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Sorghum sudanense (Piper) Stapf

Poaceae
Sudangrass

Source: James A. Duke. 1983. Handbook of Energy Crops. unpublished.


  1. Uses
  2. Folk Medicine
  3. Chemistry
  4. Toxicity
  5. Description
  6. Germplasm
  7. Distribution
  8. Ecology
  9. Cultivation
  10. Harvesting
  11. Yields and Economics
  12. Energy
  13. Biotic Factors
  14. Chemical Analysis of Biomass Fuels
  15. References

Uses

An important annual summer grass planted for pasture, silage, green chop and hay. Importance of sudangrass is expected to increase with sorghum-sudangrass hybrids yielding more forage than either parent. In the US Gulf States, the hybrids are among the most popular summer annual grazing crops.

Folk Medicine

No data available.

Chemistry

Based on 169 analyses, Miller (1958) reports that DM in the dry forage ranged from 78.1–95.0% (mean of 88.9%). On a zero-moisture basis, CP ranged from 6.5–23.0% (mean of 171 = 12.7), EE from 0.8–6.7 (mean of 170 = 2.2), CF 21.7–37.9 (mean of 171 = 28.9%), ash from 4.8–13.1 (mean of 171 = 9.6) and NFE from 37.4–51.9 (mean of 46.6), Ca from 0.38–1.12 (mean of 28 = 0.56%), P from 0.20–0.93 (mean of 38 = 0.31), K from 0.88–2.74% (mean of 21=1.54), Mg from 0.31–0.77 (mean of 21 = 0.40), Fe from 0.011–0.025 (mean of 16 = 0.017%), Mn from 66–155 ppm (mean of 19 cases = 93), and Cu 37 ppm, S 0.04–0.08% (mean of 5 = 0.06%), Na from 0.01–0.03 It (mean of 6 = 0.02), cobalt 0. 1 ppm, and carotene 5.5 ppm. DM in the fresh or green roughage ranged from 8.4–35.4% (mean of 95 cases = 21.8%). On a zero moisture basis, CP ranged from 4.1–23.2 (mean of 97 11.2%), EE from 1.4–5.0% (mean of 97 = 2.5%), CF from 18.1–42.6% (mean of 97 = 44.3%), Ca from 0.32–0.67% (mean of 18 = 0.43), P from 0.18–0.79 (mean of 18 = 0.4), Cu = 36 ppm, K from 1.45–3.05% (mean of 10 = 2.14), Mg from 0.30–0.41 (mean of 11 = 0.35), Fe from 0.013–0.060 (mean of 6 = 0.021%), Mn from 36–101 ppm (mean of 6 = 81), S from 0.03 to 0.20% (mean of 9 = 0.11%), and Co 0.13 ppm, carotene from 53 to 219 ppm (mean of 14 cases = 182). Continuing their studies that showed that grasses accumulate sucrose during the light period, with lows (ca 1–3%) at ca 6 a.m. increasing until ca 6 p.m.when sucrose may be 2–5 times higher Lechtenberg et al. (1973) report the following about sudangrass: Sucrose concentration in sudangrass herbage varied from 1.8% of the dry matter at 6 am. to 5.8% at 6 pm. Starch increased from 6.6 to 8.8% in the same period. Half of the daily increase in carbohydrate disappeared between 6 P.M. and 12 midnight. The diurnal trends in leaves were similar to those observed in herbage. Nitrogen fertilization (140 kg/ha) reduced the average total carbohydrate concentrations from 16.6 to 14.8% but did not change the magnitude of diurnal trends. Starch concentration declined from 9.9 to 5.9% of the dry herbage and sucrose increased from 1.2 to 6.6% during the 16-day sampling period. This change was more pronounced in N-deficient sudangrass.

Toxicity

Under certain conditions, this grass can develop lethal concentrations of HCN. High levels of available soil N and low levels of P seem to increase the poison (Watt and Breyer-Brandwijk, 1962). Dhurrin is also reported (List and Horhammer, 1969–1979). Nitrate poisonings and photosensitivities are also reported.

Description

Tufted annual grass with heavy tillering but no rhizomes; culms slender, to 3 m tall, 3–9 mm in diameter; leaves numerous, up to 100 per clump, long, broad to narrow; panicles open, twice as long as broad, 15–75 cm long; spikelets not easily shed making seeds easily collected; glumes (hulls) around seed-buds with bristle-shaped tips, often purplish when in flower; bristles break off in threshing; seeds pale yellow when ripe. Seeds 121,275/kg. Sudangrass only develops fibrous roots and never becomes a noxious weed.

Germplasm

Reported from the African Center of Diversity, sudangrass, or cvs thereof, is reported to tolerate anthracnose, disease, drought, fungus, grazing, high pH, heavy soil, heat, laterite, sand, virus, and weeds (Duke, 1978). Harlan and deWet (1972) suggest that sudangrass is a non-shattering segregate from a hybrid or hybrids involving S. virgatum and a sorgo type of cultivated sorghums. Several cvs have been developed with more disease resistance, more leaves, sweeter stems, later maturity, and less HCN than common cvs. Sorghum-sudangrass hybrids resemble sudangrass in habit, but are taller with larger stems and leaves and generally better yields. Some cultivars are: 'Sudan 23' or 'California 23'; a heavy yielding strain suitable for irrigated areas in the Southwest; 'Cumberland', widely adapted to Southeast US and producing fine stems, long narrow leaves, spreading panicles, and high yields; 'Greenleaf', vigorous, leafy, producing many juicy stems, maturing later than other cvs, producing high yields under favorable conditions, somewhat resistant to leaf blight and anthracnose, resistant to some bacterial foliage diseases, and best adapted to Central latitude of Midwest US; 'Piper' has good vigor, early maturity, pithy stems, low level of HCN, some resistance to leaf blight and anthracnose, developing more rapidly than 'Tift'; 'Tift' is rather leafy because extra shoots grow from most of lower joints of stem, mostly pithy stems, plant tan-colored, seeds mixture of chocolate and tan, matures slightly later than other sudangrasses and is more disease resistant, best adapted to humid southeastern US and parts of Texas; 'Wheeler' produces vigorous seedlings and matures early, generally higher yielding than most common strains, but is rather stemmy and susceptible to disease. (2n = 20)

Distribution

Originally from the Sudan where it is a weed of cultivated land, and only occasionally grown as fodder. Introduced from Africa to US in 1909, and from US introduced to South America, Australia, South Africa, Central and North Europe. In US grown mostly from southern Texas to Minnesota and North Dakota in the central grassland regions.

Ecology

Ranging from Cool Temperate Steppe to Wet through Tropical Very Dry to Dry Forest Life Zones, sudangrass is reported to tolerate annual precipitation of 2.0 to 21.4 (mean of 37 cases = 9.8), annual temperature of 7.8 to 27.5°C (mean of 37 cases = 17.4), and pH of 4.9 to 8.2 (mean of 32 cases = 6.6). Sudangrass has a very wide range of adaptation, growing where summers are hot with a fair summer rainfall. Crop is very drought-resistant. Plants grow rapidly from late seeding. Not suited to cool humid temperate regions or to more humid regions in subtropics and tropics. Most favorable temperature for growth ranges from 25–30°C, with minimum ca 15°C. Sudangrass does not tolerate frost and is killed when the temperature drops to 3–5°C below the freezing point. Grows well under irrigation in hot dry regions. Rarely grown above 2700 m in southwest US, and less so farther north. Adapted to wide range of soils from heavy clays (not cold and wet) to sands, but requires fertile land to give heavy yields. Does not tolerate alkaline, saline, or solonetz soils.

Cultivation

Sudangrass is an excellent seed producer in all but humid areas. Seed broadcast or close-drilled. Low seed rates give as good yields as higher rates because of heavy tillering. Rates vary in different areas: in US, dryland planting, 20–25 kg/ha broadcast, humid 12–15 kg/ha broadcast or 3–8 kg/ha drilled; in India, 16–24 kg/ha broadcast or drilled; in Kenya, 20–30 kg/ha broadcast or drilled. When drilled in rows, spacing between rows may vary from 18 cm in Kenya to 90–105 cm elsewhere. A firm seedbed is desirable. Seed should be sown when soil is warm in late spring or early summer. Seeds may be drilled to a depth of 1–3 cm. Seedlings emerge in less than a week when conditions are warm and moist (Bogdan, 1977). Usually seeded alone in low-rainfall areas; often combined with soybeans in more humid areas. Also intercropped with cowpea and velvet beans. In India, often grown in rotation with tobacco, cotton, sugarcane, and groundnuts. In Africa, may follow groundnuts. In US, South Africa, and Australia, often precedes fallow or leguminous crop. Fertilizer requirements of sudangrass similar to those of annual grass crops or corn. Sudangrass grows rapidly; sufficient nitrogen at planting time helps insure establishment and hasten development. On any soil, some complete fertilizer is advisable for higher yields. Usual recommendation per ha in the Northeast is 165–275 kg of 10-10-10; in Midwest, 220–330 kg of 3-12-6 or similar ratio, and in irrigated lands of the West, 33–66 kg of nitrogen. Phosphorus and potassium should be applied if deficient. Barn-yard manure is useful also: In India ca 20 MT/ha is recommended. It also responds well to sewage irrigaton. Hybrid sorghum seed are produced from female plants that are male sterile, that is, the flowers of such plants do not produce viable pollen, and so are not self-pollinating. Male flowers of another cv are grown in rows alongside the female rows, thus providing the pollen for producing the hybrid seed (Reed, 1976).

Harvesting

Crop should be rotation grazed with other pastures or divided into subdivisions that are rotated. Sudangrass and sorghum-sudangrass hybrids are usually ready for grazing 5 or 6 weeks after planting. Plants are palatable and readily eaten at the early heading stage, but regrowth will be better when the crop is grazed before heading starts. To avoid HCN poisoning, sudangrass should not be pastured until it is 45–60 cm high. When grazing is begun, stock sudangrass heavily so it will be grazed down before heading starts. If fields reach 100 cm or more before livestock can graze them, crop should be harvested for silage. For green chop, cut plants down to a 15 cm stubble, making the first cut just before the heading stage to insure good regrowth. Highest hay yields are obtained when crop is harvested with seed in the soft-dough stage. Because curing is difficult at this stage, it is more practical to harvest at boot stage when plants are 75–100 cm tall. Use of a hay crusher will reduce drying time and give higher quality hay. Feed value of good sudangrass hay is about equal to that of millet, timothy, johnsongrass, and other non-legume roughages. From 2–4 cuttings can be made per season depending on region.

Yields and Economics

Total DM production is highest when harvested at flowering stage, yielding up to 27.5 MT/ha for sudangrass; 28 for sudangrass hybrids; and 27 for sorghum-sudangrass hybrids. Fresh forage yields may exceed 88 MT/ha when fertilized with 280 kg N and 140 kg P2O5/ha, yielding 60% more than unfertilized controls. Even in Ukrania, sudangrass yields 30 MT green forage/ha (Dyachenko, 1977). Though it is reported to fare poorly on solonetz soils, Lazarchuk (1977) has obtained 10–30 MT green forage, with drainage, irrigation, and application of 10 MT/ha gypsum. Ostapov and Sidenko (1976) reported that sudangrass yielded 51.4 MT fresh fodder/ha following winter wheat, 49.6 following a wheat/oats/peas mixture, 44.8 following winter wheat/maize, and 46.2 MT/ha following rye/vetch/ maize, while sorghum yielded 7.2, 6.3, 5.5, and 5.7 MT/ha respectively. Spring barley following the sudangrass averaged grain yield of 2.5, 2.2, 2.0, and 2.0 respectively. Multiple cropping decreased the yields of subsequent crops in Ukrania (Ostapov and Sidenko, 1976). Dubenko and Yurchenko (1980) reported fresh fodder yields of ca 40 MT/ha and hay yields of nearly 12 MT/ha in new cvs ('A-6', 'A-24') for low rainfall areas, compared to 37 and 11 for the standard cv 'Mironovskaya'. Given no fertilizer, sudangrass averaged ca 16 MT fresh fodder/ha and 220 kg DCP (= digestible crude protein), given 40 MT FYM (farmyard manure) it yielded 19 MT fresh fodder/ha and 300 kg DCP. Given the manure plus 90 kg N, 60 kg P2O5 and 60 kg K2O, it yielded 23 MT fresh fodder and 420 kg DCP (Kalashnikov et al., 1980). In the Soviet Samarkand region, seed yields were 200–220 kg/ha and hay yields (in one cut) ca 15 MT (Safarov and Ismailov, 1980). Cv 'Penzenskaya Rannespelaya' gave seed yields of 1200–1500 kg/ha (Epifanov and Odintsova, 1976). Forage yields for silage was 40–45 MT/ha per season. Average US seed yields are 600–3,000 kg/ha; India, 250–400 kg/ha; Kenya 500–1,000 kg/ha. Seed, ripening unevenly, are best cut with binder in hard dough stage and shocked, and threshed later when dry. Although good silage can be made, grain sorghums and corn yield better. About 1,300,000 ha planted annually in US.

Energy

According to the phytomass files (Duke, 1981b), annual productivity ranges from 1 to 40 MT/ha.

Biotic Factors

Sudangrass suffers some insect and bird predation. Some cvs are partially resistant to bird damage and seed is available in Kenya with bitter grain. Fungi reported as attacking sudangrass include the following: Ascochyta sorghi, A. sorghina, Blakeslea trispora, Cercospora sorghi, Cladosporium graminum, C. herbarum, Colletotrichum graminicola, Darluca filum, Fusarium avenaceum, F. equiseti, F. oxysporum, F. scirpi var. acuminatum, Gloeocercospora sorghi, Hadrotrichum sorghi, Helminthosporium catenarium, H. sativum, H. sorghicola, H. sudanense, H. turcicum, Macrosporium ornatissimum, Phyllosticta sorghina, Phoma insidiosa, Puccinia purpurea, Pyricularia grisea, Pythium arrhenomanes, P. dabaryanum, Ramulispora sorghi, Sclerospora graminicola, S. sorghi, Sclerotium bataticola, Sphacelotheca cruenta (Kernel smut), S. reiliana (Read smut), S. sorghi, (Loose smut), Titaeospora andropogonis, Trichometasphaeria turcica, Uromyces cligyni. Bacteria causing diseases on sudangrass include Pseudomonas andropogonis, P. syringae, and Xanthomonas holcicola. Plants are parasitized by species of Striga (S. lutea, S. hermonthica), and are sometimes used as a trap crop. Striga can be a serious menace. Nematodes isolated from sudangrass include the following: Helicotylenchus dihystera, Meloidogyne incognita, M. incognita acrita, M. javanica, Pratylenchus scribneri, P. zeae, and Radopholus similes.

Chemical Analysis of Biomass Fuels

Analysing 62 kinds of biomass for heating value, Jenkins and Ebeling (1985) reported a spread of 17.39 to 16.31 MJ/kg, compared to 13.76 for weathered rice straw to 23.28 MJ/kg for prune pits. On a % DM basis, the plant contained 72.75% volatiles, 8.65% ash, 18.60%fixed carbon,44.58% C, 5.35% H, 39.18% O, 1.21% N, 0.08% S, 0.13% Cl, and undetermined residue.

References

Complete list of references for Duke, Handbook of Energy Crops
Last update Friday, January 9, 1998 by aw