Soil Water Use Characteristics of Spring Wheat with Multiple-Cropping Green Manure and Nitrogen Reduction in Northwest Irrigated Areas
[Objective]The aim of this study was to explore the effects of multiple-cropping green manure and reduced nitrogen(N)application on water use characteristics of spring wheat in northwest irrigated areas,so as to provide a theoretical basis for optimizing the efficient use of water resources in spring wheat production.[Method]A split-zone design was adopted,with two cropping patterns of multiple-cropping green manure(W-G)and post-wheat fallow(W)in the main zone,three N fertilizer levels in the sub-plot:conventional N fertilizer application(180 kg·hm-2,N3),N fertilizer reduction of 15％(N2,153 kg·hm-2),and N fertilizer reduction of 30％(N1,126 kg·hm-2).The effects of multiple-cropping of green manure and nitrogen reduction on yield,water consumption and water use efficiency of spring wheat were studied from 2020 to 2021.[Result]The multiple-cropping green manure combined with moderate reduction of nitrogen fertilizer increased the pre-sowing soil water storage of spring wheat,and W-G increased the pre-sowing soil water storage of spring wheat by 11.5％to 13.5％compared with W pattern,while the multiple-cropping green manure combined with N reduction of 15％(W-GN2)and multiple-cropping green manure combined with N fertilizer reduction of 30％(W-GN1)increased the pre-sowing soil water storage of spring wheat compared to control post-wheat fallow combined with conventional N fertilizer application(W-N3)by 12.1％to 20.2％and 15.2％to 16.6％,respectively.W-G reduced water consumption of spring wheat by 12.6％to 13.7％compared with W-GN1,and W-GN2 reduced water consumption of spring wheat by 15％compared to W-N2 and W-N3,respectively.W-G effectively harmonized the water demand characteristics of spring wheat before and after the reproductive period by reducing the evapotranspiration modulus coefficient of spring wheat at the early stage of nodulation and filling,and increasing the evapotranspiration modulus coefficient of pre-sowing to jointing and early-filling to maturity(the proportion of water consumption of the two stages to the total water consumption of the whole reproductive period was 60.5％to 64.1％).Finally,the synchronization of water supply and demand during the growth and development of spring wheat was enhanced.W-G had the advantage of yield increase,with 13.5％to 14.1％under W pattern.W-GN2 and W-N3 had yield increases of 16.7％to 18.4％and 13.6％to 14.6％under W-N2 and W-N3,respectively.Thus,W-G improved water use efficiency by 29.4％to 31.0％compared with the W pattern,and among the multiple-cropping green manure,W-GN2 improved water use efficiency by a greater extent than W-N2 and W-N3 by 44.2％to 46.8％and 39.1％to 43.5％,respectively,and W-GN1 and W-GN3 by 36.2％to 50.7％and 9.1％to 17.0％,respectively.[Conclusion]The multiple-cropping green manure combined with 15％N fertilizer reduction(i.e.,153 kg·hm-2 of N fertilizer)improved spring wheat yield and water use efficiency compared with conventional water and N fertilizer management,and could be recommended as a production technique for efficient water use in spring wheat in dry irrigated areas.
Vicia villosa rothreduced nitrogen applicationspring wheatyieldwater use efficiencynorthwest irrigated areas
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