Potassium availability often decreases with depth but may be extremely important to meet late-season K requirements. Effects of Potassium on Maturity, Quality, and Disease Resistance. A large visual growth-response due to fertilizer K additions usually indicates a maturity response. Corn planted in cool soils may show a visual growth-response while plantings made in warmer soils show little or no response to starter applications of fertilizer. Where K is extremely deficient and corn shows severe K deficiency symptoms, silking may be delayed by as much as 2 weeks.
Balanced fertility promotes early development of corn.
After silking, plants well supplied with K have shown delayed maturity, adding a few days to the grain by production time. A summary of the research indicates that N and P tend to reduce grain moisture at harvest while K, over a wide range of soil fertility levels, either has no influence or slightly increases grain moisture. Much data are available to show that unbalanced fertility due to a deficient nutrient leads to undesirable plant characteristics that may reduce yields. High stalk breakage can result in greatly reduced yields at harvest on low K soils without K applications. Potassium is very important in decreasing lodging, especially when harvest is delayed for a month or more by inclement weather.