玉米大豆间作减量施氮对当季作物农艺性状、经济效益和后茬小麦产量的影响

Effects of Nitrogen Reduction Application of Summer Maize-Soybean Intercropping on Agronomic Traits and Economic Benefits as well as Its Yield of Subsequent Wheat

【目的】旨在明确施氮量对夏播玉米间作大豆的作物产量构成、经济效益及其后茬冬小麦产量的影响。【方法】2022—2023年,在玉米大豆条带复合种植主要推广区域山东省禹城市选择代表性农田,夏播季设置玉米单作(施肥量225 kg·hm^(-2))、大豆单作(施氮量45 kg·hm^(-2))、玉米大豆间作全量施氮(施氮量270 kg·hm^(-2),玉米条带和大豆条分别施氮225和45 kg·hm^(-2))、玉米大豆间作减量施氮(施氮量135 kg·hm^(-2),玉米条带和大豆条带分别施氮90和45 kg·hm^(-2))。后茬种植小麦,不设施肥处理。分析不同夏播处理对当季作物光合特性、农艺性状、经济效益以及后茬小麦产量的影响。【结果】种植模式和施氮量不同均会影响间作作物生长发育。相对玉米单作种植,间作减量施氮在拔节期和抽雄期玉米叶片的叶绿素含量以及P_(n)、G_(s)、C_(i)和T_(r)显著降低;而间作全量施氮中玉米叶片P_(n)、G_(s)和T_(r)分别显著提高了8.8%、10%、11.6%。不同间作处理下大豆叶绿素含量均降低,叶片P_(n)、G_(s)、T_(r)受到抑制,农艺性状方面茎长增加、单株荚数降低,导致产量降低65.1%—68.4%。间作全量施氮的玉米农艺性状和产量与单作玉米没有显著差异,且该模式下经济效益最高,达到22607元/hm^(2),而减量施氮下玉米的穗长、穗粒数、百粒重等农艺性状显著降低,产量下降14.8%。但总体来说玉米大豆间作两种施氮量处理的土地当量比均大于1,经济效益、作物吸氮量分别较玉米单作提高4.8%—11.5%和19.7%—38%。后茬冬小麦在不施肥情况下,夏播季间作全量施氮的后茬冬小麦籽粒产量、吸氮量均高于其他处理,间作减量施氮与夏播玉米单作的后茬冬小麦产量无显著差异。【结论】从农艺性状、产量、经济效益以及对后茬作物影响的综合分析,间作全量施氮效果优于间作减量施氮,但统筹考虑产量、经济效益和环境效益,间作种植施氮量还可在全量施氮的基础上进一步优化。

【Objective】The purpose of this study was to determine the effects of nitrogen application amount on the yield composition,economic benefit of summer sowing intercropping crops and the yield of winter wheat.【Method】From 2022 to 2023,the representative farmlands were selected in Yucheng C_(i)ty,Shandong Province,which was the main extension area of maize-soybean strip intercropping.Maize monoculture(Nitrogen application rate:225 kg·hm^(-2)),soybean monoculture(Nitrogen application rate:45 kg·hm^(-2)),maize-soybean intercropping with full nitrogen application(Nitrogen application rate:270 kg·hm^(-2)),maize-soybean intercropping with reduced nitrogen application(Nitrogen application rate:135 kg·hm^(-2))were set up in summer sowing season,and the subsequent crops were planted with wheat without fertilizer treatment.The effects of different summer sowing treatments on photosynthetic characteristics,agronomic traits,economic benefits and yield of subsequent wheat were analyzed.【Result】Both planting pattern and nitrogen application amount had significant effects on crop growth and development.Compared with maize monoculture,the chlorophyll content,P_(n),G_(s),C_(i)and T_(r)of maize leaves were significantly decreased by intercropping reduced nitrogen application(135 kg·hm^(-2)).However,the P_(n),G_(s)and T_(r)of leaves of intercropping full nitrogen maize(270 kg·hm^(-2))were significantly increased by 8.8%,10%and 11.6%,respectively.Intercropping system resulted in decreased chlorophyll content of soybean,inhibited leaf P_(n),G_(s),and Tr.In terms of agronomic characteristics,stem length increased,pod number per plant decreased,and yield decreased by 65.1%-68.4%.There was no significant difference in the agronomic characteristics and yield of maize under the intercropping system with full nitrogen application,and the economic benefit was the highest under this system,reaching 22607 yuan/hm^(2),while the agronomic characteristics such as ear length,grain number per ear and hundred-grain weight of maize under reduced nitrogen application significantly decreased,and the yield decreased by 14.8%.However,in general,the land equivalent ratio of both maize and soybean treatments was also greater than 1.Economic benefit and nitrogen uptake were increased by 4.8%-11.5%and 19.7%-38%compared with monocrop.When winter wheat was not fertilized,the grain yield and crop nitrogen uptake of aftercrop winter wheat with full nitrogen application in summer sowing were higher than that under other treatments,and there was no significant difference between the yield of winter wheat with reduced nitrogen application between summer sowing seasons and that of winter wheat with summer sowing maize.【Conclusion】Therefore,from the comprehensive analysis of agronomic characteristics,yield and economic benefits as well as the effects on aftercrop,the effect of total nitrogen application in intercropping was better than that of reduced nitrogen application in intercropping.However,considering the yield,economic and environmental benefits,the amount of nitrogen application in intercropping should be further optimized.