By Andi Anderson
The 2024 growing season in Ohio has seen irregular rainfall, keeping fields wet in many northwestern counties and delaying planting until late May and early June.
Despite varied weather conditions, above-average temperatures and accelerated growing degree unit (GDU) accumulation have been consistent across the state. This raises concerns about the impact of high temperatures on corn and soybean crops.
Warm weather accelerates corn growth, with optimal daytime temperatures between 77°F and 91°F. Growth slows when temperatures exceed 95°F, especially if soil moisture is lacking. Leaf rolling is the first sign of drought stress in corn.
Severe drought can cause corn tissue to turn gray, shorten plant height, and yellow or brown lower leaves. The extent of yield loss depends on the growth stage and the duration of plant wilting.
Early drought impacts nodal root development in corn, leading to "floppy" or "rootless" corn between V1 and V5 stages. During V6-V8 stages, severe drought can result in slender ears with fewer rows.
Nutrient deficiencies, particularly in mobile nutrients like nitrogen and potassium, can appear on lower leaves during prolonged drought. Yield-critical functions during reproductive stages, such as pollination and ear filling, require ample moisture, making drought during these stages particularly harmful.
Soybeans, like corn, experience less yield impact from early vegetative drought compared to dry weather during reproductive stages. Drought responses in soybeans include decreased leaf size, leaf flipping to conserve water, and leaf clamping. Soil temperatures above 90°F for prolonged periods can reduce nodulation and nitrogen fixation, although short-lived water deficits may allow recovery. Severe drought can cause premature flowering, reduced flowering windows, and increased flower and pod abortion, with the greatest yield impact occurring between growth stages R4 and R6.
As forecasts predict continued high temperatures and limited rainfall, farmers may consider applying foliar fertilizers, plant growth hormones, amino acids, and other biostimulants to temporarily boost crop health. However, timely rainfall remains the best remedy for hot, droughty conditions.
Ohio farmers face significant challenges due to irregular rainfall and high temperatures, which affect the growth and yield of corn and soybean crops. Understanding and mitigating these impacts is crucial for maintaining crop health and productivity.
Photo Credit: gettyimages-zhuda
Categories: Ohio, Weather