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Fertilizer Nitrogen Efficiency in Durum Wheat under Rainfed Mediterranean Conditions: Effect of Split Application
Author(s) -
LópezBellido Luis,
LópezBellido Rafael J.,
LópezBellido Francisco J.
Publication year - 2006
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj2005.0017
Subject(s) - agronomy , vertisol , fertilizer , sowing , leaching (pedology) , field experiment , mediterranean climate , environmental science , mathematics , biology , soil water , soil science , ecology
Efficient N fertilizer management is critical for the economic production of wheat and the long‐term protection of environmental quality. A 3‐yr field experiment on a rainfed Vertisol was designed to study the effects of N fertilizer timing on the efficiency of N in durum wheat ( Triticum turgidum L. var. durum Desf.). A single rate of 150 kg N ha −1 was used with different fractions being applied at planting, tillering, and stem elongation. A 15 N experiment was also conducted within the main experiment area, with microplots, to quantify N uptake from fertilizer and soil. Mean wheat recovery of N fertilizer ranged from 12.7% when applied at sowing to 41.6% when applied as a topdressing at the beginning of stem elongation. The mean annual contribution of soil residual N and mineralization was 167 kg N ha −1 , representing a considerable proportion of total wheat N uptake—ranging from 80.4% when N fertilizer was applied in the fall to 56.3% when it was applied at stem elongation. This would account for the poor and inconsistent response of grain yield and N efficiency indices, and for the importance of soil N in Vertisols for predicting wheat N fertilizer requirements, due to the carryover effect. It is recommended that N fertilizer be applied mainly as a topdressing in durum wheat, between tillering and stem elongation, to enhance crop N use efficiency (NUE) and reduce losses through leaching and runoff.