Impact of Banded Potassium on Crop Yield and Soil Potassium in Ridge‐Till Planting

Abstract

Adequate application of fertilizer K has been identified as a key management practice needed to achieve optimum production in a ridge‐till planting system. However, the impact of K fertilization frequency has not been documented. Additionally, banded application of K also raises questions about the correct procedure to be followed for collection of soil samples. This study was conducted in the fields of three farmers who used the ridge‐till planting system for corn (Zea mays L.) and soybean (Glycine max L.) grown in rotation. Potassium was applied in a subsurface band in the center of existing ridges in the fall of Year 1 before corn and Year 2 before soybean at rates of 0, 18.5, 37.0, 55.5, and 74.0 kg ha−1 To measure the effect of residual K on soybean yield, the rates were doubled and applied only once (before Year 1). Grain yield of both corn and soybean at all sites was not affected by K application. Potassium uptake by young corn plants was increased by K rate, but uptake was not related to yield. Potassium use had no significant effect on K concentration in the most recently matured soybean trifoliate leaves sampled at early bloom. At two sites, banded K produced changes in soil test K to a depth of 15.0 cm at a distance to 15.0 cm from the row.