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Nitrogen uptake by corn from fertilizer and irrigation sources
Abstract
The efficient management of both water and nitrogen (N) is critical to reducing the accumulation of nitrate-nitrogen (NO$\sb3$-N) in ground water under much of the Central Platte River Valley of Nebraska. Overly optimistic yield goals and the failure to account for residual inorganic soil N, N mineralization, and N supplied by irrigation water contribute to overfertilization and the potential for nitrate leaching. In order to evaluate the N uptake efficiency of NO$\sb3\sp-$ applied with irrigation water and to determine the fate of fertilizer and irrigation applied N, a 2-year study on irrigated corn (Zea mays L.) was initiated in Hall County, Nebraska. Microplots were established to accommodate 4 fertilizer N rates (0, 50, 100, and 150 kg/ha) receiving irrigation water containing 3 levels of NO$\sb3$-N (0, 10, 20 mg/L). For each given treatment, stable isotope $\sp{15}$N was applied as a tracer in either the fertilizer or water. Grain yields in 1982 were not influenced by fertilizer N rates or irrigation NO$\sb3$-N concentrations. Stover yield and percent N in both grain and stover were positively correlated to fertilizer N rate. The lack of grain yield response is attributed to the relatively high level of residual soil N and the high amount of mineralized N. During the second year, a more typical N response was obtained with the maximum grain yield reached at the 100 kg N/ha fertilizer rate. Under the conditions of this study, the majority of N supplied with irrigation water was applied after tasseling which was too late to affect grain yields. For both years, the uptake efficiency of the sidedressed N fertilizer was not affected by the application of N in the irrigation water. The N uptake efficiency of the NO$\sb3\sp-$ applied in the irrigation water was negatively correlated to the amount of sidedressed fertilizer N. Second year recovery of residual $\sp{15}$N applied in the irrigation water was greater at the highest rates of fertilizer and irrigation N. Both growing seasons ended with substantial amounts of residual NO$\sb3\sp-$ in the soil derived from mineralization. Production practices must be developed which will make greater use of this late season mineralized N.
Subject Area
Agronomy
Recommended Citation
Francis, Dennis Dean, "Nitrogen uptake by corn from fertilizer and irrigation sources" (1989). ETD collection for University of Nebraska-Lincoln. AAI8925238.
https://digitalcommons.unl.edu/dissertations/AAI8925238