Quantifying the Impact of Climate, Irrigation and Nitrogen on Winter Wheat Yield in Guanzhong Plain of Northwest China
2015
Ji Jianmei | Cai Huanjie | He Jianqiang | Wang Jian
Wheat (Triticum durum) yields have increased significantly because of the increasing higher irrigation and fertilizer inputs since the last half of 20th century. With varying climate and rising population, increasing focus is being given to enhancing resource use efficiency while increasing yields. This study utilized the CERES (Crop Estimation through Resource and Environment Synthesis) - Wheat model to analyse the impact of irrigation, nitrogen (N) and climate on wheat yield, using 58-year climate data. Analyses were conducted using four assumed scenarios with step-by-step method. Results showed that the optimum irrigation and nitrogen ranges were not uncertain when taking into account a single factor. When considering both irrigation and nitrogen, the impact of irrigation on simulated grain yield was greater than that of nitrogen, which was similar to the results obtained from the experiments. The average variation in grain yield was attributed to irrigation (46.8%), nitrogen (5.5%) and climate (2.4%). Besides, relative humidity and maximum temperature were consistently and significantly correlated with grain yield under all conditions, while precipitation had a significant correlation with grain yield when no irrigation or N was applied, or one of them was applied. However, solar radiation was significantly correlated with grain yield when both irrigation and N were available.
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