Effects of Water and Nitrogen Management on Yield and 15N‐Depleted Fertilizer Use Efficiency of Irrigated Corn

Abstract

The objective of this experiment was to evaluate the effects of irrigation sequence and of time and rate of nitrogen application on the dry matter production and fertilizer use efficiency of irrigated corn (Zea mays L.), grown on a representative fine‐textured soil of eastern Nebraska, and to monitor the movement of fertilizer N in this soil. During 1974–1976, 15N‐depleted ammonium sulfate was banded at rates of 112, 168, or 224 kg N/ha at planting or sidedressed at the eight‐leaf growth stage. No N was applied in 1977–1979. In 1974–1977, irrigation applications of 5, 7.5, or 10 cm of water were made at 2‐, 3‐, or 4‐week intervals, respectively, until a total of 30 cm had been applied. The plots were uniformly irrigated in 1978–1979.Grain yield and N uptake in 1974–1976 were not influenced by time of N application, and were highest with light, frequent irrigation. From 1977–1978, yield increased with previous N rate in response to residual mineral N in the soil. During both treatment and residual years, fertilizer N recovery in the grain was greater with sidedressing and increased with N rate. Heavier, infrequent irrigation decreased tracer N recovery in 1974–1976. Maximum fertilizer use efficiency was obtained with the low N rate, applied as a sidedressing, and with light, frequent irrigation.

Current Nitrogen Management Status and Measures to Improve the Intensive Wheat–Maize System in China

“…Therefore, more N fertilizer (around 60-70% of the total N fertilizer applied) should be applied during the fastest growing stages of the crop to achieve synchrony between the N supply and crop demand. This is consistent with early observations that N fertilizer should be applied close to the peak N uptake to increase grain yield and NUE and decrease the opportunity for soil N losses (Russelle et al 1981;Welch et al 1971).…”

“…Nitrogen application in excess of crop N demand at the early growth stage increases the potential for nitrate-N leaching and results in excessive crop growth that is more susceptible to disease infection and wheat lodging. Applying N fertilizer near to the time it is needed by the crop increases crop grain yield and improves NUE (Russelle et al 1981;Welch et al 1971). Results from Iowa (Sanchez and Blackmer 1988) indicate that 50-64% of fall-applied N is lost from the upper 1.5 m of soil by processes other than crop uptake.…”

INNOVATIVE15N MICROPLOT RESEARCH TECHNIQUES TO STUDY NITROGEN USE EFFICIENCY UNDER DIFFERENT ECOSYSTEMS

“…The potential to design experiments using depleted 15 N are illustrated in studies by Broadbent (1980), Patrick et al (1984), Porter (1995), Russelle et al (1981), and others. An example where depleted 15 N was used is that by Porter (1995), where he evaluated N-fertilizer carryover, leaching, and uptake under continuous irrigated corn (Zea mays L.) on a Weld silty clay loam (fine, montmorillonitic, mesic Aridic Paleustoll) near Akron, Colorado.…”

“…In an irrigated study with corn, Russelle et al (1981) had the objective of determining N fertilizer and water management practices that would maintain high yields on fine-textured soils of eastern Nebraska without adversely affecting the environment. During 1974During to 1976 N-depleted ammonium sulfate was banded at rates of 112, 168, or 224 kg N ha Ϫ1 at planting or sidedressed at the eight-leaf growth stage.…”

Furrow Irr Igation and N Management Strategies to Protect Water Quality

“…In Idaho and elsewhere, residual and recently mineralized NO3-N can be leached by late-season irrigations (Wright et al, 1998) or an early-season irrigation just before planting (Meek et al 1995;Robbins and Carter, 1980). Irrigation must be well managed to efficiently use N fertilizer applied at nominal, economic rates (Keeney, 1982;Robbins and Carter, 1980;Russelle et al, 1981). In western Idaho, many producers apply large amounts of N to onion (Allium cepa) to compensate for leaching and denitrification losses from excessive irrigation (B.D.…”