Corn growth and yield responses to starter fertilizers in conservation-tillage systems

Abstract

The purpose of this 3-year field study, which was conducted on a Norfolk sandy loam (Typic Paleudult), was to determine if initial growth and final yield of corn ( Zea mays L.) grown in conservation-tillage systems (chisel plow and strip tillage) could be improved by the application of starter fertilizer. Treatments consisted of six starter fertilizer combinations (0-0-0, 24-0-0, 0-26-0, 0-0-66, 24-26-0, 24-26-66 kg ha −1 of NPK, respectively). The initial soil pH was 6.0 and soil test P and K levels were high. Side-dress N (224 kg ha −1) was applied 6 weeks after planting. The corn was planted with an in-row subsoiler planting unit and the fertilizers were placed in the subsoil tracks. Plant heights 6 weeks after planting were greater with than without starters, but this difference was primarily due to N. Concentrations of N, P and K in the young plant tissue, regardless of tillage, were increased when these nutrients were included in the starter combinations. Nitrogen concentrations in the ear leaf were not affected by treatments. Leaf K was higher with than without K-containing starters each year, but leaf P was higher with than without P-containing starters in only 1 year. Grain yields were increased by the N-containing starter fertilizers each year. The yield increases were more closely related to differences in early-season plant growth than to differences in nutrient concentrations in plant and leaf tissue. In 2 years, the NPK combination resulted in highest yields, but in the other year, NP was adequate. Higher grain yields were obtained with the strip-tillage than chisel-plow system in 2 of the 3 years.