Nitrogen Management and Uptake by Corn on No‐Till and Ridge‐Till Claypan Soil

Abstract

Core Ideas Seasonal corn N uptake was greater with ridge‐till than with no‐till. Increasing N fertilizer rate generally increased N uptake. Nitrogen uptake at R4 was greater with banded applications than broadcast in no‐till. Increasing N uptake increased yield, primarily by increasing kernels per ear. Information on N management is limited regarding N uptake and recovery by corn (Zea mays L.) grown on claypan soils in the eastern Great Plains, especially in conservation tillage systems. The objective of this study was to examine the effect of fertilizer N rate (0, 34, 67, 101, and 134 kg ha‐1) applied by surface broadcast, surface band (dribble), and subsurface band (knife) placement methods on N uptake by corn grown in no‐till and ridge‐till systems on a claypan soil. Ridge‐till consistently increased corn N uptake compared with no‐till by 53% early to 20% later during the growing season. Maximum N uptake rate was earlier in the season and greater with ridge‐till than with no‐till, perhaps helping to contribute to increased corn yields. Early in the season, corn N uptake was increased with low N fertilization rates, but not at higher rates. However, as the season progressed, N uptake increased with all rates. Even though the effect of N fertilizer placement on corn N uptake was not consistent during the entire season, by the R4 growth stage, placement did not affect N uptake in ridge‐till but was nearly 20% greater with banded (dribble and knife) applications than with broadcasting in no‐till. At low N rates, knife placement increased N uptake at R4, likely because of improved apparent N recovery, but was unaffected by placement at greater N rates. Improving total N uptake increased relative yield primarily by increasing kernels per ear, with lesser effects due to kernel weight and ears per plant.