Nitrogen availability as a tool for increasing attainable wheat yield in environments with water restrictions

ABELEDO LG; SAVIN R; SLAFER GA

Lérida, España

Workshop; 15th Nitrogen Workshop – Toward a better efficiency in N use; 2007

RUENA (Red para el uso eficiente del N en la agricultura)

Water deficit is an important constraint of wheat yield under Mediterranean environments. In addition, low N availabilities could reduce yield under water stressed conditions. The aim of the work was to analyze, using the CERES-Wheat crop simulation model, if N availability modifies the gap between potential and attainable yield. The study was carried out considering a weather database of 17 years for Agramunt (NE Spain). Potential yield ranged between 3.5 and 8.1 Mg ha-1. Variations in potential yield were mainly explained by the level of incident radiation during the pre-anthesis period. Variations between years in attainable yields were explained by rain. The proportion of the yield gap ascribed to N availability depended on the year. For years of high potential yield the main restriction for growth was water availability and increasing N availability slightly reduced the gap. In relatively rainy years, characterized by low yield potential and less severe water stresses, N management (up to 150 kgN ha-1 at sowing) constituted a way for reducing yield gap.