that the pressure is equal on all parts of the plow bottom. This illustration shows the importance of having a plow bottom adapted to the soil. The shin is doing the greater part of the wor\. 118 THE OLIVER PLOW BOOK The work, of this bottom shows remarkable adaptability to this type of soil. The squeezing, pinching motion of the mouldboard by forcing the furrow slice against the bottom of the furrow is plainly noticeable. This mouldboard is doing more work than the one illustrated on page 120. be determined for all conditions. Enough experimenting has been done to show that the center of draft can be approached closely enough for practical purposes. When once the center of draft has been determined it is obvious that the amount of work being done on all sides of this point must be equal in weight. Measuring the distance from this point to all the extremities of the mouldboard and share will give sufficient measurements to figure the percentages. The result will be close enough for all practical purposes. PLOW BOTTOMS 119 The furrow slice shown in the illustration on page 118 cut farther forward. The plow bottom forces the furrow slice against it in such a way that the complete furrow slice takes on the curvature of the mould- board. This means a rearrangement of the soil particles from the top of the furrow slice to the bottom. Another way for determining the relative draft of the share and mouldboard is to remove the mouldboard from the plow, then start the plow in a furrow the proper width and depth previously prepared with the end of the furrow slice cut squarely, and the furrow wall the depth of the furrow far enough ahead for the experiment. A. dynamometer will show the relative lifting work done by the point and wing of the share. The plow must stop as soon as the earth has been lifted the height of the share. Putting the mouldboard back on the plow, and lifting the furrow slice which has been measured the proper width and cut the full depth until it is ready to drop into position, will obviously determine the amount of work required by the share and mouldboard. Subtracting the difference between this amount and that required by 120 THE OLIVER PLOW BOOK The furrow slice is being picked up and turned over very much as a cake of ice, without any perceptible pulverization of the ground. Observe that the bottom of the furrow slice does not rest against the furrow bottom except the loose particles that have broken off and have fallen down. Observe the center of draft on this plow is lower than the one shown on page 118. the share will give the amount of work done by the mouldboard. Using the entire plow without cutting the furrow wall gives the amount of work required by the shin to cut the furrow wall, the share, the sole, and the mouldboard to crush and invert the furrow. Experi- ments of this kind have been conducted with widely diversified results. A test was made using what is known as the Scotch type of plow bottom. The ground, clay sod, was being plowed six and one-half inches deep and eleven inches wide. The amount of work done by the share was forty per cent, of the total, the lifting and placing by the mouldboard, forty per cent, and cutting the furrow wall by the shin twenty per cent. PLOW BOTTOMS 121 The furrow slice the same as shown on page 120 cut farther forward. This furrow shows no indication of pulverization but a tendency to lift the slice from the start. Another experiment with an entirely different shaped bottom cutting six inches deep and fourteen inches wide revealed the following result. Thirty-three per cent, of the work was done by the share, forty-seven per cent, by the mouldboard, and twenty per cent, by the shin cutting the furrow wall. The type of soil in which the experiment was conducted was a clay loam sod. In both instances the draft of the plow was arranged so that there was no pressure of the landside against the furrow wall. The amount of work required of the landside is solely determined by the hitch. If the hitch is properly made there is little landside pressure because the land suck on 122 THE OLIVER PLOW BOOK A type of mouldboard which breads this wet clay soil into large clods. Notice the blujfness and the effect upon this soil. It ought not require any argument to show that this plow is not adapted to this type of soil. Breaking soil into clods is not plowing. the share and shin cuts away the earth, leaving the land- side free from coming in contact with the furrow wall. However, in actual practice this condition does not pre- vail. It has been found that the pressure of the landside against the furrow bank caused by incorrect hitching increases the total draft of a plow bottom from fifteen to forty per cent., depending upon the kind of soil being plowed and the distance the hitch is away from the center line of draft. This statement with reference to the pressure of the landside immediately suggests the point, why have a landside on a plow if there should be no pressure against the furrow bank ? There must be some means for keep- ing the plow from swerving to one side whenever the share strikes some obstruction that causes a sudden shifting in the center of draft of the plow bottom. For PLOW BOTTOMS 123 In view of the fact that breaking the soil particles is necessary for the proper making of the seed bed, the question often confronts those who have stony ground as to how they can plow so that the bottom will pene- trate the ground immediately after the stone has been passed. The illus- tration shows how one farmer is accomplishing this work- On account of the rapidity with which this type of soil dries out it is highly im- portant that there be the fewest possible unplowed stretches of ground. example — if a plow should strike a snag on the wing of the share the center of draft of the plow is suddenly changed to a point near the wing. The landside press- ing against the furrow wall holds the plow in its true 124 THE OLIVER PLOW BOOK Turning an in-corner has been practiced by farmers who have soils that should not be trampled any more than is necessary in the process of plowing. It is highly important that the furrow be turned so that the ground is plowed properly if the best results are to be obtained from this practice. line until the obstruction is passed and the center of weight returns to its normal position. As a matter of fact, this condition is constantly taking place in the soil. The soil texture changes with every inch of travel and some means must be provided to take care of rapid and continuous changes. The shape and size of the landside have a great deal to do in this con- nection. Obviously there must be enough square inches PLOW BOTTOMS 125 This clay field is being plowed seven inches deep to permit moisture to escape. This field was tiled but on account of the imperviousness of the clay excessive water remains and it is necessary to plow in such a way that there is under -drainage. Contrast this type of plowing with that shown in the illustration below. When plowing sandy loam the great object is to stir the ground for aeration and leave it in such a manner that moisture will not unduly escape, thus the crowning of the furrows, noticeable in the illustration above, is entirely absent and the ground left as level as possible. These two illustrations are good evidences of the fact that plowmakers are striving to build bottoms that will do the soil the greatest possible good. of landside surface to prevent the plow gouging into the furrow wall and also to help keep the plow running level. On breaking plows the shallow furrow requires an ex- 126 THE OLIVER PLOW BOOK This method of laying the furrow when plowing sod insures the fewest possible air spaces and vents for the continued growth of the inverted grass blades. ceptionally long and narrow landside to give the required surface. On stubble and general purpose plows this surface can be acquired by giving more height and not PLOW BOTTOMS 127 One does not often see three different styles of plow bottoms on the same plow. These bottoms are all cutting the same width and the same depth but notice the difference in the delivery of the soil. The front plow bottom is doing the quality of work, this soil requires. The other two are not — the middle bottom doing better work than the rear one. The front bottom is the same as that shown in illustration G; the second, illustration F ; the third, illustration K. Observe in the work °f the front bottom that the soil is completely turned over and well pulverized and that the middle bottom turns the furrow over more completely than the rear one. so much length. In bottoms that are made for deep plowing more attention is given to the height of the landside than to the length because of the greater amount of work being done by the mouldboard. The amount of moisture in the ground, its looseness and compactness, and amount of stubble, trash, roots and sod are determining factors in the draft of plow bottoms. Too much moisture in the ground adds draft in the same manner as not enough moisture. Daily changes in moisture cause great changes in draft. 128 THE OLIVER PLOW BOOK Shallow plowing of sods puts more work on the share and less on the mouldboard. Deep plowing of sod lessens the work of the share and puts more work on the mouldboard. The same is true of stubble. The curvature of the upper part of the share, the mouldboard, and the angle of the mouldboard to the furrow slice have to do with the pulverizing qualities of the bottom as well as the draft. The increase in the speed of a plow in dry, hard plowing aids materially in better pulverization, but while it is doing better work it increases the power re- quired. A plow bottom shaped to do the proper work at a speed of two and one-half miles an hour will throw the dirt from two to three times as far when travelling at twice that rate of speed. CHAPTER XIII Plow Bottom Metals THE farmer is often in doubt as to whether he should use a chilled or steel plow. A knowledge of chilled and steel metals as used in plows will enable a farmer to determine for himself which type of plow he needs. In steel plows of the best grade, the principal wearing parts, the mouldboards and shares, are made from what is known as soft center steel. This steel is composed of three layers fused together. The two outside layers are very high carbon to insure hardness. An extra hard finish or temper is necessary to make the plow scour. The center layer is of low carbon to impart toughness to prevent the breaking of the brittle outside layers. Steel plows thus made are successful for use in soils for which they are adapted. The mouldboard of a steel plow of the type described is only a quarter of an inch thick and the grinding and polishing necessary to finish the surface added to the natural wear, of course, wear away much of this thickness so that sometimes the soft center becomes exposed and the plow will no longer scour. For this there is no remedy and a new part is necessary. While steel plows are, as a rule, lighter in weight than the chilled, when it comes to the matter of draft the chilled plow is by far the lightest in any or all soils for which it is adapted. The draft of a plow is determined not so much by the shape of its mouldboard and style of 130 THE OLIVER PLOW BOOK share, as by the scouring qualities of the metal which enter into its construction. As a matter of fact, tests in draft of plows have been made in the agricultural departments of universities. These tests have shown that chilled plows are lighter in draft. No process has yet been invented whereby steel can be tempered hard enough to prevent sand and stones from deeply scratching the surface. Any farmer who has land that is sandy in places knows, if he uses a steel plow, that it refuses to scour after leaving the sandy parts and enters the black or sticky land. This is caused by the sand scratching the steel, leaving a feather edge that ruins the dirt polish and makes an obstruction to stop the shedding of the dirt. Anyone who has never had this feature called to his attention can observe the phenomenon by examining his plow the next time he plows a piece of land in that condition. This peculiarity of steel makes a steel plow an exceedingly poor implement to use in any soil that has sand, gravel or stones in it, because the plow wears out too soon. It is like using a razor to sharpen lead pencils — too costly. There is a type of land that steel plows turn to good advantage and much better than chilled plows can, in fact, where chilled plows will not work at all. Light soils, loams free from sand, gravel, or stones, and black, waxy dirt can be handled most successfully with the steel plows, because they have in them the properties necessary to make the dirt polish on the mouldboard without scratching it. Wherever this condition prevails, steel plows are the most successful, but when grit is present the wear on the thin layer of hard steel on the PLOW BOTTOM METALS 131 The top of a steel share is perfectly smooth and has as uniform hard- ness as it is possible to make. Plow gunnels with and without a piece of steel welded on the bottom for reinforcing the point. This metal is of the proper carbon content to help keep the point from wearing upward on the bottom. It is illustrative of the efforts put forth by plow makers to make steel shares as durable as possible. The projection on the edge of the gunnel gives a wider welding surface thereby making the share stronger. The bottom side of the share showing the position of the extra piece of steel on the finished product This gives strength and additional wear. 132 THE OLIVER PLOW BOOK surface soon exposes the center which is so soft that it will not scour in any soil. Chilled plows are constructed by an entirely different process. When the mouldboard is properly made it has a flinty hardness that never has been duplicated in steel. This hardness enables a chilled mouldboard to much better withstand the scratching of sand, gravel, stones, etc. As a matter of fact, there is no scratching that will affect the scouring qualities of properly chilled metal. As a result the more a chilled mouldboard is operated in sandy soil the smoother it becomes, and the higher polish it takes. Long experience has shown that used plows have a better polish than can possibly be put on in the factory. This peculiarity of chilled metal makes chilled plows scour better in all kinds of sandy, gravelly, stony, heavy clay soils, and the silt loams that contain silica, potash, lime, iron and aluminum oxide. The chill, as plowmakers call the term of hardening, crystallizes the metal so that the grain is edgewise of the mouldboard instead of lengthwise. This means that the dirt in shedding passes over the ends of the crystals. The ends of the metal crystals furnish the surface for scouring. For this reason chilled mouldboards are very hard to wear out. They often wear twenty years. Instances are known where they have worn fifty years. Chilled mouldboards have been used until the edge has been worn to the thinness of a piece of paper and sharp enough for a keen cut knife. The thickness of a chilled mouldboard is about % to J/^ of an inch. One-quarter of an inch of this entire thickness is made of chilled metal, consequently, a mouldboard will wear and scour until the entire thick- ness of the chilled portion is worn away. When this is PLOW BOTTOM METALS 133 The shin and point of this bottom show the effect of sand upon steel bottoms. This sort of ground causes a steel bottom to wear out very quickly. Chilled metal. This sample of chilled metal showing the crystals turned on edge explains why sand does not wear away chilled metal as it does steel. The dirt, passing across the ends of the crystals, has a tendency to polish chilled metal rather than to wear grooves in it. 134 THE OLIVER PLOW BOOK compared with the thin layer of ^" of steel on the soft center steel mouldboard, one can readily see that a chilled mouldboard will outlast three steel. This fact is what gave rise to the statement that one chilled plow will outwear three steel in gritty conditions. Properly chilled plows are not affected by rust. The iron being needle crystal in form merely corrodes on the end of the needle. The operator can scour a chilled plow that has been exposed to the deteriorating weather conditions for a long time in a few feet of travel with the bottom in the ground. This feature of chilled plows is in great contrast to steel plows which rust so easily that the rust occasioned by a few days' exposure often makes them hard to scour. From the foregoing discussion on chilled and steel plow bottoms, it is obvious that many farmers can use both types of plows to good advantage, and where it is possible to interchange the steel wearing parts with chilled, the advantage is double because of the saving in expense. Oftentimes it is necessary to plow in the summertime when the ground is hard and dry. The chilled share being much more resistant to the hard earth will enable a plowman to do better work by using chilled shares. Experiments have been tried many times to determine the amount of wear of chilled and steel shares. We quote one experiment that was tried for this purpose and the result. A two-bottom tractor plow was equipped with a chilled and a steel share of the same size and type, one bottom being equipped with a steel share and the other with a chilled share. The ground in which the experiment was tried was a sandy soil, very hard, with PLOW BOTTOM METALS 13* This piece of chilled metal was buried eight years. The rusty surface was scratched away with the back, of a k.nife blade, revealing a perfectly smooth and unpitted surface beneath. The peculiarity of the way each metal wear s is plainly discerni- ble. The points of these shares are illustrated on page 136. 136 THE OLIVER PLOW BOOK vu> CU\LYX£> Steel New Used 8 Hours some stones in it. The test was made the first of September. The steel share was only used eight hours and the chilled share fifty-one hours, thus showing that the chilled share in this type of ground would outlast six steel shares. CHAPTER XIV Scouring Troubles ANY man who has ever operated a plow knows what failure to scour means. A plow bottom must scour if the best work is to be done. The reason why plows fail to scour is very seldom the same in any two fields, yet, underlying all these causes are five fundamental facts. The first and most common cause is the lack of an earth polish; the second, improper plow adjustment; third, soil conditions; fourth, soft spots or inequalities in the mouldboard; and fifth, the shape of the bottom with relation to the soil texture. The easiest way to overcome the lack of an earth polish is to take the plow into hard ground and operate it until this polish appears. A new plow coming from the fac- tory is always covered with varnish or lacquer. This should be removed before attempting to make the plow scour. In removing the varnish it is better to use some varnish remover preparation or strong lye solution. Never use a sharp, steel instrument because it is very apt to scratch the mouldboard. Whatever preparation is used none of it should be left on the plow bottom any longer than necessary to clean the bottom because a solution that is strong enough to quickly remove the lacquer will have a tendency to pit the surface if left on for any length of time. The safest rule is not to leave the bottom from the start to the finish of the cleaning. 138 THE OLIVER PLOW BOOK When a plow mouldboard becomes pitted it must be polished to the depth of pitting before it will scour. If plows have this high earth polish and fail to scour the trouble can nearly always be traced to soft spots in the mouldboard, or to the soil itself. Assuming that the mouldboard does not contain soft spots and the soil does not contain enough silicon to scratch the mouldboard, the trouble may be caused by the plow not runfting in a true line of draft, or the soil is too loose for the proper amount of pressure to cause the mouldboard to shed properly, or it may be a combination of all these causes. Side draft causes the mouldboard to work out of its normal position, thus making unequal pressure of the earth on the mouldboard. The remedy for this trouble is to adjust the hitch so that the plow bottom works in its normal manner. Whenever a plow fails to scour it is always advisable first to be sure that the plow is running correctly. If this does not remedy the trouble lowering the plow an inch or two will put more pressure against the mould- board, thus forcing off the earth which may be clinging to the bottom. It may be necessary to operate at this extra depth long enough to put on a new polish. Often times lowering the bottoms and travelling a distance of fifteen to twenty feet will suffice. Occasionally soils which scour readily have spots in them that cause the plow to stick. These spots are nearly always the result of a change in the soil texture. That is, the spots where the plow sticks are caused by the soil being looser. If the driver will watch these places very carefully he can frequently cause the plow to scour readily by increasing the speed when passing SCOURING TROUBLES 139 A type of soil in which mouldboard plows were never known to scour. Observe the soil sticking to the handle and the beam. This soil is of that type in which the soil particles have greater affinity for other substances. Plow mouldboards covered with plaster of Paris and hog hides have been known to turn this soil much more successfully than any metal. Sectional view of ground plowed in the above manner. The ground is merely pushed to one side and the top looks as though it might have been broken up with any ^'nm$m Observe the plow is scouring all the time and that the soil has the ap- pearance of being pulverized and well turned even though growth of alfalfa was vigorous. reputable plow manufacturer at once and have him send an expert to look over the situation. All plow bottoms are designed for the express purpose of invert- ing the earth. It is not possible to design any one type 144 THE OLIVER PLOW BOOK of mould that will turn all the different soils equally well. The fact that clay soils hold together means that a plow to successfully turn and pulverize them must not have so bluff a mouldboard as is required for turning loose, sandy soils. The tendency of clay particles for holding together removes the necessity for as much bluffness and curvature in the mouldboard. As soils vary from one extreme to the other, so must builders make plow bottoms to meet these variations. As a matter of fact, plow manufacturers have a large variety of plow bottom combinations in order to prop- erly plow soils of different textures. It is a peculiar fact that in the waxy soils of Texas, plow mouldboards have been made of steel, iron, glass, brass, aluminum, plaster of Paris, and hog hides. The peculiar part is that the plaster of Paris and hog hide mouldboards worked more successfully in these soils than any other type of mouldboard that has been invented. Whether the shape of a mouldboard has everything to do with its scouring, assuming that it has. the proper degree of hardness, is a question open to debate. The experiences gleaned from trying to develop a mould- board that would work successfully in the waxy soils of Texas developed so many sizes, styles and shapes of plow bottoms that the plow bottom graveyard is full to overflowing. These experiences must be regarded as very strong evidence that something is required other than the shape of the mouldboard and the material from which it is made. SCOURING TROUBLES 145 A never failing way to determine the soft spots in a mouldboard is to take an old file and break, it so that a sharp edge results. Run this lightly over the mouldboard. The file will slide smoothly over the hard parts. It will stick to the soft spots. Plow manufacturers are always desirous of having their plows give satisfaction. After a little exper- ience of this kind it will be easy to detect soft spots in mould boards from their cloudy appearance. Soft spots never take the high polish that the rest of the board does. The reason given for the success of the plaster of Paris board is that the plaster wears away with the earth. This demonstrates that the adhesive force between the earth and the plaster is greater than the cohesive force of the plaster. It also demonstrates that the cohesive force of the earth is greater th-an that of the plaster of Paris. 146 THE OLIVER PLOW BOOK The plaster wears away rapidly and the farmer is obliged to recoat his mouldboard often — sometimes as often as every night. Considering that Texas farmers have different sizes and shapes of plow bottoms, it is plainly evident that the shape of the bottom does not control its scouring qualities. The revolving disk is the only type of steel plow at the present time that is regarded as handling this soil successfully, but the disk plow does not scour in these soils, showing that the ad- hesive force of the steel disk and the earth is greater than the cohesive force of the earth and also that the co- hesive force between the two is greater than the adhesive force of the earth particles. If it is a question of constant pressure of the soil against the mouldboard, it is necessary, then, in the design of a mouldboard to shape it to interfere as little as possible with the crumbling of sticky soils when turning them over. It is far from easy to design a plow bottom that will always do these things satisfactorily. The Texas illus- tration must be regarded as conclusive evidence that the shape of the mouldboard is not the only factor to be taken into consideration. The material from which the mouldboard is made and the way it is made often have more to do with the success of the bottom than its shape. Very frequently a mouldboard that from all standpoints of theory should do a better job than another type of bottom does the poorer quality of work simply because the mouldboard fails to scour. Another side in scouring that is little known and has received but spasmodic attention is the effect of heat upon metal mouldboards. SCOURING TROUBLES 147 One time a plow bottom designer was trying out a bottom in sticky soil. The field was wet on one side and dry on the other. The day was fearfully hot. In the morning it was observed that the plow was scouring successfully in the wettest and driest portions of the field but where the two came together the plow refused to scour on going into the wet portion and also refused to scour on coming out. At noon the plow bottom was cleaned and left standing where the sun had a good opportunity to thoroughly heat it. The plow bottom became very warm and the first two rounds in the after- noon the plow scoured. After that the designer en- countered the same trouble he had experienced in the morning. It is a matter of plow history that a Texas farmer devised a pan arrangement back of the mouldboard, well down towards the share, to hold burning corncobs. The difficulty experienced in this device was the lack of uniform heat on all parts of the plow bottom. Those who witnessed the demonstration maintained that the mouldboard scoured where the temperature was hot enough, but failed to scour on other sections of the bottom. There may be more in this theory than some of us think at the present time because it is a well known physical fact that heat is the best agent for separating molecules combined by adhesive force. Oftentimes failure to scour cannot be attributed to any one cause. It may be a combination of two, three, or more of the conditions mentioned in the second para- graph. The operator must act in cases of scouring troubles very much like a physician diagnosing compli- cations in a case of illness, and then apply the proper remedies for each trouble. 148 THE OLIVER PLOW BOOK Enough has been said to show that a dull, or incor- rectly shaped share can do irreparable damage, and the operator never discover the source of the trouble unless he takes time to investigate. Incorrect hitching and a dull share combined cause a plow to do so many erratic things that the share symptom is often overlooked in seeking to rectify the trouble by hitch adjustments alone. CHAPTER XV Setting the Share on the Plow KNOWING how to drive the team properly and make the hitch correctly are two points that deter- mine good plowmanship. The other one is to know that your plow bottom is in the right condition. The share is the vital part in this work. If the operator is positive the share has the correct shape for land suck and penetration, he has little to worry about in making the plow work successfully. A plow bottom operating correctly cuts all the furrows the same width, the same depth, and runs level. If the plow is not doing this naturally, some- thing is wrong. The first thing to investigate is the share. If the bottom has a tendency to rise when the hitch is made where it always has been in the past for plow- ing that depth, the plow share is worn rounding on the under side, giving the share a sled runner effect. The tendency is to work out of the ground instead of into it. Sharpening the point is necessary to rectify this trouble. If the furrow bottom is uneven and full of gouged places, the plow bottom is running on its point. If the hitch is the same as it has been in the past for plowing at this depth, the trouble is that the point of the share is bent downward too much, causing it to move forward with a jumping motion. This can only be rectified by putting a gradual slope on the point. 150 THE OLIVER PLOW BOOK In shaping the point of a plow share the greatest care should be ex- ercised to see that it has a gradual wedged shaped slant. One of the difficulties encountered when carelessly sharpening shares is to put the point of the share over the edge of the anvil, then hit it a blow with a hammer. The result is worse than the equivalent of a dull share. Instead of the plow going in deeper as intended, it gouges along the ground and increases the draft of the plow. The illustration shows the proper angle and shaping of the point. The wing of the share when properly sharpened, rests on a straight edge with the point. The edge of the throat is slightly raised from the straight edge. This means that when the plow is operating in the ground the point is as much low as the throat is high on the straight edge. SETTING THE SHARE ON THE PLOW 151 • a -2 -2 1S1 o -if C C co ■< *c "S 5 ■« ?i « 1 C u as c K 3 w CO .51 to O H a s ^■8 5b -At" a ■*- 3 •= w •— -q -o v. C « ^ "5 .5 S o § IH 1 "a 3 to g "S .£■£ •2"° v. e * * is «. 152 THE OLIVER PLOW BOOK If the plow bottom has a tendency to pull down on the point so as to bear heavily on the land wheel and lightly on the furrow wheels, the share is bent upward too much on the wing. To remedy this the wing of the share must be lowered. If the plow has a tendency to bear down heavily on the furrow wheels and not on the land wheel, there is too much dip or suck in the wing of the share. This must be rectified by raising the cutting edge of the wing. The length of time that the bearings and axles of wheel plows wear, providing they are kept properly greased, is largely determined by the correct adjust- ment of the plow bottom. For this reason, as well as that of good plowing, plow shares should be kept sharp and adjusted correctly. These are delicate operations and a competent smith or plowman should be consulted if the operator is not absolutely certain which course to pursue. The share of a walking plow has more wing than the riding plow. This additional wing surface is necessary as a bearing to keep the plow running level. On sulky plows the wheels carry this weight. Hence, when the shares of wheel plows are properly sharpened, only the cutting edge comes in contact with the ground. The effect of the wrong set on a share is immediately notice- able in a walking plow and is identical with that of the wheel plows. The operator has to stand the brunt of the incorrect adjustment that the wheels and frame of wheel plows sustain. When one remembers that the point of the share extends a slight distance landward from a line parallel with the landside to make it hold the land, and slightly downward below a line parallel with the bottom of the SETTING THE SHARE ON THE PLOW 153 landside to hold it in the ground, and the wing of the share with edge shaped to keep the bottom working level, he will have little difficulty in setting a share on the plow bottom. Shares and bottoms made by different manufacturers have differences in shapes, but the general principle is the same. CHAPTER XVI Sharpening Soft Center Steel Shares THE majority of steel shares are made of soft center steel, a term applied to the use of a layer of low carbon steel between two of high carbon. The soft center steel is by far the most common steel share in use and requires a particular treatment in sharpening because of the peculi- arity of wear upon it. Most of the wear on the share takes place on the underside, hence the lower layer of high carbon steel wears away faster than the upper one. This must be observed very carefully in sharpening the share. In heating, care should be taken that only the portion of the share which is to be pounded out is heated. This can be done by laying the share flat with the edge over the center of the fire and filling up the underside with green coals. This keeps the greater part of the share cool, thus preserving its shape. The common mistake is to put the share in the fire in a vertical posi- tion with the edge down. This heats too much of the share and causes it to warp and spring out of shape. The pounding should be done from the upper side with the bottom of the share flat on the anvil. This keeps the cutting edge down and works the hard steel of the upper surface over the soft steel in the center, thus pre- serving for the share a hard cutting edge. Since shares receive the most wear on the under side, pounding the share on this side exposes the soft center steel and has a tendency to work the cutting edge out of shape. 56 THE OLIVER PLOW BOOK A picture of a soft center steel share pounded on the upper side. The edge has the appearance of being somewhat rough but the hard steel was worked down over the edge. Sometimes in heating soft center steel shares the layers of steel are loosened. Wherever this happens pounding the share on the upper side keeps it from wearing away. Soft center steel share pounded on the under side when being sharpened. Notice that the hard steel on the surface has been broken away on the edge and on the point. This is caused by improper heating when sharpening and pounding the share on the under side. A little practice in sharpening soft center steel shares in the correct way and an under- standing of how to set them on the plow will eliminate a great deal of the difficulty farmers experience in the operation of the plow. After the point has been hammered on the anvil to the proper shape, if necessary, a piece of steel can be welded to the top of the point. Care should be taken in doing this work not to dent the share when hammering it out as this would spoil its scouring qualities. SHARPENING SOFT CENTER STEEL SHARES 157 To temper the share properly after it has been ham- mered out requires uniform heat. The right heat is a dull cherry red, a temperature of approximately 1 472° F. One of the most successful methods of tempering is to slowly draw the share through the fire with the cutting edge down until the edge has been heated to the proper color. Then draw the share from the fire, put the point far enough into the ground to hold up the share, and let it stay there until it cools. CHAPTER XVII Sharpening Crucible Steel Shares CRUCIBLE steel shares are made of one piece of steel. They cannot be tempered so hard as soft center steel because tempering makes them too brittle and thus subject to easy breakage. Ground that sheds easily can be successfully plowed with a crucible share. Crucible steel shares can be sharpened exactly the same as soft center steel shares, or they can be treated according to the old custom of pounding the share on the reverse side. However, there is less danger of misshaping the edge of the share if it is pounded on the upper side. 158 CHAPTER XVIII Sharpening Chilled Shares CHILLED shares are made in moulds the same as chilled mouldboards. On account of the nature of the iron they cannot be heated and drawn out by pound- ing as can steel shares. When it becomes necessary to sharpen chilled shares they must be ground on the upper side on an emery wheel or grindstone until a bevel edge appears. 159 CHAPTER XIX The Rolling Coulter THE purpose of the rolling coulter is to cut the stubble and trash into lengths the width of the furrow and leave a smooth furrow bank. On account of the great difference in soil texture and the varieties of trash dif- ferent adjustments are necessary to bring about this result. To make the furrow bank smooth the rolling coulter must be set to the land far enough away from the plow shin and deep enough in the ground to prevent the shin of the plow from digging into the furrow bank made by the rolling coulter. In ordinary conditions the coulter set to cut a furrow }/±" to ^g" wider than the, plow bot- tom will suffice, but by no means can anyone assume that this is a set rule to follow. Set the coulter so that it accomplishes the result intended. One must remember when setting a coulter to properly cut the furrow bank that, if the coulter, when set, is not running parallel with the landside of the plow, the plow is out of adjustment and the bottom must be correctly adjusted before the rolling coulter can be finally set. The depth at which the rolling coulter operates must be determined solely by conditions. In cutting trash the coulter should make with the surface of the ground a condition similar to a shear cut, using the ground for one edge of the shear. In order to produce this shear cut with the rolling coulter it is necessary to have the coulter high enough to force THEIROLLING COULTER 161 This illustration shows the effect of a plow out of adjustment on the rolling coulter. The rolling coulter is always pulled in a straight line of draft. The bottom as is illustrated by the landside shows that it is working out of its true line of draft. The clods and earth on the edge of the furrow bank are telltale evidences of the wrong plow adjustment. 162 THE OLIVER PLOW BOOK the trash down and under. The coulter cannot do this if it is set deep enough in the ground for the downward motion at the cutting edge to be prac- tically straight. For this reason the safest rule is to set the coulter deep enough to cut the trash without clogging and shallow enough to cut the trash without riding over part of it. When operating the plow in hard ground the coulter set high and as far back as possible gives the plow point a chance to penetrate the ground first. The plow bottom sucks its way into the ground. The rolling coulter must be forced into the ground. If the coulter is placed ahead of the plow point part of the suction of the bottom will be utilized in pulling the coulter into the ground. If the plow point penetrates first it has the advantage of the weight caused by deeper penetration to hold the coulter in the ground. In plowing stony ground the coulter set well ahead of the point and very low prevents stones from lodging between the coulter blade and the plow bottom. A little study of these fundamentals will soon point the way for properly adjusting the coulter. The Jointer The purpose of the jointer is to turn a small furrow on top the furrow slice so that when this slice is inverted the trash, stubble, sod, etc., may be turned to the bottom of the furrow. The adjustment of the jointer is very much simpler than that of the coulter. It should be set so that the furrow it turns should rest upon the larger furrow slice THE ROLLING COULTER 163 When the coulter is properly set the furrow wall is smooth with little or no dirt on the unplowed ground next to the furrow wall. The clean cut furrow slices and the absence of protruding stubble are the benefits of a correctly set combined rolling coulter and jointer. 164 THE OLIVER PLOW BOOK Observe the jointer turning a little furrow into the right-hand corner of the big furrow bottom. This is necessary for ideal plowing. THE ROLLING COULTER 165 in such a way that it will roll into the lower right hand corner of the furrow when the slice is being inverted. For the most part this point is slightly ahead of the point of the plow and on the unplowed land 34' to %" from the shin of the plow. These measurements are by no means fixed. The adjustment must be made to bring about the desired results. The jointer cannot be used by itself in very trashy ground because the trash will catch on the point of the shin and clog the throat of the plow. This fact led to the use of the combined rolling coulter and jointer, the adjustment of which is practically the same as that of the rolling coulter and jointer separately. The Combined Rolling Coulter and Jointer The combined rolling coulter and jointer is a recent improvement in plows and has made possible the suc- cessful covering of weeds and trash in the lower right The combined rolling coulter and jointer is one of the greatest helps for plowing properly. 166 THE OLIVER PLOW BOOK hand corner of the furrow where they interfere very little with the upward trend of moisture and thus rapidly help make humus out of the weeds. The combined rolling coulter and jointer is the only attachment that has been invented for use with plows which absolutely assures that all kinds and sizes of trash will be buried deep enough in the ground for the suc- cessful eradication of insects which plowing puts out of business. Whatever time of the year it may be neces- sary for plowing it is always advisable to have that plow equipped with a combined rolling coulter and jointer and to see that all trash is buried on the bottom of the furrow. CHAPTER XX The Tractor Plow Hitch BEFORE one attempts to adjust a plow he should know the physical laws that govern the operation of plows. Otherwise he is groping in the dark. It has been the experience of a great many plow experts that the prin- ciples or physical laws underlying the working of plows are not generally understood. For this reason this chapter will treat plow adjustments from the theoretical side (which after all controls the practical), rather than enter into a discussion of how the operator should change the hitch to produce certain results. Another reason for treating the matter from the physical law side is that specific instructions sometimes produce the opposite from the intended results. This happens quite often when instruction books are followed. No writer of instructions can call before his mind all the different conditions that must be met; consequently the best intentions cause trouble by the reader's inability to diagnose conditions correctly. The draft laws that control the operation of tractor plows are the same for wheel and walking plows. How- ever, different adjustments are necessary to make these different types of plows conform to the basic law govern- ing proper adjustments. This law stated very specifi- cally is: The shortest distance between two points is a straight line. In tractor plow adjustments one of these points is the "center of power" of the tractor, usually regarded as a point on the rear axle at equal distance 168 THE OLIVER PLOW BOOK from the drivers. The other point is the "center of draft" (also called the center of weight or the center of resistance) of the plow. A straight line between these points is the "line of draft." The line between these two points is theoretically always straight. Being obliged to turn the front tractor wheels toward the plowed ground indicates that the draft of the plow is pulling the front of the tractor in the opposite direction. This is hard on both the plow and the tractor. The center of draft of the plow is an imaginary point in the plow base or bottom from which a single force pulling straight ahead and parallel to the furrow wall will cause the plow to work correctly with the minimum effort. This point is usually placed from 12 to 15 inches back from the share point, 2 inches up from the furrow sole and 3 inches from the furrow wall. One must remember that this point is not fixed but con- THE TRACTOR PLOW HITCH 169 stantly moves from side to side and up and down on account of the variations in shapes and the intensity of the pressure of the earth against the bottom. But for the sake of explaining the principle we will assume that this point is correct. In actual practice a slight variation does not materially affect the working of the plow. Being obliged to turn the tractor in this direction shows that the draft of the plow has a tendency to pull the wheels toward the plowed ground. This puts enormous end-thrust on the front of the tractor, and demands additional power for operation. It is impossible to pull a plow in the true line of draft because the hitch would be below the surface of the ground. The fact that the power cannot be operated in a line parallel with the landside through the center of draft of the plow necessitates two lines of draft. These two 170 THE OLIVER PLOW BOOK lines — one a vertical line of draft (or force) tending to pull the plow out of the ground and the other, the line of side draft, which has to do with keeping the plow oper- ating straight ahead — determine plow adjustments. The line through which these forces neutralize (or the resultant force) is the true line of draft from a practical standpoint. All plow adjustments must be made to keep this line straight, because this line will straighten theoretically regardless of how the plow or the tractor operates. When we understand these laws and what is necessary to keep the line between these two points straight, that is, between the center of power and the center of draft, we can readily see why it is necessary to have the plow beams and a vertical adjustment to take care of the penetration of the plow, as well as a horizontal adjust- ment to take care of the side draft. In Fig. 5 is illustrated the vertical line of draft. C is the center of draft of weight. CX is the theoretical line of draft. B represents the center of power of the tractor. BGC then represent the line of draft passing through the clevis on the front of the beam of the plow at G. If the line BGC were angled as BHC and the resistance at point C required more power than the force necessary to straighten the line, it is evident that the line BHC would assume the position BGC before the plow would move. Hence the bottom would rise until BHC reached the position BGC. Obviously this would lessen the depth of the plow regardless of the fact that there may be a wheel at the rear and one at the front. If the front wheel happened to be the controlling factor of a power lift, the lift would refuse to work because of the lack of weight to hold the THE TRACTOR PLOW HITCH 171 rrl Nov (Q / / / / 1 II