Leverage environmental assets to maximize grain sorghum yield potential.
Agronomy Bulletin 59 ─ Grain Sorghum Production
Grain sorghum is an attractive crop because of its water-use and nutrient efficiency. Before planting grain sorghum, consider the various environmental aspects and agronomic factors essential for high yield potential.
Factors to Consider
- Field selection
- Row width
- Planting dates
- Fertility needs
- Soil conditions
- Weed control
- Planting depth
- Water availability
- Gauge soil conditions. Because of the small size of grain sorghum seeds, placement and seed-to-soil contact are critical. Grain sorghum requires a well-drained seedbed with good soil tilth. Soil temperature should be higher than 65 F at planting — 70 F or higher is preferred — to support rapid germination and uniform emergence. Early maturing hybrids can be planted as late as early July in adapted areas. Later planting exposes grain sorghum to detrimental fall frost damage before maturity.
- Plant at correct depth. Grain sorghum seeds should be planted at a 11/2-inch depth, but they can be planted as deep as 2 inches to ensure 3/4 to 1 inch of soil moisture. In sandy soils, the depth should be closer to 1 inch. Also, be vigilant of row width. Consistently, 30-inch rows produce higher yields than rows both narrower and wider.1
- Determine fertility needs. Grain sorghum’s large fibrous root system efficiently utilizes nutrients from the soil. However, supplemental nitrogen (N) may be needed to meet yield goals. To determine the amount of fertilizer needed, first conduct a soil test. Fertilizer needs depend on the results and yield expectations. A standard rule is 11/4 pounds of N will produce a bushel of grain sorghum.
- Control weeds. Grain sorghum should be planted into a field with minimal weed pressure. Heavy infestations of grassy weeds in the two weeks following germination may reduce yield by up to 20 percent. Preplant burndown programs kill winter vegetation prior to planting. To fight preemergence grasses, consider an acid amide family herbicide combined with atrazine. Concep® III seed safener allows for use of preemergence herbicides such as Dual® and Bicep®. As always, read, understand and follow label directions.
- Analyze water availability. An extensive root system also increases the crop’s drought tolerance. Seasonal water need is approximately 18 inches to 22 inches. If your field has less than 20 inches of moisture available, consider reducing your planting rate to 32,000 seeds per acre. On average, this planting can produce around 60 bushels per acre. If you have roughly 32 inches of moisture available, plant 100,000 seeds per acre to aim for higher production of approximately 130 bushels per acre or more.1
- Irrigate conservatively. Generally, only one or two irrigation applications (4 to 6 inches water per application) will compensate if the minimum 18-inch total will not be met. Preplant irrigation generally is not recommended.
With effective management, grain sorghum can be a good option for producers looking for a nutrient-efficient, drought-tolerant crop or a fully irrigated crop with reduced production costs. For more information, contact your local Mycogen Seeds customer agronomist or trusted agronomic adviser.