[Effect of long-term fertilization on winter wheat yield from the dry land under different precipitation patterns]

Based on 30 years long-term fertilization experiment on the semiarid Loess Plateau in China, we studied the effect of different fertilizer treatments on the winter wheat yield, fertilizer contribution rate (FCR) and precipitation use efficiency (PUE) in different precipitation years (drought, normal and wet years). The result showed that the wheat yield, FCR and PUE were significantly higher in nitrogen + phosphorus (NP) and nitrogen + phosphorus +potassium (NPK) treatments than in control (CK) and phosphorus (P) treatments when winter wheat was planted for 30 consecutive years. The wheat yield, FCR and PUE in NPK treatment were highest, with values of 3480 kg·hm^-2, 61.45 kg·kg^-1 and 6.13 kg·mm^-1·hm^-2, respectively, and those in the wet years were higher than in drought and normal years. The stepwise regression analysis showed that wheat yield was mainly influenced by the amount of nitrogen, phosphorus input and precipitation during fallow period and wintering period. Accordingly, increasing nitrogen and phosphorus input accompanying with potassium and water conservation practices during the fallow period could improve the wheat yield on the semiarid Loess Plateau in China.