耕作方式和秸秆覆盖对旱地麦豆轮作下小麦籽粒产量、蛋白质含量和土壤硝态氮残留的影响

Effects of tillage method and straw mulching on grain yield and protein content in wheat and soil nitrate residue under a winter wheat and summer soybean crop rotation in drylands

为明确耕作方式和秸秆覆盖对旱地麦豆轮作下小麦籽粒产量、蛋白质含量和土壤硝态氮残留的影响,2014年10月-2016年6月,利用设置在豫西典型旱作区的麦豆轮作栽培模式长期定位试验,选取传统翻耕、翻耕覆盖、旋耕和旋耕覆盖4个处理,比较了小麦氮素吸收利用、籽粒产量、蛋白质含量以及土壤硝态氮残留量。结果表明,与翻耕相比,旋耕不影响小麦产量,但花后氮素积累量、籽粒蛋白质含量和蛋白质产量分别降低60.0%、8.6%和13.0%,而成熟期0~200cm土层硝态氮残留量显著提高28.6%。同一耕作方式下,秸秆覆盖较无覆盖不仅显著提高了穗数、穗粒数、千粒重和收获指数,还提高了拔节前和开花后的氮素积累量,促进了营养器官氮素向籽粒中转运,从而使翻耕覆盖的籽粒产量、氮素吸收效率、籽粒蛋白质含量和蛋白质产量较翻耕分别提高11.5%、13.5%、7.4%和21.3%,旋耕覆盖较旋耕也分别提高23.0%、39.5%、12.8%和38.5%。在试验进行7年后的小麦成熟期,翻耕覆盖0~200cm土层硝态氮残留量较翻耕降低31.3%,旋耕覆盖较旋耕也降低51.4%。因此,秸秆覆盖不仅可提高旱地麦豆轮作下小麦产量、蛋白质含量和氮素吸收效率,还能降低土壤硝态氮的残留量,是兼顾旱地小麦高产优质和环境友好生产的有效途径,尤其以旋耕覆盖效果突出。

Based on a long-term field experiment to compare different cropping patterns,conducted in western Henan province,the effects of tillage method and straw mulching on wheat productivity and soil nitrate residue in drylands under a winter wheat(Triticum aestivum)and summer soybean(Glycine max)rotation were investigated from October2014to June2016.The experiment included four treatments:plough tillage(PT);plough tillage with straw mulching(PTSM);rotary tillage(RT);and rotary tillage with straw mulching(RTSM).The plant nitrogen(N)absorption and utilization,grain yield,grain protein content in wheat and the nitrate residue in the0-200cm soil depth were measured.Compared with PT,RT did not change grain yield,but decreased post-anthesis N accumulation,grain protein content and protein yield in wheat by60.0%,8.6%and13.0%,respectively,and increased nitrate residue in0-200cm soil depth by28.6%.Compared with no mulching,straw mulching with the same tillage method increased not only the spike numbers,kernels per spike,1000-kernel weight and harvest index,but also the pre-jointing and post-anthesis N accumulation and N translocation from vegetative organs to the grain in wheat.As a result,the grain yield,N uptake efficiency,grain protein content and protein yield under PTSM were11.5%,13.5%,7.4%and21.3%higher than that under PT,and the corresponding values for RTSM were,respectively,23.0%,39.5%,12.8%and38.5%higher than that under RT.At wheat maturity after seven years of continuous cropping,PTSM decreased the nitrate residue in the0-200cm soil depth by31.3%compared with PT,whereas RTSM decreased the nitrate residue by51.4%compared with RT.Therefore,straw mulching is an alternative cropping technique because it can not only increase the N uptake efficiency,grain yield,grain protein content and protein yield in wheat,but also decrease soil nitrate residue under winter wheat and summer soybean rotation in drylands,especially for the RTSM treatment.