Grain sorghum producers can receive improved prices, reduce field losses and increase harvest efficiency if their sorghum crop has more uniform moisture levels that meet moisture specifications at harvest.
Several factors can cause uneven moisture in sorghum at harvest including different plant emergence dates in the same field, drought conditions followed by rain, iron chlorotic spots in the field delay maturity, different soil types, poor plant stands with late tillers, and weeds.
Harvest of grain sorghum can be made more efficient by the use of harvest aids. Application timing of the harvest aids is critical, so as not to reduce yield and grain quality. Sorghum becomes mature and is ready for harvest at about 115 days after planting. Most sorghum varieties reach 50 percent bloom in 65 to 75 days after planting, and then another 45 days are required for the grain to mature. Harvest aids should be applied once the grain reaches physiological maturity and the average grain moisture drops below 30 percent.
An important note to consider, treat only those acres that can be harvested within 10 days to two weeks after application.
Grain sorghum is mature when a black layer appears on the sorghum kernels. Look for a black spot or black layer at the base of the kernel. Grain moisture testers can also be used to determine when the grain moisture falls below 30 percent.
Only two products are labeled for use as harvest aids: sodium chlorate (containing a fire retardant) and glyphosate. For good results, good spray coverage is needed with both products, which can be achieved with eight to 10 gallons per acre of solution by ground or three to 5 gpa by air. Sodium chlorate may be applied up to six pounds per acre, and for good desiccation with this product the weather must be hot and dry. Glyphosate, an herbicide that kills the plant, can be used at rates up to 2 quarts per acre. The rates needed depend on the sorghum variety and condition of the plant. To improve effectiveness, include a sprayable grade of ammonium sulfate at a rate of 17 pounds/100 gallons of water or a prepackaged sulfate formulation. There is a seven-day waiting interval between application and harvest, and the crop is usually ready seven to 10 days after application. An added bonus, glyphosate also controls, rhizome Johnsongrass, silverleaf nightshade, morning glory and most other perennial weeds.
Crop lodging is one concern that growers have when using harvest aids. If the plant is healthy, there is usually no need to worry about crop lodging after harvest aid application. To avoid any premature lodging, inspect the field before application. Look for stalk degradation from diseases such as charcoal rot, which can cause premature lodging during natural dry down or after harvest aids are applied. If the stalk is not healthy, it will generally fall, whether or not it has been treated.
As with all farm chemicals, always read and follow label directions carefully before applying the product.
Any references made to commercial products or trade names were made solely for educational purposes with the understanding that no endorsement nor discrimination is implied by the Texas AgriLife Extension Service or its agents.
Jeffrey Stapper is the Agricultural and Natural Resources Agent for Nueces County. Readers may contact him at (361) 767-5217.