LIBRARY, CAMPUS . A104-529-7,000-L180 TEXAS AGRICULTURAL EXPERIMENT STATION} ‘(iv-m A. .$@ {IjQII " COLLEGE BULLETIN NO. 39s I’ u": JEXAB Lmaaa? DIVISION OF AGRONOMY E F ERTILIZERS FOR RICE 1N TEXAS AGRICULTURAL AND MECHANICAL COLLEGE OF TEXAS T. O. \VALTON, President STATION STAFF’; ADMINISTRATION: A. B. CDNNER, M. S., Director R. E. KARPER, M. S., Vice-Director J. M. ScRAEDEL, Secretary M. P. HoLLEMAN, JR., Chief Clerk J. K. FRANckLow, Assistant Chief Clerk CHESTER HiGGs, Executive Assistant C. B. NEBLETrE, Technical Assistant CHEMISTRY: G. S. FRAPS, Ph. D., Chief; State Chemist S. E. AsBURY, M. S., Assistant Chemist E. C. CARLYLE, B. S., Chemist WALDo H. WALKER, Assistant Chemist VELMA GRAHAM, Assistant Chemist . S. OSGOOD, S., Assistant Chemist T. L. OGIER, B. S., Assistant Chemist J. G. EvANs, Assistant Chemist _ ATRAN J. STERGES, B. S., Assistant Chemist G. S. CRENSHAW, A. B., Assistant Chemist JEANNE M. FUEcAs, Assistant Chemist _ HANs PLATENiUs, M. Sc., Assistant Chemist HORTICULTURE: IIAMiLToN P. TRAUB, Ph. D., Chief i, Berry Breeder RANGE ANIMAL HUSBANDRY: J. M JoNEs, A. M., Chief; Sheep and Goat Investigations J. L. LUSH, Ph. D., Animal Husbandman; Breeding Investigations STANLEY P. DAvis, Wool Grader ENTOMOLOGY: F. L. TI-I0MAs, Ph. D., Chief; State Entomologist H. J. REINHARD, B. S., Entomologist R. K. FLETCHER, Ph. D., Entomologist . L. OWEN, JR., M. S., Entomologist RANK M. HULL, M. S., Entomologist . C. GAINEs, JR., M. S., Entomologist . J. TODD, B. S., Entomologist . F. BIBBY, B. S., Entomologist . E. McGREcoR, JR., Acting Chief Foulbrood Inspector o MAcKENsEN, Foulbrood Inspector ONOMY: . B. REYNOLDS, Ph. D., Chief . E. KARPER, M. S., Agronomist; Grain Sorghum Research C_. IVIANGELSDORF, Sc. D., Agronomist; in charge of Corn and Small Grain Investi- 5 wmo~mg A ca wmw ations D. . KILLOUGH, M. S., Agronomist; Cotton Breeding H. E. REA, B. S., Agronomist; Cotton Root Rot Investigations W. E. FLINT, B. S., Agronomist B. C. LANGLEY, B. S., Assistant in Soils PUBLICATIONS: A. D. JAcKsoN, Chief VETERINARY SCIENCE: *M. FRANcIs, D. V. M., Chief H. SciiMIDT, D. V. M., Veterinarian F. E. CARROLL, D. V. M., Veterinarian PLANT PATHOLOGY AND PHYSIOLOGY: J. J. TAUBENHAUS, Ph. D., Chie W. N. EzEKIEL, Ph. D., Plant Pathologist and Laboratory Technician W. J. BAcII, M S., Plant Pathologist J. PAUL LUsK, S. M., Plant Pathologist B. F. DANA, M. S., Plant Pathologist FARM AND RANCH ECONOMICS: L. P. GABBARD, M. S., Chief W. E. PAULsoN, Ph. D., Marketing Research Specialist C. A. BoNNEN, M. S., Farm Management Research Specialist _ V. L. CoRY, M. S., Grazing Research Botanist J. F. CRIswELL, B. S., Assistant; Farm Records and Accounts **J. N. TATE, B. S., Assistant; Ranch Records and Accounts RURAL HOME RESEARCH: JEssIE WRITAcRE, Ph. P, Chief MAMIE GRIMEs, M. S., Textile and Clothing Specialist _ EMMA E. SUMNER, M. S., Nutrition Specialist SOIL SURVEY: **W. T. CARTER, B. S., Chie E. H. TEMPLIN, B. S., Soi Surveyor T. C. REITcR, B. S., Soil Surveyor L. G. RAcsDALE, B. S., Soil Surveyor BOTANY: ———————i-, Chief SIMoN E. WOLFF, M. S., Botanist SWINE HUSBANDRY: FRED HALE, M. S., Chief DAIRY HUSBANDRY: O. C. COPELAND, B. S., Dairy Husbandman POULTRY HUSBANDRY: R. M. SHERWOOD, M. S., Chief ***AGRICULTURAL ENGINEERING: MAIN STATION FARM: G. T. McNEss, Superintendent APICULTURE (San Antonio): H. B. PARKS, B. S., Chief A. H. ALEX, B. S., Queen Breeder FEED CONTROL SERVICE: F. D. FULLER, M. S., Chief . D. PEARcE, Secretary . H. RocERs, Feed Inspector . H. W0oD, Feed Inspector . L. KIRKLAND, B. S., Feed Inspector . D. NORTHCUTI‘, JR., B. S., Feed Inspector IDNEY D. REYNoLDs. JR., Feed Inspector P. A. MooRE, Feed Inspector mégéwm SUBSTATIONS No. 1, Beeville, Bee County: R. A. HALL, B. S., Superintendent No. 2, Troup, Smith County: P. R. JoIINsoN, B. S., Act. Superintendent No. 3, Angleton, Brazoria County: R. H. STANsEL, M. S., Superintendent No. 4, Beaumont, Jefferson County: . H. WYCHE, B. S., Superintendent No. 5, Temple, Bell County: HENRY DUNLAvY, M. S., Superintendent B. F. DANA, M. S., Plant Pathologist H. E. REA, B. S., Agronomist; Cotton Root Rot Investigations SIMON E. WOLFF, M. S., Botanist; Cotton Root Rot Investigations No. 6, Denton, Denton County: P. B. DUNKLE, B. S., Superintendent No. 7, Spur, Dickens County: R. E. DIcKsoN, B. S., Superintendent W. E. FLINT, B. S., Agronomist No. 8, Lubbock, Lubbock County: D. L. JoNEs, Superintendent FRANK GAINEs, Irrigationist and Forest Nurseryman No. 9, Balmorhea, Reeves County: J. J. BAYLEs, B. S., Superintendent No. 10, Feeding and Breeding Station, near College Station, Brazos County: R. M. SHERWOOD, M S., Animal Husband- man in Charge of Farm L. J. McCALL, Farm Superintendent No. 11, Nacogdoches, Nacogdoches County: H. F. M0RRIs, M. S., Superintendent **No. 12, Chillicothe, Hardeman County: J. R. QUINBY, B. S., Superintendent **J. C. STEPHENS, M. A., Junior Agronomist No. 14, Sonora, Sutton-Edwards Counties: W. H. DAMERoN, B. S., Superintendent E. A. TUNNICLIFF, D. V. M., 1W. S., Veterinarian V. L. CoRY, M. S., Grazing Research Botanist **O. G. BAscocK, B. S., Collaborating Entomologist O. L. CARPENTER, Shepherd No. l5, Weslaco, Hidalgo County: W. H. FRIEND, B. S., Superintendent Si-IERMAN W. CLARK, B S., Entomologist W. J. BACH, M. S., Plant Pathologist No. 16, Iowa Park, Wichita County: E. J. WILsQN, B. S., Superintendent _ J. PAUL LUsK, S. M., Plant Pathologist Teachers in the School of Agriculture Carrying Cooperative Projects on the Station: G. W. ADRIANcE, M. S., Associate Professor of Horticulture S. W. BILsING, Ph. D., Professor of Entomology _ V. P. LEE, Ph. D., Professor of Marketing and Finance D. ScoATEs, A. E., Professor of Agricultural Engineering _ _ H. P. SMITH, M. S., Associate Professor of_ Agricultural Engineering R. H. WILLIAMs, Ph. D., Professor of Animal Husbandry A. K. MAcKEY, M. S., Associate Professor of Animal Husbandry J . S. IVIOGFORD, M. S., Associate Professor of Agronomy F. S. JAM1s0N, M. S., Associate Professor of Horticulture TAs of June 1, 1929. *Dean, School of Veterinary Medicine. **In cooperation with U. S. Department of Agriculture. with‘ nnnnnrofinn with Hm Qnlwrml nf Anrinnltnre. Experiments with fertilizers 0n rice at Substation N0. 4, Texas Agricultural Experiment Station, Beaumont, Texas, show that the soils responded t0 nitrogen and phosphoric acid, but nitrogen was needed more than phosphoric acid. During the thirteen years of the experiment, the application of 100 pounds of sulphate of ammonia per acre made the largest average yield of rice, 2,353 pounds per acre, or 553 pounds per acre more than the yield of rice on unfertilized soil. This was the most profitable treatment, making an average profit of $9.65 per acre for the thirteen years of the experiment and $4.55 per acre a year during the last five years. Cottonseed meal and manure were not as good sources of nitrogen as sulphate of ammonia. The use of 150 pounds of 16 per cent superphosphate per acre increased the yield of rice 239 pounds per acre a year during the thirteen years of the experiment. The treat- ment of 150 pounds of superphosphate and 75 pounds of sul- phate of ammonia made an average yield of 2,208 pounds of rice per acre, or 408 pounds more than the yield of rice on unfertilized soil. Both of these treatments made an average profit of approximately $4.00 per acre during the period. Applications of fertilizers made after the rice was planted produced larger yields than applications made at planting time. The largest yield resulted from fertilizers applied six weeks after the rice was planted. The application of 100 pounds of sulphate of ammonia, six weeks after planting, however, made an average increase of only 98 pounds of rice per acre more than the application at planting time. This increase is not enough to justify the trouble and ex- pense involved in applying the fertilizer at a separate oper- ation. On the other hand, the application of 150 pounds of superphosphate alone and with 100 pounds of sulphate of ammonia per acre six weeks after planting made average yields of 254 and 374 pounds per acre, respectively, more than the yield resulting from the same treatments applied at planting time. These are significant and profitable in- creases and indicate that superphosphate, whether used alone or with sulphate of ammonia, should be applied about six weeks after planting. When yields and profits resulting from the use of fertiliz- ers and the convenience of applying fertilizers are consid- ered, the results reported in this Bulletin show that 100 pounds of sulphate of ammonia per acre applied at planting time is perhaps the best fertilizer practice for rice in Texas, especially in the Beaumont district. The use of (a) 50 pounds of sulphate of ammonia per acre, (b) 150 pounds of superphosphate, and (c) 300 pounds of superphosphate and 100 pounds of sulphate of potash per acre, however, made substantial profits. These results are probably applicable to similar soils in other parts of the rice-belt of Texas. CONTENTS PAGE Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A . . . 5 Soils and rainfall of the rice-growing region of Texas . . . . . . . . . . . . . 6- Soils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Rainfall . . f . . . . . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 7- Irrigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7f -_ Review of fertilizer Work on rice in the United States . . . . . , . . . . . . . 8 Object of fertilizer experiment . . . . . . . . . . . . . . . . . . . . . . . p . . . . . . . . 9‘ Method of conducting the experiment . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Size of‘ plats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Plowing the land . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10= Rate of seeding rice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 10 Time and depth of irrigation . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 10 Experimental data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Results secured with different fertilizers . . . . . . . . . . . . . . . . . . . . 11 Time of application of fertilizers . . . . . . . . . . . . . . . . . . . . . . . . . . . 131 Profits obtained from use of fertilizers . . . . . . . . . . . . . . . . . . . . . . . . . 16 Discussion of results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Summary . . . . . . . . . . . T . . . . . . . . . . . . . . . . . . ; . . . . . . . . . . . . . . . . . . 19- Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 BULLETIN NO. 398 . JUNE, 1929 FERTILIZERS FOR RICE IN TEXAS E. B. REYNOLDS AND R. H. WYCHE Rice was grown to a small extent without irrigation in Texas per- haps as early as 1863, but the crop- did not become of commercial importance until more than thirty years later. There were 335 acres of rice in Texas in 1879 and 178 acres in 1889, according to the United States Census. The growing of rice on a commercial scale in Texas really began in 1897 with the advent of irrigation, and the industry received a great impetus from the success of the rice grow- ers in southwestern Louisiana. By 1899, the acreage devoted to rice in Texas had increased to 8,711 acres, all of which was in the Beau- mont district, except 200 acres in Colorado County. The industry developed rapidly during the next decade. Texas grew 237,568 acres of rice in 1909; 164,481 acres in 1919; and 145,926 acres in 1924, according to the United States Census. The largest acreage of rice in Texas in any year was 303,000 acres, which occurred in 1913. Since then the acreage has gradually declined until in 1928 there were only 160,000 acres. In 1879, Texas had 0.2 per cent of the rice acreage in the United States; 0.1 per cent in 1889; 2.5 per cent in 1899; 38.9 per cent in 1909; 18 per cent in 1919; and about 16 per cent in 1927. The rice-growing industry in Texas first developed around Beau- mont and was undoubtedly stimulated by the success of the rice grow- ers in southwestern Louisiana. In 1899, there were 5,859 acres of rice in Jefferson County, which was 62 per cent of the riceacreage in Texas. There were 2,347 acres devoted to rice in Orange County in 1899. The industry gradually spread westward and southwest- ward. In 1919, Matagorda County grew 37,927 acres of rice, or only 5,000 acres less than Jefferson County, while in 1924 there were 61,- 599 acres of rice in Matagorda County as compared with 16,871 acres in Jefferson ‘County. Wharton County ranked second in acreage in 1924 with 23,638 acres. In 1924, the center of rice production in Texas was in Matagorda, Jackson, and Wharton Counties, according to the United States Census. While the rice-growing industry in Texas was established on a com- mercial scale in 1897, it was not until 1909 that experimental work was planned to study the problems involved in the production of rice in the State. In 1909, the Rice Experiment Station was established at Beaumont in Jefferson County. Since that time the experiment a station has made studies on some of the main problems encountered in the growing of rice, such as the testing of varieties; selection and breeding; methods of production, including time, method, and rate of seeding; irrigation; rotations; and the use of fertilizers. 6 BULLETIN NO. 398, TEXAS AGRICULTURAL EXPERIMENT STATION During the first few years of rice-growing in the State, little or no attention was given t0 the use of commercial fertilizers. It was the common practice for the farmers to grow rice on the same land year after year until the yields became unprofitable, and then they would move to new land. As the acreage of virgin, or sod, land suitable for rice decreased and the yield of rice on old land declined, many farm- ers began to use commercial fertilizers in an attempt to increase the yield of rice. At the present time it is estimated by the American Rice Growers Cooperative Associati0n* that approximately 60 per cent of the rice farmers in the Beaumont district use commercial fertilizers in some form. During the season 1925-1926, 762 tons of fertilizer were sold in Jefferson County, although the average yearly sales for the fifteen years, 1911 to 1926, were about 1,370 tons. It is not known, how- ever, how much of this fertilizer was used on rice. Superphosphate (acid phosphate) seems to be the principal fertilizer used, although some sulphate of potash was sold. This fertilizer practice has de- veloped without any experimental evidence and apparently is based entirely on the experience and opinion of farmers; but the opinion of farmers is not in general agreement as to the best fertilizer prac- tice. It is estimated that one-third of those who use fertilizer on rice regard the practice as unprofitable, although the yield of rice is increased somewhat, while others are of the opinion that the practice is profitable. In the Beaumont district, the farmers who do not use fertilizer for rice are farming the heavier soils. While small amounts of fertilizers are sold in Colorado, Jackson, Matagorda, and Wharton Counties, which comprise the western part of the rice-growing area of Texas, apparently little fertilizer is used on rice in the area. SOILS AND RAINFALL OF THE RICE-GROWING REGION OF TEXAS Rice requires a rather high temperature and an adequate and de- pendable supply of water for irrigation during the growing season. Rice grows well on many kinds of soil but usually produces larger yields on the heavier types of soil, such as silt loams and clays, with almost impervious subsoils. Subsoils of this character are a distinct advantage because they prevent excessive percolation of water down through the soil and are therefore conducive to the most eflicient use of irrigation water. The soils and climatic conditions of the humid part of the Gulf Coastal Plains of Texas are well adapted to the grow- ing of rice. The humid part of these Plains, extending from the Sabine River on the east to the San Antonio River on the west, com- prises the rice-growing region of Texas. The topography of the region is generally fiat, the elevation increasing about one foot to the mile *This information was furnished by Mr. A. H. Boyt, President, Ameri- can Rice Growers Cooperative Association, Beaumont, Texas. FERTILIZERS FOR RICE IN TEXAS 7 inland from the Gulf of Mexico. This gentle slope allows fairly ade- quate surface drainage and at the same time it is favorable to the holding of irrigation water on comparatively large areas of land by field levees. The region consists mostly of open prairies, except along the stream bottoms, which are usually heavily timbered. The follow- ing counties comprise the greater part of the rice-growing region of the State: Brazoria, Chambers, Colorado, Fort Bend, Galveston, Har- ris, Jackson, Jefferson, Liberty, Matagorda, Orange, Waller, Wharton, and Victoria. Soils The principal rice soils are the gray to brown or almost black soils underlain by heavy, almost impervious clay subsoils. These soils are classified into several different types. Lake Charles clay, which has a dark gray to black surface soil underlain by a gray almost impervious clay subsoil, is p-erhaps the most important rice soil of the region. Crowley clay has a brownish-gray to brown surface soil which is underlain by a bluish gray, sticky clay subsoil, mottled with yellow and brown. This is an important rice soil locally in the eastern part of the rice-growing area, but it is not nearly so extensive as the Lake Charles soils. While the Lake Charles soils are the more desirable soils for rice, the crop is grown to some extent on the gray soils of the Edna series. Rainfall The average yearly rainfall at several points in the rice-growing area of Texas is shown in Table 1. The data in the table were taken from the United States WeatherBureau, “Climatological Data: Texas Sec- tion,” annual summary for 1927. In this table the stations are ar- ranged in order from east to west; that is, the eastern-most station appears first in the table and the others follow as one proceeds west- ward. It will be observed that the yearly rainfall decreased gradually from east to west. For instance, the average yearly rainfall is 49.73 inches at Beaumont, in the eastern part of the area, and 36.87 inches and 35.66 inches at Edna and Victoria, respectively, in the western part of the area. This is a difference of about 14 inches in the rain- fall at Beaumont and Victoria, which are approximately 200 miles apart. Irrigation The larger streams of the area, such as the Neches, Trinity, Brazos, and Colorado Rivers, are the main sources of water used for the irri- gation of rice. Artesian water, however, is available in some sections. While there are large areas of soil suitable for the growing of rice, all of these areas are not accessible to the available sources of water. The amount of water required for irrigating rice depends upon sev- eral factors: (1) The individual user of water, (2) the nature of the soil, and (3) the amount and distribution of rainfall. More water 8 BULLETIN NO. 398, TEXAS AGRICULTURAL EXPERIMENT STATION is required in years of light rainfall than in years of heavy rainfall. In general, however, about 24 inches of water is used in an average season in the rice-growing region of Texas. Table 1.—Average yearly rainfall in inches at different places in the rice-growing area of Texas. _ Length of Place County Rainfall, record, inches years Orange . . . . . . . . . . . . . . . . . . . . . . . . . Orange . . . . . . . . . . . . . . . . . . . 42.42 20 Beaumont . . . . . . . . . . . . . . . . . . . . . . . Jefferson . . . . . . . . . . . . . . . . . 49.73 34 Liberty . . . . . . . . . . . . . . . . . . . . . . . . . Liberty . . . . . . . . . . . . . . . . . . 49.74 24 Houston . . . . . . . . . . . . . . . . . . . . . . . . Harris . . . . . . . . . . . . . . . . . . . 45.84 38 Rosenberg . . . . . . . . . . . . . . . . . . . . . . Fort Bend . . . . . . . . . . . . . . . . 42.39 13 Brazoria . . . . . . . . . . . . . . . . . . . . . . . . Brazoria . . . . . . . . . . . . . . . . . . 47.85 37 Matagorda . . . . . . . . . . . . . . . . . . . . . . Matagorda . . . . . . . . . . . . . . . 44.43 18 Danevang . . . . . . . . . . . . . . . . . . . . . . . Wharton . . . . . . . . . . . . . ._. . . 42.31 32 Edna . . . . . . . . . . . . . . . . . . . . . . . . . . . Jackson . . . . . . . . . . . . . . . . . . 36.87 19 Victoria . . . . . . . . . . . . . . . . . . . . . . . . Victoria . . . . . . . . . . . . . . . . . . 35. 66 33 REVIEW OF FERTILIZER WORK ON RICE IN THE UNITED STATES Experiments with fertilizers on rice have been conducted at the Rice Experiment Station, Crowley, Louisiana, since 1910. These ex- p-eriments have been conducted on Crowley silt loam, which is the typical rice soil of the rice-growing area in southwestern Louisiana. The results of the work published in the Twenty-eighth Annual Re- ‘port of the Louisiana Agricultural Experiment Station (1915) stated that the use of 200 pounds of acid phosphate (superphosphate) per acre produced the most profitable rice crops five years in succession. Potash salts did not produce appreciable increases in yield. It was found also that readily available forms of nitrogen were better than organic forms of nitrogen for Honduras rice, but there was not much difference in the two forms of nitrogen for the late-maturing varieties. The Twenty-ninth Annual Report of the Louisiana Agricultural Experiment Station (1916) stated: “It is believed that suflicient data have been gathered during the past seven years to warrant dis- continuing experiments which involvethe continuous use of commer- cial fertilizers in an attempt to force land to grow rice year after year Without rest or crop rotation.” Later, it was reported in the Thirty-fifth Annual Report of the Louisiana Agricultural Experiment Station (1923) that the fertilizer experiments at Crowley had shown that no commercial fertilizer could be relied upon t0 sufficiently increase or maintain the yield of rice on land similar to the soil, the Crowley silt loam, on the Rice Experi- ment Station at Crowley. The results of the fertilizer work at the Rice Experiment Station, Crowley, Louisiana, from 1919 to 1923, inclusive, were published in United States Department of Agriculture Bulletin 1356 (1925). Superphosphate (acid phosphate), sulphate of ammonia, nitrate of FERTILIZERS FOR RICE IN TEXAS 9 ‘soda, cottonseed meal, dried blood, sulphate of potash, manure, and lime were used. During the five years dried blood, manure, and sul- phate of potash were the only fertilizer treatments that- produced larger yields than unfertilized soil, but the yield of rice Was not in- creased enough to pay the cost of the fertilizers. It was concluded from these results that commercial fertilizers were not profitable un- Ider the conditions at Crowley. The practice of growing soybeans and plowing under the soybean plants after harvesting the beans and planting rice on the land the following year gave an increase in yield ~of 915 pounds of rice per acre, or 63.6 per cent over the yield of rice -on unfertilized land. The United States Department of Agriculture has conducted ex- periments with fertilizers on rice at the Biggs Rice Field Station, Biggs, in the Sacramento Valley of California. The results of the ‘work were published in Bulletin 1155 of the United States Department -of Agriculture (1923). The work was done on Stockton clay adobe soil, which is reported as being representative of a large part of the rice-growing area of California. Applications of 350 pounds of super- phosphate, 100 pounds of sulphate of ammonia, and 100 pounds of sulphate of potash per acre were applied alone and in all combinations. Nitrate of soda, cottonseed meal, dried blood, lime, and manure were ;also included in the experiment. During the three years 1914, 1915, sand 1916, the application of one ton of manure per acre produced the largest average yield, 4,488 pounds per acre, or 879 pounds more than the yield of the untreated check plats. Sulphate of ammonia made the “second highest yield, 4,260 pounds per acre, which was an increase of "651 pounds per acre over the yield of the check plats. Dried blood and cottonseed meal increased the yield 646 and 583 pounds per acre, respectively. The use of superphosphate and sulphate of ammonia to- _-gether increased the yield 364 pounds per acre. The California Agricultural Experiment Station in Bulletin 454 (1928) reports the results of experiments with sulphate of ammonia as a fertilizer for rice. In 1925 and 1926, the application of 100 pounds of sulphate of ammonia made an average increase of 645 pounds -of rice per acre more than the untreated plats. In 1927, the applica- tion of 150 pounds of sulphate of ammonia per acre produced an in- crease of 1,198 pounds of rice per acre over the yield of the unfertil- zized plats. OBJECT OF THE FERTILIZER EXPERIMENT As mentioned in the introduction, experiments were begun to study ‘the use of fertilizers on rice soon after the Rice Experiment Station was established. The main objects of these experiments were to de- "termine (1) the best kind and amounts of fertilizer to use, and (2) the optimum time (stage of growth of rice) to apply fertilizers to rice. The purpose of this Bulletin is to report the results obtained in con- ducting these experiments from 1915 to 1928, inclusive. 1O BULLETIN NO. 398, TEXAS AGRICULTURAL EXPERIMENT STATION METHOD OF CONDUCTING THE EXPERIMENT The fertilizer work at Beaumont has been done on Crowley clay and Lake Charles clay soils. The Lake Charles clay is the most important soil for rice in Texas, While the Crowley soils, especially the Crowley silt loam, are the main rice soils in southwestern Louisiana. These soils are rather difficult to Work, but if they are managed properly a good seed-bed- can usually be obtained. The Lake Charles and Crow- ley soils are naturally productive and are well adapted to the grow- ing of rice. Size 0f Plats The size of plats has varied somewhat during the course of the ex- periment. In the earlier years of the work the plats were one-tenth acre in size and usually the treatments were not replicated. Since 1921_, the plats have been 1/33 to 1/22 acre in size and each fertilizer treatment l1as been replicated two or more times in the test each year. Each plat was surrounded by a levee. This served the purpose of watering each plat to the same depth and prevented the fertilizer treat- ment on a plat from influencing the yield on adjacent plats. Plowing the Land Usually the land in the fertilizer work was plowed in the late fall after the rice was harvested, but sometimes it was not possible to plow the land at that time on account of rainy weather. If the plowed land became foul with weeds, it was disked thoroughly to kill the weeds. A good seed-bed was prepared by disking and harrowing previous to planting the rice. While the preparation of the seed-bed was not uni- form during the 13 years of the experiment, it was the same for all plats each year. Rate of Seeding Rice The rate of seeding the rice in the experiment has varied somewhat but 1n any year the rate of seeding was the same for all plats in the experiment. In most cases the rate of seeding has been 95 pounds per acre. Blue Rose, a late-maturing variety, was used in the fer- tilizer work in 1916, 1917, 1918, 1922, 1923, and 1927. Texas For- tuna, a medium late-maturing variety, was grown for six years. Early Prolific, an early variety, was used in the experiment in 1921. Time and Depth of Irrigation The first irrigation was given two to four weeks after the rice had emerged, the time depending upon the amount of rainfall. Usually a four-inch irrigation was given about four weeks after the rice came up to a good stand. No additional water was applied until the water had diminished to about an inch deep on the plats. Then the water was turned on to a depth of 3 to 4 inches and gradually increased at each succes- FERTILIZERS FOR. RICE IN TEXAS l1 sive irrigation until a depth of 6 inches was obtained at the end of the season. The water was not drained off the field until the heads of the rice_had turned down, at which time it was drained off to per- mit the land to dry for harvesting. EXPERIMENTAL DATA The studies on fertilizers for rice consisted of two distinct phases: (a) experiments in which different fertilizers were used to determine the best kinds and amounts of fertilizers, and (b) experiments 1n which the fertilizers were applied at different dates to determine the optimum time (stage of growth of rice) of applying fertilizers. The former were conducted during the Whole period of the experiment from 1915 to 1928, inclusive, while the latter have been conducted since 1.922. Results Secured with Dilferent Fertilizers The results of experiments with different fertilizers are given in Table 2. During the earlier years of the experiment the fertilizers were applied when the rice was planted. Since 1924, however, the fer- tilizers have been applied about six weeks after planting. The appli- cation of 100 pounds of sulphate of ammonia per acre made the larg- est average yield during the thirteen years of the experiment, during the six years 1915 to 1921, and during the eight-year period, 1915 to 1923. This treatment made an average yield of 2,353 pounds of rough rice per acre during the thirteen years, which was 553 pounds, or 30.7 per cent more than the yield of rice on unfertlized land. The treat- ment also increased the yield of rice 38.5 per cent and 41.6 per cent during the eight years and six years, respectively. As will be shown later, the treatment of 100 pounds of sulphate of ammonia was the most profitable treatment used. The treatment consisting of 300 pounds of superphosphate and 200 pounds of sulphate of ammonia per acre produced the second largest average yield for the thirteen years, for the eight years, and for the SIX years. ~ The application of 150 pounds of superphosphate and 100 pounds of sulphate of ammonia made the third highest yield of rice in the thir-v teen-year average, in the eight-year average, and in the six-year average. An application of 6 tons of manure per acre was included in the ex- periment from 1915 to 1921, inclusive. During this period it was the only treatment that did not produce a larger average yield than land which received no fertilizer, and for this reason the treatment was discontinued. Cottonseed meal did not give as good results as sulphate of ammonia, although it made considerably larger average yields than manure. In 1924, the fertilizer work was expanded to include several rates of application of sulphate of ammonia and of superphosphate to deter- mine the effect of larger amounts of these materials on the yields of .82 Ea £2 E @2625 3? .-~ . . . . ‘.., . . . . . . .... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .... . . .. . .. . . . . . . . . I ..... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . diozbbw Lo 3233M ooN dwwnawonnpoanm com 12 BULLETIN NO. 398, TEXAS AGRICULTURAL EXPERIMENT STATION ..-....... . . . . . . . . . . . . . . . . .... . . . . ..QMNZQWOH~Q.~QQU@ dhncwg 802 . . . . 2N2 ............................wmwmwwm omwmmwm aomfimwwfi . . . . . . . . . . . ..3:cm2 ooofi . . . . . . . . .. ....... . .. $2 $8 .... .... .... . . .. .... $2 min mwom i“: owmm o2: 82 if . . . . .;.:_E%¢=E@@=m a2 Amog voownofioU 00m . . . . . . $8 92m ..:§2 mmfimpvmmfiwfi @2252 3M3 $2 .....__8E.83¢o:¢u 8m mwom 2mm mfim 82.. mhmm 2&2 $2 82 £2 $2 8S mm? mmwm SRN 8: 32 22m . . . . . éflimfiigsg=w 8m dEoEEm Ho 32316 00m S8 8mm 3mm 8mm Rmm $3 8mm M52 .22 $2 $8 $3M $3 oowm S2 82 $2 . . . . . zfiwnnw¢éw=vg=w o2 .NMGOEE.Q Lo ofiwnfisw cow mwom omom . wwom 92m mmom Q2 22m $2 £8 ail MSN 3% 58 $2.. 2.2 9M2 mmfi . . . . . Azwngwofirvnsw m» dLcoEEm mo ogmsficw cm. .................... . . . . . . . . . . ..QHQSQwOSQMOQUW 28m mmom 08m 2am $5 2.2 8mm $2 M68 Sm 98m 5a wag 8% 23 £2 $2 . . . . . afifimanghvgfi o2 .................... . . . . . . . . . . ..QMGSQwOSQuQQUW m2~ mmmm flaw 32.. Qfi m2; ENN 2K2 XKN $3 2% a?» owmm 2§ 88 Q3 22 rficofiiw Ho $522215 o2 --........-....-.-..-......-..%%$§@@Ami%%@x@@@@#@@§@........'¥w...v_q-..-..-...-..-....N@GQEEN%OUQN§Q@:@ 22 8M2 E2 mt; MR2 m2: C: 22 22 9M2 $3 23 g3 mmom $2 $2 Sm . . . . . . . Jaoiumvb oZ .34 a3 2S _ .23 .25 .23 .25 .23 .23 .23 .23 .23 .23 £5 .25 .23 £3 wfizéfl: @2222 .2222 32-22 96a ibwoh 6.69» £39» 62min wining “on Qzm =8Enh Emmm in £2 S2 £2 22 2&2 82 22 S2 82 22 22 22 22 .23 h... uwm~o>< uflvgmwuvfi .22 3 22 62208235 honmmpom “E0283. Bob M3282 out Lo 0.8a 3n nufimruld Baa? FERTILIZERS FOR RICE IN TEXAS _ 13 rice. The use of potash alone and in combination with sulphate of ammonia and superphosphate was included also. The average yields of rice obtained from the several fertilizer treatments during the five years, 1924 to 1928, inclusive, are given in the last column of Table 2. The yield of rice increased as the amount of sulphate of ammonia was increased, but the increase in yield was not directly proportional to the amount of sulphate of ammonia applied. Superphosphate was applied at the rate of 150 pounds per acre dur- ing the period of the experiment and at the rates of 75, 150, and 300 pounds per acre during the last five years, 1924 to 1928. The appli- cation of 150 pounds per acre made the largest average yield, 2,054 pounds per acre, or 206 pounds more than the yield of untreated soil during the five years. The combination of 300 pounds of superphosphate and 200 pounds of sulphate of ammonia did not produce as large an average yield as the application of 200 pounds of sulphate of ammonia. During the last five years, 1924 to 1928, inclusive, the largest aver- age yield, 2,437 pounds of rough rice per acre, resulted from the use of a complete fertilizer consisting of 300 pounds of superphosphate, 200 pounds of sulphate of ammonia, and 100 pounds of sulphate of potash per acre. This treatment made an increase of 589 pounds, or 31.8 per cent, over the yield of the soil which received no fertilizer treatment. The increase in yield, however, was not profitable, as will be shown later (Table <1), Potash when used alone did not increase the yield of rice, but when 1t was ap-plied along with superphosphate increase in yield resulted. During the thirteen years of the experiment, the application of sul- phate of ammonia at the rate of 100 pounds per acre made an aver- age increase of 553 pounds of rice per acre, which was an increase of about 27 pounds of rice for each pound of nitrogen applied. (One hun_- drcd pounds of sulphate of ammonia contains 20 pounds of nitrogen.) For the last five years, however, the average increase was only 17 pounds of rice per acre for each pound of nitrogen applied. The results given in Table 2 show that the soil responded to both nitrogen and phosphoric acid, but nitrogen gave larger increases in yield than phosphoric acid, indicating that nitrogen is needed more than phosphoric acid for the production of rice. The application of 100 pounds of sulphate of ammonia per acre was the best treatment used when both yield and profit are considered. Time of Application of Fertilizers Observations made during the course of the experiments reported in Table 2seemed to indicate that the application of fertilizers, especially phosphoric acid, at planting time was beneficial to weeds at the ex- pense of the rice crop. It was noted that the growth of weeds was more abundant on plats which received fertilizer than it was on un- 14 BULLETIN NO. 398, TEXAS AGRICULTURAL EXPERIMENT STATION fertilized land. In 1917, it- was observed that the weed growth was greatest on the plats which received the largest amounts of fertilizers and that the yields of rice apparently decreased as the rate of fertilizer increased, due to the excessive growth of weeds. Subsequent Work in other parts of the World has shown that applications of fertilizers after the rice has been planted give larger yields than applications of fertilizers at planting time. The Louisiana Agricultural Experiment Station (Thirty-fifth An- nual Report, 1915), in reporting the results of fertilizer work which included phosphoric acid, stated: “A serious difficulty, however, to be contended in continuous cropping is that the application of acid phosphate accelerates the growth of grasses and weeds until these field pests become a menace to the crop.” In fertilizer experiments with rice in the Dutch East Indies (Ex- periment Station Record él5z622), multiple or fractional applications of superphosphate and of sulphate of ammonia were more profitable than the same amount app-lied at one application. The United States Department of Agriculture carried on some work with rice in California in which fertilizer was applied (a) when the rice plants were 3 inches high, (b) when the first heads were appear- ing, and (c) two weeks after first heading. The results of this work were published in United States Department of Agriculture Bulletin 1155. The application of fertilizer when the plants were 3 inches high produced considerably larger yields than later applications. As an average of the three years, 1917, 191.8, and 1919, fertilizer applied when the plants were 3 inches high produced 226 pounds of rice per acre more than the fertilizer applied when the first heads appeared, and 1124 pounds per acre more than the fertilizer applied two weeks after first heading. 11; seemed desirable, therefore, to conduct experiments to determine the optimum time of applying fertilizers to rice under conditions pre- vailing in Texas. Accordingly, an experiment was outlined in 1922 with the view of obtaining the desired information. Previous work (Table 2) had shown that 100 pounds of sulphate of ammonia per acre was one of the best fertilizer treatments used. This treatment and 150 p-ounds of superphosphate were used alone and in combination in the work on time of application of fertilizers. In 1922, these treatments were made at planting time and 12 weeks after planting. Since 1922, the fertilizers have been applied when the rice was planted, 6 weeks after planting, 12 weeks after planting, and in fractional applications in which one-third of the fertilizer was applied at planting time, one-third 6 weeks after planting, and one- third 12 weeks after planting. The results obtained in conducting the work involving dates of ap- plication of fertilizers are given in Table 3. During the six years, 1923 to 1928, inclusive, the application of fertilizers 6 weeks after FERTILIZERS FOR RICE IN TEXAS 15 planting made larger yields than applications made at other dates. There was not, however, very much difference in the yields of rice re- sulting from the four dates of application of 100 pounds of sulphate of ammonia. The application of superphosphate 6 Weeks after planting made an average yield of 254 pounds more per acre than the application made at planting time. The- treatment of 100 pounds of sulphate of am- monia and 150 pounds of superphosphateapplied six Weeks after plant- ing made an average yield of 3'74 pounds of rice per acre more than the treatment applied at planting time. These increases in yield are suffi- cient to justify the expense of applying the superphosphate at a sepa- rate operation and indicate that if phosphoric acid is used alone or with sulphate of ammonia, it should be applied about 6 Weeks after planting. Table 3.—-Yield per acre of rice fertilized at different dates. 100 lbs. sulphate _ _ 100 lbs. sulphate 150 lbs. of ammonia, Year Time of applying None of ammonia superphosphate 150 lbs. superphosphate Lbs. Lbs. Lbs. Lbs. 1922 When rice was planted 2159 2615 2089 2093 12 weeks after planting 2544 2026 2343 When rice was planted 1307 1459 1416 1350 6 weeks after planting 1742 2134 1830 1923 12 weeks after planting 1982 1634 1830 Fractional application* 1307 1437 1307 When rice was planted 2420 2741 2554 2526 6 weeks after planting 3042 2741 2253 1924 12 weeks after planting 2528 2446 2775 Fractional application* 2866 2610 2627 When rice was planted 1379 1639 1144 1205 6 weeks after planting 1774 1329 1865 1925 12 weeks after planting 1425 1287 1474 Fractional application* 1529 1221 1089 When rice was planted 1963 2602 2222 2092 6 weeks after planting 2274 2200 2390 1926 12 weeks after planting 2360 2257 1867 Fractional application* 2297 2223 2332 When rice was planted 1821 1893 1501 1729 6 weeks after planting 2112 1984 1977 1927 12 weeks after planting 2123 1803 2033 Fractional application* 2053 1591 1785 When rice was planted 2103 2371 2178 1956 6 weeks after planting 2352 2151 I 2789 1928 12 weeks after planting 2712 2437 2690 Fractional application* 2789 2365 2657 Av. 1922 When rice was planted 1879 2189 1872 1850 to 1928 12 weeks after planting ' 2239 1984 2145 Av. When rice was planted 1832 211s i 1836 1810 1923 6 weeks after planting 2216 2090 2184 to 12 weeks after lanting 2188 1977 2112 1928 Fractional app ication* 2140 1908 1966 *One-third of fertilizer applied a_t planting time, one-third six weeks after planting, and one-third twelve weeks after planting. 16 BULLETIN NO. 398, TEXAS AGRICULTURAL EXPERIMENT STATION Fractional application of the fertilizer made larger average yields than application made at planting time. When the three treatments are considered together, the fractional application made an average yield of 2,005 pounds of rough rice per acre, or only 84 pounds more per acre than the application made at planting. This small increase probably Would not justify the expense involved in making the frac- tional applications. . The results on time of ap-plication of fertilizers show that if sul- phate of ammonia is used alone, it should be applied when the rice is planted, since the increase in yield from later applications probably would not justify the additional expense of applying the fertilizer at a separate operation. If superphosphate is used alone or in combina- ~ tion with sulphate of ammonia, probably it should be applied about six weeks after planting the rice because the increase in yield ‘obtained by applying the treatment at that time Was large enough to offset the expense of applying the fertilizer at a separate operation and still leave a substantial profit. Where fertilizers containing sulphate of am-e monia are applied after planting, care should be taken to make the application when the plants are dry, because the sulphate of ammonia may burn the plants if applied when they are wet. PROFITS OBTAINED FROM THE USE OF FERTILIZERS The best fertilizer to use on rice or any other crop is the one that will give the largest profit over a period of years. The fertilizers that produce the largest increases in yield are not always the most profit- able. The yields of rice produced by the various fertilizer treatments have been discussed (Table 2), but the yields alone do not necessarily reveal the most suitable or most profitable treatment to use in farm practice. When the cost of the fertilizers and the prices of rice are known, however, one can readily determine the most profitable treat- ment. The profits and losses resulting from the use of fertilizers on rice at the Experiment Station, Beaumont, Texas, are given in Table 4. The profits and losses were obtained by deducting the cost of fertilizers from the value of the increase produced by the fertilizers and do not take into consideration the expense involved in applying the fertilizer and harvesting and threshing the increase produced by the fertilizers. The wholesale price of rice ranged from $2.17 to $2.78 per 100 pounds during the last five years and the average price was $2.46 per 100 pounds, but for the purpose of calculating the profits here the price of $2.45 was used. The average retail prices of fertilizer materials per ton used during the five years, 1924 to 1928, were: sulphate of am— monia, $77.40; superphosphate (16 per cent), $22.35; and muriate of potash, $53.35. Sulphate of potash was used in the work but since it is not readily obtainable onthe market and retail prices are not at i.» - rtwzimmaumsiwilwu! . ~. . 17 FERTILIZERS FOR RICE IN TEXAS .32 m mofixxwaw “lo mm? admin can.» wfizc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............-.....§MG%OQ %Q QHNQQ<5Z . opwnnwosakoasm oom mEoEEw oo wfiwafinw oom R.@ fi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .....-.........H~M.N.HOQ %Q Qwflgmmnww i owmnnmoaako 2m oom 3 m.‘ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .SmNHOQ MO UQNQQaH-w NMQOEEN mo oflwafinm ooN ahu@.§l|- .-...-.-. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-.. .--.§WNP°Q %o $2m| o3: in mmm 2: 3: 3.2 w? . . . . . . . . ¢ ................womnn8nahva=m oom .NMQOEEN mo ufiwnflsw oom 3N 3m £1. Em S; 3m Q92 w? . . . . . . ................B§Ew¢n@$@=m o2 . £50528 Mo womnfinw oofi . . . . . . . ....... . . . - . . . . .-.UPN§QMQ£QHQQU.Z dMcoEEm mo ofiwnfism om *@¢-ml . . . . . . ... . .. ......-.. .- . . . . . . .. .. . . . . . . . . . . . . . . . . . . . ..............Qfi.flggwoggh@gg@ 3.», E; 3m oom m: Q 2.. _ 3m omm . . . . . . . . . . . . . . . . . . . . . . . . aafiawoamsg=w S; @§.§ .. - .. -......- . . . . . . . . . . . . . . . ... .... . . . . . . . . . . . . . ......QH.N§QWQ§QHUQHM@ mhé owfl moo owm . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . CimdgoaammowgangHam oom mmQ 3m Qiw mam £5 w 8.» w .32 fi m3 . . . . . . . . . . . . . . . . . . . .wEoEEm m. 822$ 2: . moé o fi. . . . . . . . . .. . . .. . . . . . . . . . . . . . . . . . . . .. mm m a h m o wrmq .34 GMGOEEQ o0 “Swami-m on a5 o2 Bfimifi an: oow gwfizfifi imam .62 uonsfiuow ha mwdw ow 3% 5mm ooZ uonzfiuv.“ 5Q wig“ 3 o3. mo QwoU on vflw»? E2» E Ho $00 an 213w Eur» E @2355 owmohofi whom 5Q @353 Jqucbwuffi wflw¢3..@_ .28» m 2: 8m $2-22 diam.» 2 23 hob QGKQP Jcofismum MN fivnmiuow m0 vwfl 80km UUGMNHBO HCOMQ USN QQOQ hQQ Gui m0 Gm QmGQhUCM-IJ» MJQNP I8 BULLETIN NO. i398, TEXAS AGRICULTURAL EXPERIMENT STATION hand, the price of muriate of potash, which may be bought on most mar- kets, was used in calculating the profits from the use of potash. The treatment of 100 pounds of sulphate of ammonia per acre made an average increase in yield of 553 pounds of rough rice per acre dur- ing the thirteen years of the experiment and 345 pounds per acre for the last five years. The profit to be derived from such increase in yield Would, of course, depend upon the prices received for the rice and prices paid for the fertilizer, but on the basis of the figures given in the preceding paragraph, the treatment made an average annual. profit of $9.65 per acre for the thirteen years and $4.55 per acre dur- ing the last five years. This was the most profitable treatment used in both periods of years. During the thirteen years of the experiment, the treatments of (a) 150 pounds of superphosphate, (b) 50 pounds of sulphate of ammonia and 75 pounds of superphosphate, and (c) 100 pounds of sulphate of ammonia and 150 pounds of superphosphate were almost equally profit- able, each making an average profit of slightly more- than four dollars per acre a year. While the treatment of 200 pounds of sulphate of ammonia and 300 pounds of superphosphate made an average increase of 498 pounds of rice pe-r acre, it made an average profit of only $1.00 per acre ayear. Considering now the results for the five years, 1924 to 1928, in- clusive, it will be observed that the application of 100 pounds of sul- phate of ammonia per acre made the largest average profit, $4.55 per acre (Table 4). The treatment consisting of 3'00 pounds of super- phosphate and 100 pounds of sulphate of potash made the second larg- est increase in yield, 409 pounds per acre, and the second greatest profit, $3.97 per acre a year. The treatment of 50 pounds of sulphate of ammonia and the treat- ment of 150 pounds of superphosphate made about the same average increases in yield, 211 and 206 pounds of rice per acre, respectively, and practically the same average profit, $3.22 and $3.35 per acre an- nually. The complete fertilizer consisting of 200 pounds of sulphate of am- monia, 300 pounds of superphosphate, and 100 pounds of sulphate of potash, produced the largest average increase, 589 pounds of rice per acre, which, however, resulted in an average profit of only $0.58 per acre a year. The treatment was used at a considerable loss two of the five years, but the profit during the other three years was sufficient to offset this loss. Four treatments: (1) 300 pounds of superphosphate, (2) 200 pounds of sulphate of ammonia and 300 pounds of superphosphate, (3) 100 pounds of sulphate of potash, and (4) 200 pounds of sulphate of am- monia and 100 pounds of sulphate of potash were unprofitable, the losses ranging from $2.65 to $7.44 per acre a year for the five years. The results in Table 4 show rather conclusively that sulphate of FERTILIZERS FOR RICE IN TEXAS 19 ammonia was the most profitable treatment used in the experiment. The use of (l) 300 pounds of superphosphate and 100 p-ounds of sul- phate of potash, (2) 150 pounds of superphosphate, and (3) 50 pounds of sulphate of ammonia, however, made substantial profits. DISCUSSION OF RESULTS Sulphate of ammonia was a better source of nitrogen than cotton- seed meal or manure in the experiments at Beaumont, Texas. The use of 100 pounds per acre of sulphate of ammonia was the most profitable treatment used in the experiment. These results are in general agree- ment with the results of fertilizer experiments on rice in other parts of the world. For example, in experiments conducted at Biggs, Cali- fornia, by the United States Department of Agriculture, sulphate of ammonia was one of the most profitable fertilizers used. The Cali- fornia Agricultural Experiment Station also obtained excellent results with sulphate of ammonia. Similar results were obtained in experi- ments conducted in Guam, Hawaii, and India. In work on the time of application of fertilizers, applications made after the rice was planted gave- larger average yields than applications made at planting time. The largest yield resulted from fertilizers ap- plied SIX weeks after the rice was planted. These results are in accord with the results of somewhat similar work done in California by the United States Department of Agriculture, in which fertilizer applied when the rice was three inches high produced larger yields than fer- tilizer applied at later stages of growth. Fractional applications of fertilizers i11 which one-third of the fer- tilizer was applied when the rice was planted, one-third 6 weeks after planting, and the remaining one-third 12 weeks after planting made larger yields than single applications made at planting time. The frac- tional application of fertilizer, however, made smaller average yields of rice than single applications made 6 weeks and 12 weeks after plant- ing. Somewhat similar results have been reported from the Dutch East Indies (Experiment Station Record 45 z622). SUMMARY Applications of sulphate of ammonia made larger increases in yield than superphosphate. Treatments consisting of sulphate of ammonia and superphosphate did not produce larger yields than treatments of sulphate of ammonia alone, indicating that the soils are more deficient 1n nitrogen than phosphoric acid for the production of rice. Sulphate of ammonia was used alone at the rates of 50, 100, and 200 pounds per acre. The yield of rice increased as the rate of sul- phate of ammonia. was increased, but the yield was not proportional to the increase in the rate of sulphate of ammonia. Sulphate of am- monia applied at the rate of 100 pounds per acre produced an average increase of 553 pounds of rice per acre over the check plats and was 2O BULLETIN NO. 398, TEXAS AGRICULTURAL EXPERIMENT STATION the most profitable treatment, returning an average profit of $9.65 pert During the last five years of the experiment? this treatment produced an average increase of only 345 pounds of _. acre for thirteen years. rice per acre, resulting in a profit of $4.55 per acre. Superphosphate applied at the rate of 150 p-ounds per acre made f larger increases in yield of rice than applications of '75 pounds and Q The 150-pound rate produced an average in-, crease of 239 pounds of rice, or 14.3 per cent, over the yield of rice"; This treatment Was more profitable than the other treatments of superphosphate and gave a yearly profit of $4.16 3U0 pounds per acre. on the unfertilized soil. per acre for the thirteen years. The use of potash alone did not increase the yield of rice, but when»; used With superphosphate or With sulphate of ammonia and supcrphos- f phate it produced significant increases in yield. During the five ‘years; 1924 to 1928, the combination of 300 pounds of superphosphate and 100 pounds of sulphate of potash per acre made the second largest profit, g $3.97 per acre annually. In the Work on time of application of fertilizers, applications made}; six weeks ‘after planting the rice gave larger average yields than fer- 1.9;; tilizers applied at planting time, 12 Weeks after planting, or fractional’? applications in Which one-third of the fertilizer was applied at plant- ing time, one-third 6 Weeks after planting, and one-third 12 Weeks 5j While the application of fertilizers after planting made larger yields than applications made at planting time, the increase in. yield in the case of sulphate of ammonia probably Would "not justify the ‘T- additional expense of applying the fertilizers at a separate operation. Where superphosphate was used alone or with sulphate of ammonia,f;~' the increase resulting from applications made six weeks after planting after planting. Were large enough to be profitable. a ACKNOWLEDGMENTS Mr. A. H. Leidigh and Mr. H. H. Laude instituted and conducted i the Work from 1915 to 1920, the former remaining in charge of the H. Prince conducted the field work from project until 1925. Mr. A. 1919 to 1923, inclusive. y: ihzfifkéu ma...‘ 1.; _ _ “ hwmiswi-fi.maanima.snaci-