Effects Of Field Configuration Of Maize Soybean Intercropping On Crop Yield,nutrient Uptake And Interspecific Relationship In Upland Red Soil

Red soil in south China is one of the most important types of soil in China.It has the characteristics of acid,barren and sticky.The distribution area and precipitation are uneven in time and space.In addition,people abuse natural resources,which leads to the deterioration of ecological environment in red soil area and restricts the development of agriculture in red soil.Intercropping could improve land use efficiency,increase crop yield,increase farmers’income,improve soil fertility and so on.On the other hand,intercropping plays an important role in China’s agricultural development.In order to screen out the suitable maize soybean row ratio allocation system for red soil upland planting,we conducted an experiment in Jinxian Red Soil Research Institute in 2019.Taking maize and soybean sole system as the CK,we analyzed the crop growth under three different bandwidth modes（2.0m,2.4m,2.8m）and three different corn soybean row ratios（2:2,2:3,2:4）,It is expected to provide a scientific theoretical basis for the development of high-yield and ecological agriculture.The main conclusions are as follows:1.In the experiment in 2019,with the growth of maize,plant height and leaf area index（LAI）increased first and then decreased;dry matter accumulation of maize increased continuously and reached the maximum in harvest period;with the same bandwidth,increasing row ratio configuration increased soybean yield;with the same row ratio,increasing bandwidth decreased soybean yield.Under the intercropping system,the yield of maize and soybean was 6977.78 kg·hm^-2and 736.4 kg·hm^-2,respectively.2.The intercropping treatments with different bandwidth and row ratio showed different agronomic characters.There was no significant difference in ear diameter,rows per ear,grains per row and 1000 grain weight among different intercropping treatments.Different bandwidth and row ratio had a greater effect on ear length and bald tip length.The results showed that plant height,stem diameter,number of pods per plant,number of pods per plant,100 seed weight,number of seeds per plant,number of pods per plant,seed weight per plant and yield of soybean were the highest under the system of 2.4 m width and 2:4 row ratio.When the width increased from 2 m to 2.8 m,the plant height,stem diameter,100 seed weight,pod number per plant,seed weight per plant and yield increased first and then decreased;when the width increased from 2.4 m to 2.8 m,the plant height,pod number,seed number per plant,seed weight per plant and soybean yield increased with the increase of one row of soybean.3.In the two-year experiment,the average land equivalent ratio（LER）was 1.59 under the mode of 2.4 m bandwidth and 2:4 row ratio,the actual yield loss（AYL_M）and the dominance index（IA_M）of maize intercropping were higher,the yield of crop group was better,and the average economic benefit was higher.With the same bandwidth and increasing row ratio,LER,relative crowding index（K）,AYL,maize occupation power（A_M）,maize competition ratio（CR_M）,economic benefit（EB）,maize harvest index and crop yield showed an increasing trend;with the same row ratio and the bandwidth increasing from 2.4 m to 2.8 m,LER,K,AYL,A_M,CR_M,EB and maize harvest index showed a decreasing trend,while the yield of intercropping maize decreased.4.The accumulation and utilization efficiency of nitrogen（N）,phosphorus（P）and potassium（K）were different under different intercropping patterns,which indicated that the utilization of elements could be optimized by planting different intercropping patterns of maize and soybean.In the intercropping,the N accumulation of maize soybean showed the advantage of intercropping in the system of bandwidth 2.4 m and row ratio of 2:4compared with other intercropping treatment.In this experiment,the average N,P and K accumulation of maize and soybean in the 2.4 m bandwidth was higher than that in the 2.0m bandwidth,which indicated that increasing the bandwidth was beneficial to the increase of N,P and K Accumulation under suitable planting conditions.With the bandwidth of 2.4m and 2.8 m,the utilization efficiency of maize N,P and K was improved by adding a row of soybean,which indicated that reducing the interspecific distance under the appropriate bandwidth mode was beneficial to improve the utilization of all elements.To sum up,in the experiment of 2019,when the bandwidth is 2.4 m and the row ratio is 2:4,the maize yield was 6977.78 kg·hm^-2and the soybean yield was 736.4 kg·hm^-2,The average LER was 1.59,AYL_Mand IA_Mwere higher,showing the advantages of intercropping,N accumulation and EB,which can provide a reference for maize soybean intercropping system in red soil dryland of south China.