SUDANGRASS 
 
 IN 
 CALIFORNIA 
 
 M. L. PETERSON 
 MILTON D. MILLER 
 
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 Circular 165 
 May 1950 
 
 California Agricultural Extension 
 Service • College of Agriculture 
 University of California, Berkeley 
 
Sudangrass 
 
 is California's most productive summer-grow- 
 ing pasture crop. Its importance as a feed 
 may be expected to increase with the state's 
 expanding livestock industry. 
 
 California also produces a major portion 
 of the sudangrass seed crop. About 35 per 
 cent of all sudangrass seed grown in the 
 country in 1949 was produced in California. 
 
 New varieties are being developed that 
 show promise of increased yield. 
 
 This Circular 
 
 lists and describes the new varieties of sudan- 
 grass, and gives cultural directions for suc- 
 cessful production of the crop. 
 
 Sudangrass does best in fertile soils, where 
 warm weather and a long growing season 
 prevail. It is easily damaged or killed by light 
 frosts, and even small amounts of alkali in the 
 soil will tend to reduce yields. 
 
 The danger of stock poisoning by prussic 
 acid in sudangrass is a relatively minor factor 
 in California but certain precautions against 
 trouble are listed. 
 
 Sudangrass has been used successfully to 
 combat the effects of bloat, brought on by 
 leguminous feeds. 
 
 The Authors: 
 
 M. L. Peterson is Assistant Professor of 
 Agronomy and Assistant Agronomist in the 
 Experiment Station, Davis. 
 
 Milton D. Miller is a Farm Advisor in Glenn 
 County. 
 
 Photo on cover shows dairy cattle grazing on 
 sudangrass pasture. For maximum results, stock 
 should be removed, and the pasture allowed to 
 grow, after it has been grazed to height shown. 
 In photo at left, draft horses enjoy sudan pasture 
 at Davis. 
 
SUDANGRASS 
 
 in California 
 
 A word about the 
 possibilities • . • 
 
 About 150,000 acres of sudangrass are 
 grown in California each year, under ir- 
 rigation and on dry-land. It is the state's 
 most productive pasture crop. Yields on 
 good soil, under irrigation, at Davis, have 
 ranged between 7 and 10 tons per acre 
 on the hay-weight basis. 
 
 As a seed crop, California production 
 has ranged between 2.4 and 10.8 million 
 pounds annually during the past 20 years. 
 Seed yields average about 800 pounds 
 per acre, compared with about 370 
 pounds per acre for the entire United 
 States. Under irrigation, seed yields of 
 2,500 pounds per acre are not unusual. 
 
 As with other crops, high yields re- 
 quire good management, but with good 
 management, sudangrass seed can be a 
 profitable cash crop in California. 
 
 Some bacicground 
 information. 
 
 Sudangrass was introduced into the 
 United States as a result of systematic 
 search for a form of Johnsongrass with- 
 out rootstocks. Johnsongrass is a peren- 
 nial which develops vigorous rootstocks, 
 from which an individual plant may 
 rapidly spread and become troublesome. 
 Under cultivation, sudangrass is an an- 
 nual (dies at the end of the growing 
 season) and only under frost-free condi- 
 tions have individual plants lived over 
 winter. Sudan does not develop root- 
 stocks that live from one year to the next, 
 and is never difficult to eradicate. 
 
 Thinly spaced plants may produce 20 
 to 100 shoots from the base, while close- 
 drilled or broadcast seed shows much 
 
 less stooling (branching out from the 
 base). 
 
 The new varieties 
 are promising. 
 
 Until recent years much of the sudan 
 seed in commercial trade in the United 
 States was sold simply as sudan seed, 
 because improved varieties had not been 
 developed. An exception to this was Su- 
 dan 23, developed by the University of 
 California Experiment Station a number 
 of years ago. Recently, several new varie- 
 ties have come into production and have 
 been tested at the Experiment Station. 
 
 Sudan 23 was developed by L. G. 
 Goar, of the California Experiment Sta- 
 tion, by selection from common sudan. 
 First increase was made in 1936. Sudan 
 23 is the highest yielding variety among 
 those tested at Davis, ranging from 10 
 to 20 per cent greater than common or 
 sweet sudan. It is also a little later in 
 heading and more uniform in growth 
 characteristics than common sudan. 
 
 A particularly desirable characteristic 
 for pasture use is its ability to recover 
 quickly after grazing; production during 
 late summer and fall has ranged from 35 
 to 100 per cent greater than sweet sudan. 
 
 Sudan 23 is certified by the California 
 Crop Improvement Association. About 
 3.5 million pounds of seed of this variety 
 were produced in the state during 1949. 
 
 Sweet sudan is easily identified by 
 its broad, dark green leaves and thick, 
 juicy stems which often show a whitish 
 "bloom." The midrib of sweet sudan 
 leaves is cloudy or milky colored, while 
 those of other varieties are clear. The 
 stalk is sweeter and jucier than common 
 sudan, is less likely to shatter its seed. 
 
 [3] 
 
and is more resistant to foliage diseases 
 in humid areas where such diseases are 
 a problem. The hulls which surround the 
 seeds are dull brick red. 
 
 Sweet Sudan was developed by Dr. R. 
 E. Karper and Dr. J. R. Quinby of the 
 Texas Agricultural Experiment Station, 
 from a cross between Leoti, a sweet sor- 
 ghum, and common sudan. The sweet, 
 juicy stalk and non-shattering seed habit 
 and some other desirable characteristics 
 come from the Leoti parent. 
 
 Yields of sweet sudan at Davis have 
 been about equal to common sudan, but 
 below sudan 23. These differences are due 
 largely to the slower recovery after cut- 
 ting. 
 
 Seed yields of sweet sudan are greater 
 than those of sudan 23, and in recent 
 years sweet sudan has been the most 
 widely-grown variety, for seed produc- 
 tion, in the state. 
 
 Tift Sudan is highly resistant to the 
 leaf diseases found in the warm, humid 
 regions of southeastern United States, 
 and it is thought that demand for seed 
 for export to these regions could increase. 
 
 Leaves of tift sudan are broad, like 
 those of sweet sudan, and dark green in 
 color. The seeds range in color from dark 
 mahogany to yellow or straw color. 
 
 The variety was developed by Dr. 
 Glenn W. Burton, at the Georgia Coastal 
 Plain Experiment Station, Tifton, Geor- 
 gia. Like sweet sudan, it is a cross be- 
 tween Leoti and common sudan, but the 
 sweet, juicy stem characteristics were not 
 retained, even though various other 
 growth characteristics are common to the 
 two varieties. 
 
 Because forage yields of tift sudan have 
 been relatively low, and diseases rarely 
 occur in the arid regions of California, 
 tift is not recommended for pasture hay 
 in the state. But since seed production in 
 the area where tift is adapted is uncertain, 
 if not impossible (due to high humidity 
 and contamination with Johnsongrass) 
 seed production for export, as stated, 
 might be worthwhile. 
 
 A seed yield of 1,445 pounds per acre 
 was obtained at Davis, under irrigation. 
 
 Other varieties. Common sudan in- 
 cludes imported seed and the increase of 
 seed from previous importations. As 
 might be expected, it is quite variable. 
 
 Common sudan heads earlier than the 
 imported varieties. 
 
 Trials have indicated that imported 
 sudan was similar in growth characteris- 
 tics, yield, and disease resistance to the 
 common, domestic-grown seed. 
 
 Experimentation 
 is being continued. 
 
 Sudangrass breeding is in progress at 
 several of the state experiment stations, 
 and one of the objectives of plant breed- 
 ers is to develop varieties containing low 
 concentrations of prussic acid (see page 
 6). Variations are known to occur, and 
 strains may be available eventually that 
 are less likely to cause poisoning of stock, 
 than those in common use today. 
 
 The following table shows the yields 
 of various sudangrasses in tons of hay 
 per acre (figured at 12 per cent mois- 
 ture) grown at Davis in 4 different years. 
 
 Variety 
 
 1944* 
 
 1945 
 
 1948 
 
 1949 
 
 Sudan 23 . . . 
 
 , . .75 
 
 5.81 
 
 8.11 
 
 10.3 
 
 Common . . . 
 
 . .66 
 
 — 
 
 — 
 
 9.3 
 
 Sweet 
 
 . .65 
 
 4.68 
 
 7.31 
 
 7.6 
 
 Tift 
 
 ,. .63 
 
 — 
 
 — 
 
 7.9 
 
 * Unreplicated yields from a single cutting 
 made July 14. ^ 
 
 What are the 
 requirements of 
 sudangrass? 
 
 Sudangrass does best in fertile soils, 
 where the weather is warm and the grow- 
 ing season relatively long. It is severely 
 injured or killed by light frosts. 
 
 The irrigated valleys are well suited 
 for sudangrass. The upper altitude limits 
 for profitable production appear to be 
 4,000 to 5,000 feet in northern California, 
 
 [4] 
 
Here are the results of a sudangrass variety trial, held at Davis. The plot on the left is an experi- 
 mental selection; next is the early-maturing, and shorter, common sudan; then sweet sudan; and 
 on the right, sudan 23. Improved varieties show more vigorous growth. 
 
 and 5,000 to 6,000 in the southern part 
 of the state. 
 
 It is grown on a wide variety of soils, 
 ranging from heavy clay to light sands, 
 but yield is reduced on sandy soils. Good 
 drainage is essential and even small 
 amounts of alkali will reduce yields. 
 
 The ability of sudangrass to endure 
 drought is equal to that of the best sor- 
 ghum varieties, but growth is propor- 
 tional to the amount of water available. 
 The plant has an extensive root system 
 and will continue growth as long as the 
 roots are able to reach moist soil. 
 
 The soil should be 
 well prepared. 
 
 A well prepared seedbed is necessary 
 for good germination. Best results will 
 be obtained by plowing in the fall or early 
 winter and allowing the land to remain 
 rough until spring. 
 
 The most critical period is during ger- 
 mination and stand establishment, so 
 conservation of moisture is essential— 
 especially when the crop is grown under 
 dry-land conditions. 
 
 Before planting, disk the soil to kill 
 weeds; follow with a spike-tooth harrow 
 and a flat drag or cultipacker to smooth 
 the surface and conserve moisture. These 
 operations should follow each other in the 
 shortest possible time, to avoid drying 
 out the surface. 
 
 When to plant. Sudan requires a 
 warm soil for good germination. Seeding 
 may be done from mid-April to July. 
 Planting on dry-land should be made 
 earlier than under irrigation, so the root 
 system can become established while 
 moisture is still available near the sur- 
 face. Delaying seeding until June or July 
 reduces yield because of the short grow- 
 ing season. Treatment with new, improved 
 Ceresan, or Ceresan M, prevents seed rot 
 on cold, heavy soil, and also controls 
 covered kernel smut. 
 
 How to plant. The most satisfactory 
 method of seeding is the grain drill, set 
 to discharge seed from 2 to 3 inches be- 
 low the surface. Shallow seeding is best 
 on heavy soil; deeper seeding may be 
 required on sandy soil. Broadcasting and 
 harrowing to cover the seed is less satis- 
 factory. 
 
 Going over the land with a cultipacker 
 immediately after seeding helps to con- 
 serve surface moisture and is advisable 
 on most soils. 
 
 Seeding rates can be varied greatly 
 without appreciably influencing yields, 
 but general farm practice has shown that 
 seeding at a rate of 15 to 20 pounds per 
 acre is satisfactory under irrigation. On 
 dry-land, seeding rates are usually re- 
 duced to 12 or 15 pounds per acre, and 
 in wide rows, 3 to 6 pounds are adequate. 
 
 Plants tend to grow more coarse if 
 planted at lighter seeding rates. 
 
 [5] 
 
This is a seed increase plot of tift sudan, grown under irrigation at the Agronomy Division at Davis. 
 
 Sometimes 
 fertilizing 
 will help. 
 
 Fertilizing sudangrass with nitrogen is 
 often profitable on newly leveled land 
 under irrigation. Applications of about 
 150 pounds ammonium sulfate per acre 
 or equivalent amounts of other nitrogen 
 fertilizers may be made. If sudangrass is 
 sown on land used for the same crop in 
 the previous year, fertilization rates 
 should be about doubled, or 300 pounds 
 per acre of ammonium sulfate or its 
 equivalent. Sudangrass following alfalfa, 
 irrigated pastures, or on dry-land will 
 probably not require fertilization. Some 
 of the reddish colored soils in the Sacra- 
 mento Valley may require phosphorus 
 in addition to nitrogen. 
 
 Keep weeds ^ 
 
 down by 
 using 2,4-D. 
 
 Most of the troublesome annual weeds 
 can be eliminated during seedbed prepa- 
 ration for sudangrass. Certain summer 
 growing broadleaf weeds like star thistle 
 and ragweed can be controlled with 
 2,4-D weed spray. Applications are made 
 when the grass is about six inches high 
 using % pound of acid equivalent per 
 acre in 30 to 60 gallons of water. Live- 
 
 stock are not injured by 2,4-D and there- 
 fore sudangrass for pasture can be 
 sprayed. Precautions must be taken to 
 avoid injury to susceptible crops in 
 adjacent fields. 
 
 Weeds are usually crowded out of 
 Sudan, and seldom become a problem 
 unless the stand is poor. However, water- 
 grass is a vigorous competitor on irri- 
 gated land. Because watergrass is quite 
 palatable, it presents little problem when 
 sudangrass is grazed. When sudangrass 
 is to be used for seed watergrass can be 
 troublesome. 
 
 The good and 
 the bad of 
 sudangrass for • • • 
 
 Pasture. Sudan pasture is used for all 
 classes of livestock. Rate of gain for beef 
 cattle or sheep is equal to other kinds of 
 green feed. Pasturing should be delayed 
 until the stand is at least 18 to 24 inches 
 high. The best yields are obtained if the 
 field is subdivided into various pastures, 
 and grazed in rotation. 
 
 Irrigation should be frequent enough 
 to keep the plants in a healthy, vigorous 
 growing condition. 
 
 Poisoning from excessive concentra- 
 tion of prussic (hydro cyanic) acid in 
 sudangrass has caused considerable con- 
 cern to livestock men in certain areas in 
 
 [6] 
 
the northern part of the United States. 
 The problem has been one of infrequent 
 occurrence in California, and in south- 
 ern states. A number of losses occurred 
 in the Sacramento Valley on dry-land 
 Sudan in 1949. 
 
 High concentrations of prussic acid 
 are more likely to occur in sudan that is 
 growing slowly. For this reason, early 
 spring or late fall growth is more likely 
 to cause trouble. 
 
 Precautions for avoiding injury are: 
 
 1. Use only pure sudan seed. (The sor- 
 ghums and Johnsongrass contain 
 higher concentrations of prussic acid 
 than sudangrass) . 
 
 2. Allow 18 to 24 inches of growth be- 
 fore grazing. 
 
 3. Graze drought or frost-injured sudan 
 cautiously. 
 
 4. Do not allow excessively hungry 
 cattle to feed on sudan pasture. 
 
 Bloat from grazing succulent alfalfa, 
 Ladino clover, or other legumes has been 
 successfully overcome by night grazing 
 of sudangrass. Farmers who have had 
 bloat problems might consider the use 
 
 of sudan in addition to other irrigated 
 pastures. 
 
 Hay. Sudan hay is equivalent in feed- 
 ing value to other non-leguminous hay, 
 such as cereal. The protein content is 
 much less than that of alfalfa, but is high 
 enough to keep stock in a healthy condi- 
 tion without the use of other feeds. 
 
 Time fo cut. For best production, cut 
 sudan hay shortly after it begins heading. 
 Because the stems are large and juicy, 
 the hay should be dried in the swath or 
 windrow until it becomes dry enough to 
 prevent heating— this may require several 
 days. 
 
 Little leaf shattering occurs with sudan. 
 Some farmers find chopping is desirable 
 before feeding. 
 
 Seed production of sudangrass is be- 
 coming increasingly important in Cali- 
 fornia because of high yields and the 
 excellent quality of the seed produced in 
 arid regions. 
 
 Land selected for sudan seed pro- 
 duction should be free from Johnsongrass 
 and morning glory because the seed from 
 these two weeds are almost impossible to 
 
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 Here is a picture of WHAT NOT TO DO. The sudangrass in this pasture has been grazed much too 
 short, and recovery will be difficult. Close grazing such as this tends to reduce yields considerably. 
 
 [7] 
 
separate from the sudan seed. Both of 
 these plants are secondary noxious 
 weeds in CaHfornia. 
 
 Planting. Nearly all sudangrass 
 seed is produced from close-drilled plant- 
 ings, and mostly under irrigation. One 
 pre-irrigation plus 1 or 2 later irrigations 
 are usually sufiicient to make a good seed 
 crop. 
 
 Plantings made primarily for seed pro- 
 duction should be made between June 1 
 to 15, if the crop is not to be grazed. 
 About 110 days are required to produce 
 a seed crop from plantings made at this 
 date. 
 
 Planting earlier, and grazing or har- 
 vesting the hay before letting the stand 
 go to seed is hazardous because grazing 
 too long, or harvesting too late may delay 
 ripening of the seed into the fall. This 
 will result in danger from wind and rain, 
 as a longer time is required to ripen the 
 seed during the cooler fall weather. Also, 
 the crop is subject to shatter losses from 
 wind and rain over a longer period of 
 time. 
 
 Cut the seed crop when the major- 
 ity of the heads on the main portion of 
 the stem are ripe. Delaying harvesting 
 until after this time may result in ex- 
 cessive shattering. 
 
 The crop should be swathed and al- 
 lowed to cure for about a week—a 6- to 8- 
 inch stubble will hold the plants off the 
 ground and permit air circulation and 
 
 rapid drying. Harvesting from the swath 
 is done with the combine. Cylinder speed 
 should be reduced enough to prevent re- 
 moval of coverings from too much of the 
 seed. 
 
 Direct combining of standing sudan is 
 not recommended. This method requires 
 the plants to be more mature before har- 
 vesting and results in excessive shatter- 
 ing. Also— green pieces of stems and hulls 
 are not separated readily from the seed, 
 and may cause heating and damage to 
 germination. 
 
 Hazards, Aside from contamination 
 by Johnsongrass and morning glory, the 
 greatest hazard to seed quality is low 
 germination. This may be caused by frost, 
 immature seed, excess moisture and heat- 
 ing of seed, or too high temperatures 
 when the seed is artificially dried. 
 
 All of these are avoided by managing 
 the seed crop so it can be harvested in 
 late August or early September. 
 
 Expected yields. Seed yields range 
 from 600 to 3000 pounds per acre. 
 
 A good seed producer can expect to 
 obtain about 1800 pounds of sweet sudan 
 seed per acre; somewhat less for sudan 
 23, under favorable conditions. 
 
 The fact that the state average for seed 
 yields is around 800 pounds per acre in- 
 dicates that losses from shattering, or 
 improper management run very high. By 
 cutting losses, sudan seed can be a profit- 
 able cash crop for California farmers. 
 
 Cooperative Extension work in Agriculture and Home Economics, College of Agriculture, 
 
 University of California, and United States Department of Agriculture cooperating. 
 
 Distributed in furtherance of the Acts of Congress of May 8, and June 30, 1914. 
 
 J. Earl Coke, Director, California Agricultural Extension Service. 
 
 15m-5,'50(B9573)WP