不同覆盖方式下减氮对玉米生长与氮素吸收、运转和分配的影响

以玉米正红505为试验材料,采用两因素随机区组设计,设置3个氮肥水平(常规施氮、减氮20%和减氮40%)和3种覆盖方式(地膜覆盖、秸秆覆盖和无覆盖),以不施氮肥无覆盖为CK,研究不同覆盖方式和氮肥水平对土壤水分与全氮含量、玉米干物质积累、氮素吸收、运转和分配及产量的影响。结果表明:(1)与CK和减氮40%处理相比,耕层土壤水分和全氮含量以覆盖处理和较高氮肥水平处理较高;(2)与减氮40%处理相比,较高氮肥水平处理玉米株高、茎粗、叶面积和单株干物质积累量均较高;较高氮肥水平下,覆盖处理株高、茎粗、单株叶面积和单株干物质量高于无覆盖处理,尤其是地膜覆盖处理;(3)较高氮肥水平有利于玉米植株氮素积累、转运,减氮20%下地膜覆盖处理和常规施氮下覆盖处理玉米籽粒和植株氮素积累总量较高,并能促进茎叶氮素向籽粒运转,进而提高氮收获指数、氮肥偏生产力、氮农学利用率;(4)玉米籽粒产量随氮肥水平的提高而增加,但增产的幅度逐渐降低;地膜覆盖有明显增产作用,在减氮40%条件覆盖秸秆有一定增产效果;在减氮20%条件覆盖地膜可获得全氮不覆盖处理同等以上产量。综合上述结果,减氮20%下地膜覆盖处理存在玉米高产和氮肥减施并行的可能。

Effects of different decreased-nitrogen and mulching patterns on growth of maize and nitrogen uptake,translocation and distribution

With"zhenghong 505"as the testing material,two-factor randomized block design was used,and three nitrogen fertilizer levels(normal nitrogen application,20%reduction of nitrogen,40%reduction of nitrogen),three mulching patterns(plastic film mulching,straw mulching and no mulching)and CK(no nitrogen and no mulching)were set up to study the influence of nitrogen level and mulching pattern on soil water content,soil total nitrogen content,dry matter accumulation,nitrogen uptake,translocation and distribution,yield of maize.The results showed that:(1)Comparing with CK and 40%reduction of nitrogen,the topsoil moisture and total nitrogen content of mulched treatment and the higher nitrogen levels treatment were higher;(2)Comparing with 40%reduction of nitrogen,the average plant height,stem diameter,leaf area and dry weight of the higher nitrogen levels treatment were increased;mulched under normal nitrogen application and 20%reduction of nitrogen were also higher than no mulching treatment,especially in plastic film mulching;(3)The higher nitrogen levels were helpful for nitrogen accumulation and translocation in maize,plastic film mulching under 20%reduction of nitrogen and mulched under normal nitrogen application improved total nitrogen accumulation of grain and plant,increased nitrogen nutrient transportation from stem and leaf to grain,and then enhanced nitrogen harvest index,nitrogen partial productivity,and agronomic nitrogen use efficiency;(4)The yield of maize increased with nitrogen levels,but the increase rate was progressively lower;plastic film mulching treatment had the significant effects on yield,straw mulching under 40%reduction of nitrogen could improve yield to a certain extent;plastic film mulching under 40%reduction of nitrogen could increase higher yield than no mulching under normal nitrogen application.All the results showed that,plastic film mulching under 20%reduction of nitrogen had the possibility to increase yield of maize and reduce nitrogen fertilization simultaneity.