不同生态区覆盖方式对玉米氮转运、产量与水氮利用效率的影响

Effects of Mulch Measures on Nitrogen Transport,Yield and Water and Nitrogen Use Efficiency of Maize in Different Ecological Zones

[目的]明确覆盖方式对西北不同生态区玉米氮转运、产量与水氮利用效率的影响效果,为缓解旱作区作物生产同水资源短缺之间尖锐矛盾提供科学依据。[方法]于2022年在甘肃省兰州市榆中县、甘肃省定西市安定区和陕西省咸阳市长武县进行田间试验,设置干旱偏旱区(YZ)、半干旱区(DX)和半干旱偏湿润区(CW)3个不同降水条件生态区,分析地膜覆盖(FM)和秸秆覆盖(SM)对于玉米不同器官干物质和氮素积累、分配、转运、水氮利用效率及产量形成的影响。[结果](1)覆盖措施显著影响土壤环境,提高各生态区0—100 cm土壤含水率和表层土壤无机氮含量,FM提高了全生育期土壤表层温度,SM在生育后期具有保温作用。(2)各生态区吐丝期和成熟期农艺性状和干物质累积量总体表现为CW>YZ>DX,与CK相比覆盖处理提高了玉米吐丝期株高、茎粗和成熟期株高、茎粗、节数、穗位高及干物质累积量,尤其是FM处理。(3)CW的覆盖处理玉米籽粒和植株氮素积累总量在3个生态区中最高,覆盖促进茎叶氮素向籽粒运转,进而提高氮收获指数和水分利用效率,但DX的FM氮收获指数和YZ的FM水分利用效率较CK增加幅度最高,分别达6.91%和70.58%。(4)玉米籽粒产量在各生态区表现为CW>YZ>DX,覆盖处理对各生态区均有明显增产作用,增产效果FM>SM。其中DX和YZ的FM增产幅度高于CW,达52.33%和52.55%,但CW的SM增加幅度最高,达16.76%。[结论]地膜覆盖和秸秆覆盖通过改善土壤温度、水分和表层无机氮含量进而提高玉米水氮利用效率和产量,其中地膜覆盖效果最佳。而半干旱偏旱区地膜覆盖对产量的响应最显著,半干旱偏湿润区秸秆覆盖的响应最佳。

[Objective]The aims of this study are to clarify the effects of mulching methods on maize nitrogen transport,yield and water and nitrogen utilization efficiency in different ecological zones in northwest China,and to provide a scientific basis for mitigating the acute conflicts between crop production and water scarcity in dryland areas.[Methods]A field experiment was conducted in 2022 in Yuzong County,Lanzhou City,Gansu Province,Anding District,Dingxi City,Gansu Province,and Changwu County,Xianyang City,Shaanxi Province,with three ecological zones with different precipitation conditions,namely,arid dry zone(YZ),semi-arid zone(DX),and semi-moisture dry zone(CW),to investigate the effects of film mulching(FM)and straw mulching(SM)on the accumulation,distribution,and efficiency of N and N utilization,as well as the accumulation,distribution and efficiency of N and N utilization of maize organs in three different ecological zones in the northwest China.The effects of FM and SM on dry matter and nitrogen accumulation,distribution,transfer,water and nitrogen utilization efficiency and yield formation in different organs of maize were investigated.[Results](1)Mulching measures significantly affected the soil environment,increased the water content of 0—100 cm soil layer and inorganic nitrogen content of surface soil in all ecological zones,and FM increased the surface temperature of soil during the whole reproductive period,while SM had a heat preservation effect in the late reproductive stage.(2)Agronomic traits and dry matter accumulation at spitting and maturity stages in each ecological zone generally showed the order:CW>YZ>DX,and the mulching treatment improved plant height and stem thickness at spitting stage and plant height,stem thickness,number of nodes,ear height and dry matter accumulation at maturity stage of maize compared with CK,especially in the FM treatment.(3)Total corn grain and plant nitrogen accumulation of the mulch treatments in CW was the highest among the three ecological zones,and the mulch promoted the operation of stem and leaf nitrogen to the kernel,which in turn increased the nitrogen harvest index and water use efficiency,but the nitrogen harvest index of FM in DX and the water use efficiency of FM in YZ had the highest increase compared with that in CK,which amounted to 6.91% and 70.58%,respectively.(4)Corn kernel yield in all ecological zones followed the order:CW>YZ>DX,and mulching treatments had significant yield increases in all ecological zones,with yield increase effects of FM>SM,in which the yield increases of FM in DX and YZ were higher than that of CW,amounting to 52.33% and 52.55%,respectively,but the increase of SM in CW was the highest,amounting to 16.76%.[Conclusion]Film mulching and straw mulching improve water and nitrogen utilization efficiency and yield of maize by improving soil temperature,moisture and surface inorganic nitrogen content,among which film mulching has the best effect.In the semi-arid and dry zone,the most significant response of mulching is on yield,and the best response is on straw mulching in the semi-humid and dry zone.