Relay-intercropping soybean with maize maintains soil fertility and increases nitrogen recovery efficiency by reducing nitrogen input  

作　　者：Qing Du Li Zhou Ping Chen Xiaoming Liu Chun Song Feng Yang Xiaochun Wang Weiguo Liu Xin Sun Junbo Du Jiang Liu Kai Shu Wenyu Yang Taiwen Yong 

机构地区：[1]College of Agronomy,Sichuan Agricultural University,Chengdu 611130,Sichuan,China [2]College of Environment,Sichuan Agricultural University,Chengdu 611130,Sichuan,China [3]Sichuan Engineering Research Center for Crop Strip Intercropping System/Key Laboratory of Crop Ecophysiology and Farming System in Southwest,Ministry of Agriculture,Chengdu 611130,Sichuan,China [4]Yibing Academy of Agricultural Sciences,Yibing 644000,Sichuan,China [5]Shehong Farm Bureau,Suining 629200,Sichuan,China

出　　处：《The Crop Journal》2020年第1期140-152,共13页作物学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(31671625,31271669);the National Key Research and Development Program of China(2016YFD0300202)

摘　　要：Optimized nitrogen(N)management can increase N-use efficiency in intercropping systems.Legume-nonlegume intercropping systems can reduce N input by exploiting biological N fixation by legumes.Measurement of N utilization can help in dissecting the mechanisms underlying N uptake and utilization in legume-nonlegume intercropping systems.An experiment was performed with three planting patterns:monoculture maize(MM),monoculture soybean(SS),and maize-soybean relay intercropping(IMS),and three N application levels:zero N(NN),reduced N(RN),and conventional N(CN)to investigate crop N uptake and utilization characteristics.N recovery efficiency and 15N recovery rate of crops were higher under RN than under CN,and those under RN were higher under intercropping than under the corresponding monocultures.Compared with MM,IMS showed a lower soil N-dependent rate(SNDR)in 2012.However,the SNDR of MM rapidly declined from 86.8%in 2012 to 49.4%in 2014,whereas that of IMS declined slowly from 75.4%in 2012 to 69.4%in 2014.The interspecific N competition rate(NCRms)was higher under RN than under CN,and increased yearly.Soybean nodule dry weight and nitrogenase activities were respectively 34.2%and 12.5%higher under intercropping than in monoculture at the beginning seed stage.The amount(Ndfa)and ratio(%Ndfa)of soybean N2 fixation were significantly greater under IS than under SS.In conclusion,N fertilizer was more efficiently used under RN than under CN;in particular,the relay intercropping system promoted N fertilizer utilization in comparison with the corresponding monocultures.An intercropping system helps to maintain soil fertility because interspecific N competition promotes biological N fixation by soybean by reducing N input.Thus,a maize-soybean relay intercropping system with reduced N application is sustainable and environmentally friendly.Optimized nitrogen(N) management can increase N-use efficiency in intercropping systems.Legume-nonlegume intercropping systems can reduce N input by exploiting biological N fixation by legumes.Measurement of N utilization can help in dissecting the mechanisms underlying N uptake and utilization in legume-nonlegume intercropping systems.An experiment was performed with three planting patterns:monoculture maize(MM),monoculture soybean(SS),and maize-soybean relay intercropping(IMS),and three N application levels:zero N(NN),reduced N(RN),and conventional N(CN) to investigate crop N uptake and utilization characteristics.N recovery efficiency and15 N recovery rate of crops were higher under RN than under CN,and those under RN were higher under intercropping than under the corresponding monocultures.Compared with MM,IMS showed a lower soil N-dependent rate(SNDR) in 2012.However,the SNDR of MM rapidly declined from 86.8% in2012 to 49.4% in 2014,whereas that of IMS declined slowly from 75.4% in 2012 to 69.4% in2014.The interspecific N competition rate(NCRms) was higher under RN than under CN,and increased yearly.Soybean nodule dry weight and nitrogenase activities were respectively34.2% and 12.5% higher under intercropping than in monoculture at the beginning seed stage.The amount(Ndfa) and ratio(%Ndfa) of soybean N2 fixation were significantly greater under IS than under SS.In conclusion,N fertilizer was more efficiently used under RN than under CN;in particular,the relay intercropping system promoted N fertilizer utilization in comparison with the corresponding monocultures.An intercropping system helps to maintain soil fertility because interspecific N competition promotes biological N fixation by soybean by reducing N input.Thus,a maize-soybean relay intercropping system with reduced N application is sustainable and environmentally friendly.

关 键 词：Maize-soybean relay intercropping Reduced nitrogen Biological nitrogen fixation Nitrogen recovery efficiency Soil nitrogen dependent rate 

分 类 号：S513[农业科学—作物学] S565.1S158