Effects of Water and Fertilizer Management on Yield of Spring Wheat and Fertility Characteristics in Rhizosphere Soil

Using a split-split plot design, we studied the effects of irrigation quota (4 500 m³·hm^-2, 6 000 m³·hm^-2 and 7 500 m³·hm^-2), green manure (green manure and no green manure) and chemical fertilizer (chemical fertilizer and no chemical fertilizer) on yield of spring wheat and fertility characteristics in rhizosphere soil, and developed a water and fertilizer management model for high yield of strip spring wheat in irrigated desert soil region. The results showed that spring wheat yield increased significantly with increasing irrigation quota, the increasing extent of 6 000 m³·hm^-2 and 7 500 m³·hm^-2 were 7.73% and 9.99% compared with 4 500 m³·hm^-2, respectively; the yield increasing extent with chemical fertilizer was 132% compared with no chemical fertilizer. The interaction between green manure and chemical fertilizer on spring wheat yield was significant; the highest yield of 2 639 kg·hm^-2 was achieved under the interaction between green manure and chemical fertilizer, and the lowest yield of 987 kg·hm^-2 was achieved under the interaction between green manure and no chemical fertilizer, with the difference of 167%. Available N and K in rhizosphere soil decreased significantly with increasing irrigation quota, while water content and soil pH indicated a significant increasing trend with increasing irrigation quota. Green manure increased soil available N, organic matter and water content and decreased soil pH significantly. Chemical fertilizer increased soil available N and P and decreased soil available K, water content and pH significantly. The interaction between irrigation quota and chemical fertilizer on soil available N was significant; the highest available N content was observed under 4 500 m³·hm^-2 plus chemical fertilizer, and the lowest content was observed under 7 500 m³·hm^-2 plus no chemical fertilizer, with the difference of 80.6%. The optimal water and fertilizer management model for high yield of spring wheat in irrigated desert soil region was with 6 000 m³·hm^-2 of irrigation quota and green manure combined with chemical fertilizer; the corresponding spring wheat yield was 2 667 kg·hm^-2, and the available N, P, K, organic matter, water content and pH in rhizosphere soil were 106 mg·kg^-1, 34.7 mg·kg^-1, 93.6 mg·kg^-1, 23.3 g·kg^-1, 11.5% and 8.29, respectively.