Sorghum

Description

 

Crop Details

The following are the crop details for sorghum:

Scientific name: Sorghum bicolor

Order: Poales

Family: Poaceae (formerly known as Gramineae)

Genus: Sorghum

Local names: Swahili: mtama; Spanish: sorgo; French: sorgho; German: sorghum; Italian: sorgo; Portuguese: sorgo; Chinese (Mandarin): 高粱 (gāo liáng); Japanese: モロコシ (morokoshi); Hindi: ज्वार (jwar); Arabic: الذرة السوداء (al-dhurrah al-sawda)

General Information

Sorghum is a type of cereal grain that belongs to the grass family Poaceae (formerly known as Gramineae). It is one of the top five cereal crops in the world, and is widely grown in Africa, Asia, and the Americas.

Sorghum is a tall, erect, annual grass that typically grows to a height of 1-2 meters. It has long, narrow leaves and produces large, compact clusters of grain on top of its stems. The grains are typically small and round, with a hard outer layer that is difficult to remove. Sorghum plants come in many different colors, including red, brown, white, and yellow, and some varieties have a sweet taste.

The crop is hardy, can tolerate heat and drought, and is adapted to a wide range of soil types. It is a relatively low-maintenance crop, requiring less water and fertilizer than many other grains, which makes it an important crop for farmers in many parts of the world.




Sorghum Varieties

 

Sorghum is a versatile crop that comes in many different varieties, each with its own unique characteristics and uses. Grain sorghum, also known as milo, is the most widely grown type and is used for food, animal feed, and biofuel production. On the other hand, sweet sorghum has a high sugar content and is used for the production of sorghum syrup, molasses, and other sweeteners. Forage sorghum, which is primarily used for animal feed, is harvested for its leaves and stalks rather than its grain. There is also broomcorn sorghum grown for the production of brooms and brushes, which are made from the plant's long, stiff fibers. Dual-purpose sorghum, as the name suggests, is grown for both grain and forage and is used to feed both humans and animals. High-tannin sorghum, on the other hand, is grown for its high tannin content, which makes it resistant to bird and insect damage.

There are many specialty varieties of sorghum that are grown for specific uses, such as ornamental purposes, traditional medicine, and cultural practices.




Climatic, soil, and water conditions

 

Sorghum is a highly adaptable crop that can grow in a variety of climatic, soil, and water conditions. However, there are certain optimal conditions for growing the crop that can maximize its yield and quality.

Climate: Sorghum is a warm-season crop that requires a long growing season with high temperatures and plenty of sunshine. It can tolerate drought, but excessive rainfall or humidity can increase the risk of diseases and reduce yield. Generally, sorghum grows well in areas with an average annual rainfall of 400–600 mm, although it can also be grown in areas with lower rainfall if there is access to irrigation.

Soil: Sorghum can grow in a wide range of soil types, from sandy to clayey, but it prefers well-drained soils with a pH between 5.5 and 7.5. It is important to have good soil fertility and adequate levels of nitrogen, phosphorus, and potassium for optimal growth and yield. The soil should also be free of weeds and other pests that can compete with sorghum for nutrients and water.

Water: Sorghum requires adequate moisture throughout its growing season, but it is also drought-tolerant and can survive in areas with limited water availability. It is important to have a reliable water source, either through rainfall or irrigation, to ensure that sorghum has enough water to grow and develop. However, overwatering can also be detrimental to sorghum, as it can lead to waterlogging and reduced yields.

Sorghum is a highly adaptable crop that can grow in a variety of climatic, soil, and water conditions. However, there are certain optimal conditions for growing sorghum that can maximize its yield and quality.




Planting Procedure

 

The planting procedure for sorghum can vary depending on factors such as climate, soil conditions, and the specific sorghum variety being grown. However, there are some general guidelines that can help ensure the successful planting and growth of sorghum.

Seed selection: Choose high-quality sorghum seeds that are adapted to your climate and soil conditions. It is important to select seeds that are disease-free and have high germination rates.

Land preparation: Prepare the land by removing any weeds, rocks, or other debris that may interfere with planting. Till the soil to a depth of 15-20 cm to loosen the soil and improve drainage.

Planting time: Sorghum should be planted during the warmer months when the soil temperature has reached at least 15°C. The specific planting time will depend on the location and climate, but generally, sorghum is planted in the spring or early summer.

Planting method: Sorghum can be planted using various methods, such as direct seeding or transplanting. Direct seeding involves planting seeds directly into the soil, while transplanting involves starting the seeds in a nursery and then transplanting the seedlings into the field.

Seed spacing: Space the seeds according to the recommended spacing for your sorghum variety. Typically, sorghum seeds are planted in rows with a spacing of 60–75 cm between rows and 10–20 cm between seeds.

Fertilization: Apply fertilizers such as nitrogen, phosphorus, and potassium as recommended based on soil test results and the specific sorghum variety being grown.

Irrigation: Provide adequate water for the seeds to germinate and establish. The amount of water required will depend on the soil moisture level and the climate.




Harvesting

The harvesting procedure for sorghum can vary depending on the specific variety, climate, and soil conditions. However, there are some general steps that can help ensure a successful and efficient harvest:

Determine maturity: Sorghum should be harvested when it reaches physiological maturity, which is when the seed head turns from green to yellow, brown, or red and the seeds become hard and difficult to dent.

Timing: The timing of the harvest will depend on the climate and variety, but generally, sorghum is harvested during the dry season, when the seeds have matured and dried out.

Equipment: Use appropriate equipment, such as a combine harvester or sickle, to harvest the sorghum.

Cutting: Use a sickle or combine harvester to cut the stalks near the base of the plant. The stalks can be cut at a height of 10-15 cm above the ground to leave some stubble for erosion control and soil conservation.

Drying: Allow the sorghum to dry in the field for a few days to a week to reduce moisture content and improve storage quality.

Threshing: Use a thresher or other equipment to remove the seeds from the seed head. Alternatively, the seed heads can be beaten with a stick to release the seeds.




References

 

CABI Crop Protection Compendium. (2010). Sorghum bicolor (sorghum) datasheet. Available at: http://www.cabi.org/cpc/datasheet/50633. [Accessed 13 April 23]. Paid subscription required.

Compendium of sorghum diseases. American Phytopathological Society Press. Available at: http://www.apsnet.org/apsstore/shopapspress/Pages/42406.aspx. Available for purchase from APS Press. Ottman, O. & Olson, O. (2009).

Espinoza, L. & Kelley, J. (Eds.) Grain sorghum production handbook. Available at: http://www.uaex.edu/publications/pdf/MP297/MP297.PDF. [Accessed 12 April 23]. Free to access. Frederikson, R. A. & Odvody, G. N. (Eds.) (2000).

Growing grain sorghum in Arizona. Available at: http://extension.arizona.edu/sites/extension.arizona.edu/files/pubs/az1489.pdf. [Accessed 13 April 25]. Free to access.




Common Pests and Diseases

Diseases

Category : Fungal

Anthracnose Colletotrichum graminicola

Symptoms
Small, circular red lesions with a distinct margin develop on leaves and stems; lesions may enalrge during humid weather conditions; plant becomes defoliated; tan spots with red margins may appear on upper parts of stems; plants may die before reaching maturity
Cause
Fungus
Comments
Disease emergence favors warm temperatures
Management
Plant resistant varieties; remove other susceptible plants e.g. Johnson grass; rotate crops; plow crop debris into soil after harvest

Charcoal rot Macrophomina phaseolina

Symptoms
Lower stalk appears shredded and dark gray; small, black fungal structures on internal parts of the stalk giving tissues a dark gray color; pith decomposes leaving only the outer stem tissue; infected plants will usually lodge
Cause
Fungus
Comments
Damage from the disease is usually greatest in fields which are subject to drought stress
Management
Plant varieties with strong stems; plant sorghum in fertile soil and avoid overcrowding unless using irrigation; use irrigation during flowering and grain-filling to reduce drought stress; rotate crop with cotton to reduce disease severity

Gray leaf spot Cercospora sorghi

Symptoms
Small red spots on leaves which enlarge to form rectangular lesions between leaf veins; lesions may coalesce to form stripes or irregular blotches
Cause
Fungus
Comments
Disease emergence is favored by periods of warm and wet weather during the growing season
Management
Disease can be controlled by planting sorghum varieties that or tolerant or resistant to the disease

Rough spot Ascochyta sorghi

Symptoms
Small, oval or elongated red spots on leaves; lesions coalesce and develop hard black fungal fruiting bodies, giving the leaves a sandpaper-like texture; rough areas may become large enough to kill entire leaf
Cause
Fungus
Comments
Fungus survives between growing seasons on crop debris
Management
Sorghum varieties with a high level of resistance should be planted in areas where the disease is problematic but the disease generally causes only minor losses when present

Smut (Covered Kernel) Sporisorium sorghi
Sporisorium spp.

Symptoms
Head replaced by brown, powdery mass of fungal spores covered by gray to brown membrane; entire head may be affected or fungus may be localized at the top, bottom or sides of the head; plants are usually or normal height
Cause
Fungi
Comments
Disease emergence favors cool dry soils
Management
Disease can be controlled by growing resistant varieties and through the application of appropriate fungicides

Zonate leaf spot Gloeocercospora sorghi

Symptoms
Concentric or zoned patches of red and purple bands separated by straw colored or tan bands on leaves; spots often occur in a semi-circular pattern along leaf margins; salmon colored spore masses may develop on lesions during periods of wet weather
Cause
Fungus
Comments
Fungus may be able to spread via infested seed; common disease of sorghum during wet weather; fungus also attacks millet speacies
Management
Losses can be reduced by rotating crop and practice of good sanitation by removing crop debris and susceptible weed species from the field
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