Study On High-efficiency Water And Fetilizer Management Of Winter Wheat Under Limited Irrigation Conditions In Weibei Plateau

Water shortage and nutrient deficiency are key factors that restricted the winter wheatproduction in Weibei dryland and crop production in arid and semiarid areas. At present, lowwater and nitrogen use efficiency and waste of water resource still exist in traditional fertilizerapplication and irrigation patterns in Weibei drylamd. Therefore, searching for effectivemeasures to improve the use of limited precipitation and nutrient and improve the soil fertilityis the key to obtain high and stable yields of winter wheat as well as the important issues ofagricultural production.In this study, we dealt with the above problems in the way of setting winter wheat fieldexperiments in Chengcheng County, Shaanxi Province during September2009to June2011.The treatments contained farmers' modes with traditional fertilization application andirrigation patterns and optimized modes with integration of optimized nitrogen withsupplementary irrigation, straw mulch and organic manure. The field experiment was carriedout to study the effects of the farmers' modes and optimized modes on the winter wheat yield,water use efficiency soil water change, absorption of nitrogen and nitrogen use efficiencyunder limited irrigation in Weibei dryland. The research was to provide theoretical basis forthe cultivation measures of grains yield and resource using efficiency in winter wheat of aridand semiarid areas. The main conclusions included:1The farmers' conventional fertilizer application treatment (farmers'mode1,FM1)increased winter wheat yield by32.7%compared to the no nitrogen treatment(CK). Theconventional fertilizer application with irrigation in reviving stage (farmers'mode2,FM2)could increased the yield by39.6%,85.3%compared with the FM1and CK,respectively. Theoptimized mode treatments winter wheat increased by100.5%,51.6%,8.5%compared withthe CK, FM1and FM2, respectively.2Correlation analysis of the yield component showed that the effective panicles madethe greatest contribution to the grain yield in yield component. Application of nitrogenfertilizer and irrigation can significantly improve the total population of winter wheat stems(spikes) number. Comparing with the traditional fertilization and irrigation, the topdressingnitrogen and supplementary irrigation in jointing stage, straw mulch and organic manure can further increase the effective panicles of wheat.3The population amount results showed that each treatment was all increased afteremergence, reached the highest at reviving stage, and decreased afterwards. Before thereviving stage, dry biomass and population were the highest in the farmers' mode2treatment(farmers' traditional fertilization and irrigation), while there was no significant differenceamong all the treatments on the population amount. After the topdressing nitrogen andsupplementary irrigation in jointing stage, significant differences were showed in thepopulation amount and dry biomass; dry biomass and population were highest in theoptimized mode3-1. Nitrogen and irrigation could improve the population and dry biomass.4Application of nitrogen fertilizer and irrigation could increase the total waterconsumption, and Application of nitrogen fertilizer could improve water use efficiencysignificantly. Compared with the traditional fertilizer application and irrigation, thetopdressing nitrogen and supplementary irrigation in jointing stage could significantlyincrease the WUE by15.2%~36.9%. The maximum WUE in the experiment was optimizedmodes3-1, the first year was12.18kg·hm~-2·mm~-1and the second year was13.34kg·hm~-2·mm~-1.It was5.4%~15.9%higher than other optimized modes, so straw mulch and organic fertilizerapplication could improve the water use efficiency.5According to two-year results, application of nitrogen fertilizer and irrigation inreviving stage could significantly promote the nitrogen accumulation in0~200cm soil, whilethe straw mulch could decrease the residual nitrate N in the soil profiles. The topdressingnitrogen and supplementary irrigation in jointing stage could significantly promote nitrogenaccumulation,nitrogen recovery efficiency and agronomic nitrogen use efficiency, comparedwith the traditional fertilizer application and irrigation. The maximum NRE in the experimentwas optimized modes3-1, which was increased by32.8%comparing with the FM2. Strawmulch could not increase the nitrogen accumulation and nitrogen use efficiency significantly,but combined with straw mulch and organic fertilizer application can promote winter wheatnitrogen uptake, significantly increase nitrogen recovery efficiency and agronomic nitrogenuse efficiency.The research was carried out to study the effects of the farmers' modes and optimizedmodes on the winter wheat yield under limited irrigation in Weibei dryland. It was to providetheoretical basis for the cultivation measures of high grains yield and resource usingefficiency in winter wheat of arid and semiarid areas. The results showed that optimizedmodes could improve the economic benefits significantly compared to famers'modes. Theoptimized mode3-1was ideally efficient water and nitogen management cultivation mode,which nitrogen application amount was150kg/hm2combination with the ratio of base fertilizer and topdressing at2:1, nitrogen topdressing with irrigation supplement, straw mulchwith manure application. It was worth of expending to large area under limited irragtioncondition in Weibei highland.