By Jeremiah Butler, Agricen
Early in the summer of 2023, widespread nutrient deficiencies were observed in the Corn Belt, particularly potassium (K) deficiency in corn. Due in large part to drier-than-average early season growing conditions, abiotic stress—or stress from environmental conditions—was more prevalent, impacting crop physiological development and reducing nutrient uptake during a critical phase.
Beginning in mid-June, a number of crop consultants were reporting an interesting phenomenon. Corn fields treated with a foliar application of TERRAMAR in the V3-V7 growth stage visually appeared to be healthier and were not exhibiting the same level of K deficiency symptoms as untreated corn.
As a result of these observations, trials were conducted on later-planted corn in Minnesota and Michigan, and on a soybean field in Indiana to evaluate the impact of a V4 application of TERRAMAR on nutrient uptake and abiotic stress reduction. Corn nutrient demand significantly increases after the V4 window to produce a healthy, high-yielding crop.
In the Minnesota trial, a foliar application of TERRAMAR (1 quart/acre) was made at V4, followed by rigorous tissue sampling to determine nutrient uptake levels of treated versus untreated plants. A total of 135 tissue samples were taken at the V9 growth stage (10 days after application) hourly over a 12-hour period (7 am to 7 pm). In addition, leaf surface temperature readings of treated and untreated plants were taken to evaluate canopy temperatures. Higher ambient air temperatures during the trial period were an indication that the corn crop was experiencing moderate heat stress.
Compared to the untreated corn, TERRAMAR increased the uptake of the majority of nutrients into the corn leaf tissue (Fig. 1). Potassium uptake was particularly notable, showing a 38% increase compared to the untreated corn.