Abstract: 【Objective】Water and fertilisation are the main two factors limiting wheat production in arid and semiarid regions of the Loess Plateau. The effects of precipitation patterns and phosphorus nutrition levels on wheat yield under long-term fertilizer field experiment were studied. The result will provide a theoretical basis for improving wheat yield with a reasonable phosphorus level with different precipitation patterns in the semiarid regions.【Method】Growth years precipitation were divided into dry years, normal years and wet years based on 30 years long-term fertilizer field experiment on the semiarid Loess Plateau in China. Effects of precipitation patterns and phosphorus nutrition levels on the winter wheat yield, yield component and phosphorus contribution rate (PCR) were deeply studied on the semiarid Loess Plateau.【Result】Wheat yield, 1000-grain weight, grains per spike and spike numbers in the dry years were lower than the normal years, higher in the wet years than the normal years. pCR in the dry years was higher than the normal years, lower in the wet years than the normal years. Wheat yield, 1000-grain weight and grains per spike in the dry, normal, wet and 30 years planting showed a trend of increase first and fall later with the adding of phosphorus. Spike numbers were increased first and fall later in the dry years, presented a rise perpendicularly in the normal years, wet years and 30 years planting. PCR was increased first and fall later in the dry years, presented a rise perpendicularly in the normal years, linear decrease in the wet years. The correlation coefficient between the yield and yield components showed that different precipitation patterns mainly through affecting the spike numbers to influence the yield. The partial regression coefficient among spike numbers and dry, normal, wet years and 30 years planting was 0.713, 0.294, 0.692 and 0.643, respectively.【Conclusion】Phosphorus nutrition levels and precipitation patterns could significantly impact the wheat yield. The yield in the 125-137 kg·hm^-2 phosphorus treatment was the best in different precipitation patterns. The yield in the 131 kg·hm^-2 phosphorus treatment was the best with the 30 years continuous planting. Precipitation patterns and phosphorus nutrition levels mainly through regulating the spike numbers of wheat yield components to influence the yields.

Key words: winter wheat, precipitation patterns, phosphate fertilizer treatment, phosphorus contribution rate, yield and yield component