Tips To Prepare For A Successful Corn Harvest
DR. ERICK LARSON
MISSISSIPPI STATE, MISSISSIPPI
Corn harvest should continue to ramp up as grain dries down to lower moisture content. Thus far we have generally had good weather for grain drydown and few storms or wind which could potentially complicate harvest. Understanding how weather and other factors affect grain drying, potential harvest losses, moisture dockage and potential aflatoxin issues can greatly help improve your harvest efficiency and success.
Corn grain maturity, drydown and harvest aids – When corn reaches maturity a “black layer” forms at the kernel base when hard starch accumulation is complete. This black layer is an abscission layer that effectively cuts off moisture transfer and all physiological activity from the plant. Thus, grain drying rate is essentially completely dependent upon environmental conditions, rather than plant health or disposition. Furthermore, since corn is an annual plant, the vegetation will naturally senescence or die after maturity, particularly when temperatures are hot and/or soil moisture is limited. Consequently, using a harvest aid will have little or no effect on grain drying, since the black layer halts moisture flow to the grain, and the plants are already naturally dying.
Grain drying rate in the field – Climate basically dictates corn grain drying in the field. Fortunately, we are normally blessed with plenty of heat and dry weather during August and September, so our corn drying rates are usually considerably greater than states further north, including the Corn Belt. However, when rainfall persists, along with cloudy days, high humidity and cool temperatures, grain drying will slow considerably or be suspended. Mississippi corn normally dries at an average rate of 0.6% per day from physiological maturity (when grain moisture is around 30%) down to 15% moisture. However, this drying rate will inherently be faster when grain moisture is high, and then scales back as it drops into the teens, when the disparity between grain moisture and the environment diminish. Accordingly, you may see grain moisture dry as much as 0.8 or 0.9% per day given sunny, hot weather as grain approaches 20% moisture.
Factors that affect harvest efficiency and losses – The best time to begin corn harvest may vary considerably, primarily depending upon how long it takes to harvest your crop. This will depend on how many acres you have, relative to your harvesting capability, including combine, trucking, and storage capacities. These factors, along with the other crops you grow on your farm, determine the potential harvest duration and the relative risk associated with harvest losses, delays or other complications. Those potential risks include various types of stalk lodging and/or grain quality deterioration, which can result from stormy weather, insect pest damage, and late‐season weed growth. The most significant weather-related threat to Midsouth corn is likely storms containing high winds promoting stalk lodging. One dropped ear per 100 feet of row or two corn kernels per square foot or equals about 1 bushel per acre yield loss. The bottom line is that the longer corn stays in the field, the greater the likelihood of substantial field losses and complications.
Grain drying rate in the field – Climate basically dictates corn grain drying in the field. Fortunately, we are normally blessed with plenty of heat and dry weather during August and September, so our corn drying rates are usually considerably greater than states further north, including the Corn Belt. However, when rainfall persists, along with cloudy days, high humidity and cool temperatures, grain drying will slow considerably or be suspended. Mississippi corn normally dries at an average rate of 0.6% per day from physiological maturity (when grain moisture is around 30%) down to 15% moisture. However, this drying rate will inherently be faster when grain moisture is high, and then scales back as it drops into the teens, when the disparity between grain moisture and the environment diminish. Accordingly, you may see grain moisture dry as much as 0.8 or 0.9% per day given sunny, hot weather as grain approaches 20% moisture.
Factors that affect harvest efficiency and losses – The best time to begin corn harvest may vary considerably, primarily depending upon how long it takes to harvest your crop. This will depend on how many acres you have, relative to your harvesting capability, including combine, trucking, and storage capacities. These factors, along with the other crops you grow on your farm, determine the potential harvest duration and the relative risk associated with harvest losses, delays or other complications. Those potential risks include various types of stalk lodging and/or grain quality deterioration, which can result from stormy weather, insect pest damage, and late‐season weed growth. The most significant weather-related threat to Midsouth corn is likely storms containing high winds promoting stalk lodging. One dropped ear per 100 feet of row or two corn kernels per square foot or equals about 1 bushel per acre yield loss. The bottom line is that the longer corn stays in the field, the greater the likelihood of substantial field losses and complications. ∆
DR. ERICK LARSON
MISSISSIPPI STATE UNIVERSITY