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Sorghum halepense (L.) Pers.

Poaceae
Johnsongrass

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 unpublished.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. References

Uses

An excellent grass for hay and pasture in the southern United States from Alabama to Texas. Palatable and nutritious when fed early, comparable to timothy as hay, and when properly fertilized and cut in the boot stage, ranks next to alfalfa and ahead of oat and soybean hays for feeding dairy cows. A system of grazing johnsongrass and roughpeas is often used to good advantage. Elsewhere the seeds are eaten in times of scarcity. Often becomes a troublesome weed in rich bottomlands and black soils. Sometimes produces enough cyanogenic compounds to poison grazing animals. Very difficult to eradicate. In some places the root is used as a substitute for sarsaparilla (Smilax sp.).

Folk Medicine

Reported to be cyanogenetic, demulcent, depurative, diuretic, poison, and tonic, johnsongrass is a folk remedy for blood and urinary disorders (Duke and Wain, 1981).

Chemistry

Per 100 g, the forage is reported to contain 9–15.5 g protein, 1.8–3.4 g fat, 34.5–44.6 g non-fiber carbohydrate, 25.2–30.1 g fiber, 13.3–18.5 g ash, 1,290–1,340 mg CaO, 490–910 mg P2O5 (C.S.I.R., 1948–1976). Hager's Handbuch reports that the wild forms contain various quantities of the cyanogenetic dhurrin (C14H17NO7) as well as b-amyrin. The nutritional values they report make no sense to me but here they are: 0.3% fat, 1.53% protein, 7.43% starchy substances, 0.22% glucose, 10.78% cellulose, and 1.94% minerals (List and Horhammer, 1969–1979). On the contrary, Miller (1958) reporting on >40 analyses (DM 85.6–93.7%), found CP ran from 5.5–15.4% (mean of 41 = 7.7), EE from 1.3–3.0% (mean of 41 = 2.1), CF from 28.0–37.7% (mean of 41 = 33.3%), ash from 5.9–11.9% (mean of 43 = 8.8), and NFE 41.3–51.0% (mean = 48.1), Ca 0.18–1.06% (mean of 15 = 0.81), P 0.23–0.49% (mean of 15 = 0.31), K from 1.21–1.52 (mean of 5 = 1.35), Mg from 0.30–0.42% (mean of 6 = 0.35%), and carotene from 31–62 ppm (mean of 14 = 37).

Toxicity

Under certain conditions, the plant, if grazed, may cause cyanide poisoning. The pollen may induce hay fever.

Description

Stout, erect, perennial, spreading by vigorous extensively long-creeping scaly rhizomes; culms 5–15 dm tall, sometimes to 3.5 m; leaves numerous; blade long and slender, less than 2 cm broad; panicle open, 15–50 cm long; sessile spikelet 4.5–5.5 mm long, ovate, appressed-silky; awn readily deciduous, 1–1.5 cm long, geniculate, twisted below; pedicellate spikelet 5–7 mm long, lanceolate; tip of pedicel on seed knob-shaped. Fl. summer–fall. Seeds 260,190/kg.

Germplasm

Reported from the Mediterranean Center of Diversity, johnsongrass, or cvs thereof, is reported to tolerate frost, hydrogen fluoride, high pH, heavy soil, low pH, smog, weeds, and waterlogging (tolerates periodic flooding) (Duke, 1978). In shaded conditions seeds do not germinate and seedlings grow poorly. In fields, seeds from the current season are believed to have low germination, while seeds that have lain in the soil for one year will sprout readily. Still seeds are known to germinate from 15 cm deep, but most seedlings arise from the top 7 cm. There are at least 55 morphologically distinct vegetative types in the US alone (Holm et al., 1977). Some cvs of johnsongrass include: 'Mississippi Fine Stem' , developed in Mississippi, produces 130 to 180 culms per plant, 60–120 cm tall, up to 0.3 cm in diameter, the largest culm never getting as large as allowed in grade I hay; very leafy, relatively low seed production, used as source material in breeding programs. 'Mississippi Persistent', developed in Mississippi, produces 80 to 120 culms per plant, up to 1.6 m tall, 0.3–0.6 cm in diameter, rather compact base with very slowly spreading rhizomes, persistent under mowing, withstands 6 clippings in 2 years. SORGRASS (Sorghum halepense x S. bicolor, including S. halepense x S. sudanense and S. almum), used for both grain and forage. The forage types resemble S. sudanense, but may vary in vigor, coarseness of plant, sweetness and time from seeding to maturity. 'DeSoto', developed in Texas, is vigorous, intermediate in size, with broad flat leaves, large open panicles and short terminal rhizomes. 'Mississippi ISJ', developed in Mississippi, a selection from F6 between sorgo and johnsongrass, producing 20–40 culms per plant, 3–4 m tall, 0.8–1.3 cm in diameter, with slowly spreading rhizomes, providing 2 cuttings per year; total carbohydrate content ca 10–14%; seed set approximately 50%, produces extremely well under irrigation and fertilization. 'Mississippi SJ-2', developed in Mississippi, selection from F6 made on basis of grass-type habit and carbohydrate content (ca 14%), very leafy, produces 40–90 culms per plant, 1–1.6 m tall, up to 0.8 cm in diameter, self-fertile and good seed producer, may be cut twice per season. 'Perennial Sweet', developed in Texas, is a synthetic tetraploid, with short thick rootstock, a weak perennial, more profitably grown as an annual, as palatable as Sweet Sudangrass and seed very similar to it; glumes chocolate to mahogany in color; seeds persistent and plant mostly tan. (2n = 20, 40)

Distribution

Native to the Mediterranean regions of North Africa, South Asia, and southern Europe, extending to Arabia and India. Introduced to many subtropical and tropical regions of the world. Introduced to United States about 1830 from Turkey; now naturalized from Massachusetts to Florida, west to Iowa and Kansas and then southward to Texas and southern California. According to Holm et al. (1977) johnsongrass ranges as a weed from 55°N to 45°S, reported as a weed in 30 crops in 53 countries.

Ecology

Ranging from Cool Temperate Steppe to Wet through Tropical Very Dry to Wet Forest Life Zones, johnsongrass is reported to tolerate annual precipitation of 0.9 to 42.9 dm (mean of 49 cases = 10.7), annual temperature of 8.3 to 27.8°C (mean of 49 cases = 18.7), and pH of 4.9 to 8.2 (mean of 42 cases = 6.8). Adapted to warm humid summer-rainfall areas in subtropics, not growing well in strictly tropical areas. Naturalized to rich bottomlands and black soils, especially in the Cotton Belt in southern US. Common on open ground, old fields, cultivated fields, and waste places. Adapted to a wide range of soil types, including upland clay, but seems to do best on porous fertile lowlands and river bottoms. Does well on heavy clay soils of relatively high fertility and water holding capacity. Not winter-hardy in cold climates. Temperatures below 13°C tend to inhibit flowering. Classified as a short day plant.

Cultivation

Initially propagated from seed. Should be seeded in early spring on firm, well-prepared seedbed, as early as December in the South. Seeding rate 11–28 kg/ha. Removal of the glume has given 95% germination in some experiments with dormant seeds (Holm et al., 1977). Sparve stands may be thickened by a thorough disking in the spring. Also reproduces by the fleshy underground rhizomes. Under favorable conditions, the rhizomes contain large amounts of stored food and form the basis for the perennial habit through their capacity to survive moderately severe winters. An average plant can produce ca 20 m of rhizomes per season. Most meadows are established naturally following the gradual spread among cotton and other row crops until cultivation became unprofitable. To establish a meadow, seed broadcast or drilled in spring or early summer at rate of 20–35 kg/ha. Sometimes sown in mixtures with sweet clover or roughpeas. Johnsongrass responds to fertilization on most soils, especially on eroded and depleted ones. Application of N fertilizer up to 1075 kg/ha has been recommended. Economical increases in forage amounting to 9 MT/ha has resulted when N is applied. Planting with a legume is another way to increase the nitrogen content in soil for johnsongrass.

Harvesting

Johnsongrass is cut for hay when flower-heads are still in the boot stage.Coarse stems dry slowly and thorough curing is necessary to produce good hay. Tends to become sod-bound after 2–3 years and may be renovated by plowing in spring and overseeding with soybeans, cowpeas, or sweet clover. May be cut for hay 2 or 3 times/season. Seeds are dormant when first mature and require a number of months to after-ripen. Even when they do not germinate completely until alternating cold-warm temperatures are available in a warm area. Most johnsongrass seed is machine harvested in southern US (Alabama to Texas). Eradication is sometimes a serious problem. Pasturing has been recognized as one method to control this grass. Mowing gives much the same effect. Disking 5–7 times a season is more effective for the seedlings. An average plant produced from a single seed can produce more than 170 culms, ca 20 m of rhizomes and 1.7 kg of seed per season, depending on soil fertility, moisture, and space. Frequent mowing or grazing through the growing season, exhausting the rootstock, is the best means of eradication. According to the Wealth of India (C.S.I.R., 1948–1976), 4-CPA, TCA, Dowpon, and Naphta may be useful in controlling weedy johnsongrass. But for effective control, they recommend application of 33 kg/ha TCA (trichloroacetic acid) with six cultivations, followed by ca 11 kg/ha 2,4-D (if the treatment is applied to the weed infested field 100 days before wheat is sown, there is no observable residual toxicity). Sodium azide (ca 125 kg/ha) and methyl bromide has also been evaluated.

Yields and Economics

Cultivars average 1–20 MT/ha forage. Seed yields may be small in some hybrids and cvs, up to 1.7 kg per plant. Seeds yield range from 188 to 502 kg/ha, with 314 kg/ha considered good. Johnsongrass hay was valued at approximately $50/MT in 1978 (Bennett, 1981).

Energy

According to the phytomass files (Duke, 1981b), annual productivity ranges from 2 to 19 MT/ha. One estimate puts the weight of the rhizomes alone at 33 MT. Nineteen MT hay/ha is reported (Duke, 1978). These yields are much higher than those reported by Bennett, who puts unfertilized yields at 0.5–1.4 MT/ha/yr, and fertilized rainfed yields at 2.7–4.9 MT/ha/yr.

Biotic Factors

Leaves often splotched with purple due to a bacterial disease. Bacteria known to attack johnsongrass include the following: Pseudomonas andropogonis, Ps. holci, Ps. syringae, and Xanthomonas holcicola. Fungi attacking johnsongrass include: Alternaria tenuissima, Apiospora camptospora, Ascochyta sorghi, A. sorghina, Balansia andropogonis, Cercospora sorghi, Cladosporium graminum, Colletotrichum falcatum, C. graminicola, Colletotrichopsis graminicola, Epicoccum neglectum, E. nigrum, E. purpurascens, Fusarium graminearum, Fusicladium sorghi, Gibberella fujikurai, G. zeae, Gloeocercospora sorghi, Hadrotrichum sorghi, Helminthosporium maydis, H. sorghicola, H. turcicum, Leptosphaerulina argentinensis, Meliola megalopoda, M. andropogonis, Metasphaeria panicorum, Monascus purpureus, Mycosphaerella tulasnei, Nigrospora sphaerica, Ophiobolus acuminatus, Phoma insidiosa, Phyllachora sorghi, Phyllosticta sorghina, Puccinia graminis, P. purpurea, Periconia byssoides, Ramulispora sorghi, Sclerospora macrospora, Thanatephorus cucumeris, Titaeospora sorghi, Trichometasphaeria turcica, and Uromyces andropogonis. It is also attacked by the leaf-gall and maize dwarf mosaic viruses. It is parasitized by the flowering plants Striga lutea and S. euphrasioides. Nematodes isolated from johnsongrass include Pratylenchus zeae and Tylenchorhynchus martini. A serious weed, johnsongrass can cause 25–50% reduction in ratoon sugar yields, 12–33% in corn, and ca 5–20% in soybean. It is one of the "big 3" weeds in cotton in Greece, Mexico, and Venezuela, sugarcane in Argentina, Australia, Fiji, Pakistan, the US, and Venezuela, corn in Chile, Greece, US, and Yugoslavia, citrus in Mexico and Venezuela, and vineyards in Australia. It is reported that extracts or exudates of Johnsongrass can inhibit germination of seedling growth of clover, crownclover, and johnsongrass itself. Johnsongrass is an alternative host for Botryosphaeria sp. and Puccinia purpurea and of viruses causing rice leaf gall, cornleaf gall, stripe disease of rice, sugarcane mosaic, maize dwarf mosaic, beet yellows, and wheat streak mosaic (Holm et al., 1977).

References

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