油菜秸秆还田及氮肥减量对夏玉米生长发育及产量的影响

Effects of rape straw returning and reduction of nitrogen fertilizer on the growth and yield of summer maize

于2018、2019连续2年在湖南省桃源县木塘垸乡设计3种油菜秸秆还田量(移除、半量还田、全量还田)与3种氮肥施用量(减氮40%、减氮20%、当地常规施氮量)2因素裂区试验,探究不同油菜秸秆还田量和氮肥施用量处理对夏玉米生长发育和产量形成的影响。结果表明:夏玉米生育期随着秸秆还田量的增加和施氮量的增加略有延长;在秸秆还田的第1年,叶面积指数、地上部总生物量、产量、氮肥偏生产力等变化主要与施氮量有关,秸秆作用不明显;第2年,大多数指标均以秸秆半量还田+减氮20%的组合效果最好,其吐丝期叶面积指数、成熟期地上部总生物量、实际产量较秸秆移除+常规施氮组合的分别提高18.8%、8.2%、7.6%,在同一施氮量下,秸秆还田处理的氮肥偏生产力较秸秆移除处理的高;2年的油菜秸秆还田及氮肥减量处理对玉米的各农艺性状影响均不大,大多数指标差异无统计学意义。可见,秸秆还田具有良好的减氮增效的作用,可在洞庭湖区油菜–夏玉米复种模式下推广,且以油菜秸秆半量还田+氮肥减量20%的组合为宜。

A two-factors split zone design including three types of rape straw returning(straw removal,straw half returning and straw full returning)and three types of nitrogen fertilizer application(reduction 40%of nitrogen fertilizer,reduction 20%of nitrogen fertilizer and conventional nitrogen application)were performed for two consecutive years,2018 and 2019,in Mutangyuan Township,Taoyuan County,Hunan Province,aiming to investigate the effects of different amount of rape straw returning and nitrogen fertilizer application on the growth and yield formation of summer maize.Results showed that the growth period of maize increased slightly with the enhancement of straw returning and nitrogen fertilizer applied.In the first year of straw returning to field,changes in leaf area index,total above-ground biomass,grain yield and partial factor productivity of nitrogen fertilizer were mainly related to the amount of nitrogen fertilizer applied,and the effect of straw was not obvious.In the second year,most of the indicators of the combination of straw half returning and reduction 20%of nitrogen fertilizer were the best.The leaf area index at the spinning stage,the total above-ground biomass at maturity,and grain actual yield were increased by 18.8%,8.2%,and 7.6%respectively,compared with the conventional nitrogen application treatments with straw removal.Under the same nitrogen application,the partial productivities of nitrogen fertilizer with straw returning were higher.Rape straw returning and nitrogen fertilizer reduction treatments had little effect on the agronomic characteristics of maize in 2 years,and most of the indicators were not statistically different.It can be concluded that straw returning has a good effect of reducing nitrogen fertilizer using and increasing yield.This discovery can be applied into the rape-summer maize multiple cropping mode in the Dongting Lake area,and the combination of rape straw half returning and reduction 20%of nitrogen fertilizer is appropriate.