优化氮肥配置提高冬小麦-夏玉米贮墒旱作栽培水氮利用效率

Improving water and nitrogen use efficiency of no-irrigating winter wheat-summer maize under storing available water before growing by optimizing nitrogen fertilizer allocation

为探明与冬小麦-夏玉米周年贮墒旱作节水栽培模式相配套的氮肥高效施用技术,基于贮墒旱作栽培(冬小麦和夏玉米灌底墒水或出苗水,生育期内不灌水),在全年施氮量360kg/hm^(2)下开展了前后茬作物施氮量配比不同的大田试验。试验设置4种施氮处理,分别为冬小麦120kg/hm^(2)+夏玉米240kg/hm^(2)(W_(0)N_(1));冬小麦180kg/hm^(2)+夏玉米180kg/hm^(2)(W_(0)N_(2));冬小麦240kg/hm^(2)+夏玉米120kg/hm^(2)(W_(0)N_(3)),并设常规灌溉施肥模式(冬小麦灌底墒水+拔节水+开花水,施纯氮180kg/hm^(2);夏玉米灌出苗水,施纯氮180kg/hm^(2))为对照(W_(1)N_(c))。试验测定了冬小麦-夏玉米周年物质生产与水、氮效率等指标。结果表明:在全年施氮总量一定的前提下,贮墒旱作栽培适当减少夏玉米季施氮量、增加冬小麦季施氮量可提高冬小麦籽粒产量和蛋白质含量,稳定夏玉米产量,使全年水、氮利用效率和总产量增加,W_(0)N_(3)比W_(0)N_(2)和W_(0)N_(1)全年产量分别增加3.20%~5.17%和6.84%~9.94%;与常规模式(W_(1)N_(c))相比,贮墒旱作模式减少灌溉量150mm,各处理周年产量降低,但W_(0)N_(3)在多雨年份的产量差异不显著,在干旱年份减产11.38%,且在不同年型的周年水分利用效率(WUE)和氮素利用效率(NUE)均显著提高。因此,在贮墒旱作和有限施氮的条件下,将氮肥较多分配给冬小麦季更有利于实现增产增效。

In order to clarify the high-efficiency application technology of nitrogen fertilizer matched with the cultivation mode of no-irrigating winter wheat-summer maize under storing available water before growing,in this study,field experiment with different nitrogen application rates of previous and subsequent crops was carried out under the annual nitrogen application rate of 360kg/hm^(2).The experiment included four nitrogen treatments:1)120kg/hm^(2) for winter wheat+240kg/hm^(2) for summer maize+no irrigation in spring(W_(0)N_(1));2)180kg/hm^(2) for winter wheat+180kg/hm^(2) for summer maize+no irrigation in spring(W_(0)N_(2));3)240kg/hm^(2) for winter wheat+120kg/hm^(2) for summer maize+no irrigation in spring(W_(0)N_(3));and 4)180kg/hm^(2) for winter wheat+180kg/hm^(2) for summer maize+traditional irrigation at jointing and anthesis for winter wheat in spring(W_(1)N_(c)).The indexes of crop material production and water and nitrogen efficiency were measured.The results showed that:The grain yield and protein content of winter wheat increased,grain yield of summer maize stabilized,anniversary grain yield,water use efficiency and nitrogen use efficiency significantly improved with more nitrogen fertilizer applied at winter wheat season under no-irrigating crop production system.Compared with W_(0)N_(2)and W_(0)N_(1),the annual grain yield of W_(0)N_(3)increased by 3.20%-5.17%and 6.84%-9.94%,respectively.In addition,there was no significant difference in anniversary grain yield between the W_(1)N_(c) and W_(0)N_(3)in wet year,while yield loss by 11.38%under W_(0)N_(3) was found in the dry year.W_(0)N_(3) always achieved the highest anniversary water use efficiency and nitrogen use efficiency whether it was a dry or wet year.Therefore,more nitrogen fertilizer should be allocated in winter wheat season to improve anniversary grain yield,water use efficiency and nitrogen use efficiency under limited nitrogen application rate and no-irrigation winter wheat-summer maize rotation under storing available water before growing.