Modeling Nitrogen Use Efficiency Under Changing Climate

Abstract

Nitrogen is the most limiting element in the production of cereal crops after water hence leads plant nutrition. Since, nitrogen uptake and supply directly depends upon soil physical conditions, climate and plant genetic features, so N requirement could be varied by place to place. Crop simulation models can be complementary tools in field experiments to develop innovative crop management systems under continuous varying nitrogen regime. Data regarding total nitrogen, nitrogen uptake efficiency, nitrogen utilization efficiency and nitrogen utilization efficiency, drymatter accumulation at three phenological stages (Three leaf, Anthesis and Maturity), and yield parameters (Number of tillers, Biological yield, Thousand grain weight, Grain yield and Harvest index) were recorded. The present study revealed that different nitrogen rates and application methods have significant impact upon crop growth and development. Wheat crop responded well to nitrogen fertilizer. Maximum grain yield obtained for N100 when nitrogen was applied as split dose. Similarly, genotypes responded significantly to nitrogen fertilizers for grain production. Genotype NARC-2009 performed well under different nitrogen regime of rainfed zone of pothwar. APSIM model was parameterized using different agronomic parameters (days after sowing, biomass total nitrogen, root total nitrogen, grain yield and grain total nitrogen). The modeled nitrogen was satisfactory compared to observed nitrogen. The analysis of the modeling results depicted the strong dependency of the mineral nitrogen content upon plant nitrogen uptake and growth. By concluding APSIM model performed well under rainfed conditions of pothwar for modeling nitrogen use efficiency. Modeling approaches should be adopted by farmers and policy makers to get maximum crop production and eliminate extra nitrogen losses.