Maize plant nitrogen uptake dynamics at limited irrigation water and nitrogen.

ABSTRACT

Knowledge of the dynamics of plant nitrogen (N) uptake at varying irrigation water levels is critical for strategizing increased N recovery efficiency (NRE), water use efficiency (WUE), and maize yield. The N dynamics were studied under various irrigation regimes to evaluate NRE, WUE, and maize yield. A pot experiment was conducted using three irrigation water regimes (50, 75, and 100% field capacity (FC)) and four N fertilizer rates (0, 1.6, 3.2, and 4.8 g pot-1) applied with two fertilizer application methods including foliar and soil applications. The highest plant growth and grain yields were achieved by application of 4.8 g N pot-1 with 100% FC. Contrarily, the maximum WUE (7.0 g L-1) was observed by the lowest irrigation water (50% FC) with the highest N fertilizer rates (4.8 g pot-1). Nitrogen concentration in the stem and grain was linearly increased by increasing N fertilizer rates with irrigation water. However, in the root, N concentration was decreased when the crop was supplied with 100% FC. In plant, maximum N uptake (6.5 mg g-1) was observed when 4.8 g N pot-1 was applied with 100% FC. Nitrogen recovery efficiency was increased by increasing N rate up to 3.2 g pot-1 with 100% FC. Therefore, for achieving maximum WUE and NRE, the highest water and N applications, respectively, are not necessary.