减量施氮及秸秆深埋对春玉米地土壤电导率和硝态氮淋溶的影响

Effects of Reduced Nitrogen Application and Deep Burial of Straw on Soil Electrical Conductivity and Nitrate Nitrogen Leaching in Spring Maize Field

通过在中国科学院长武黄土高原农业生态试验站半覆膜种植春玉米大田试验,研究了减氮及秸秆深埋对土壤电导率、土壤硝态氮淋溶和玉米产量的影响,旨在为提高氮肥利用效率和保护环境提供理论依据。试验设5个处理3个重复,处理包括不施氮(CK)、常规施氮(CON1,N 250kg/hm2)、常规施氮加秸秆(CON2,N 250kg/hm2+秸秆)、减量施氮(CR1,N 200kg/hm2)和减量施氮加秸秆(CR2,N 200kg/hm2+秸秆)。测量了春玉米各生育期土层剖面土壤电导率、收获期土壤硝态氮含量和春玉米产量。结果表明:土壤电导率在分蘖期、拔节期40—150cm土层出现峰值,在抽穗期、成熟期40—200cm土层出现峰值,峰值范围下移。在0—150cm土层范围内,土壤电导率整体呈现CON2>CON1,CR2>CR1。在0—150cm土层范围内,常规施氮土壤电导率高于减量施氮。与常规施氮相比,减量施氮减少了土壤剖面硝态氮含量,同时,采取秸秆深埋措施也能减少土壤剖面硝态氮含量,并延缓硝态氮的淋溶下移。与常规施氮相比,减量20%施氮增产9.59%。施氮条件下,秸秆深埋时,有利于提高作物产量,提高氮肥增产潜力。秸秆深埋有利于提高土壤电导率,减少土壤硝态氮含量,阻控土壤硝态氮向下淋溶,提高玉米产量。

The effects of reduced nitrogen application and straw deep buried on soil electrical conductivity,yield of maize and residuals of soil nitrate nitrogen were researched through field experiment conducted in spring maize planted with semi-plastic film in the Changwu State Key Agro-Ecological Station,and aimed to provide theoretical support for improving the efficiency of nitrogen use and protecting the environment.The experiment included five treatments with three replicates,no nitrogen fertilization application(CK),conventional nitrogen fertilization application(CON1,N250kg/hm^2),conventional nitrogen fertilization plus straw(CON2,N250kg/hm^2),reduced nitrogen fertilization application(CR1,N200kg/hm^2),and reduced nitrogen fertilization application plus straw(CR2,N200kg/hm^2).The soil electrical conductivity at different growth stages of spring maize was investigated,and the soil nitrate nitrogen content and spring maize yield during the harvest period were measured.The results showed that:the peak values of soil electrical conductivity at the stages of maize tillering and jointing appeared at the soil profile of40-150cm,at the stages of maize heading and maturing the peak values of soil electrical conductivity appeared at the soil profile of40-200cm,and the range of peak value moved down.In the0-150cm soil profile,the soil electrical conductivity followed the order of CON2>CON1,CR2>CR1.In the0-150cm soil layer,the soil electrical conductivity of conventional nitrogen application was higher than those of reduced nitrogen application treatments.Compared with the traditional nitrogen fertilization application,the reduced nitrogen application reduced the nitrate nitrogen content in the soil profile.At the same time,deep buried straw could also reduce the nitrate nitrogen content in the soil profile and postpone the soil nitrate nitrogen leaching.Compared with the traditional nitrogen application,20%reduction of nitrogen fertilization could increase the maize yield by9.59%.On the condition of nitrogen application,deep burying of straw was beneficial to increase crop yield and the potential of nitrogen production.Straw deep burying was beneficial to improve soil electrical conductivity,reduce soil nitrate nitrogen content,control soil nitrate nitrogen leaching and increase corn yield.