Study On Yield Effect And Mechanism Of Different Corn And Soybean Intercropping Patterns In Jilin Corn Belt

In recent years,China's corn production has been excessive,and overall prices have dropped.Jilin Province is also a major province for corn cultivation.Therefore,to improve economic efficiency,it is necessary to transform its structure.Long-term production practices have proven that the intercropping model of agricultural production is superior to the traditional farming model in terms of economic and ecological benefits.This study takes a black soil test plot at the experimental station of Lishu County,Jilin Province as the research object,and sets 4:2?four ridge corn and two ridge soybean?,3:2?three ridge corn and two ridge soybean?,and 2:2?two ridge corn and two ridges soybean?,2:1?two ridge corn and one ridge soybean?four intercropping patterns,and corn,soybean monoculture,six treatments in total.After two years of experiments,the crop growth,yield,nitrogen utilization characteristics,water use efficiency and photosynthetic ecological physiology under intercropping and mono-cropping were studied and the utilization characteristics of different corn?soybean intercropping patterns on crop yield,moisture,light energy,and nitrogen resources were explored to provide a theoretical basis for finding the best intercropping pattern for increasing the benefits of Jilin corn belt under the condition of ensuring corn yield.The results of the study are as follows:1.Intercropping promoted the growth and development of corn and inhibited the growth of soybeans.The results of two years showed that the intercropping maize plant height was lower than that of mono-cropping,and the stem diameter and leaf area were all higher than that of mono-cropping.The dry matter accumulation at the mature stage was increased by an average of 12.0%compared with that of mono-cropping;The plant height of intercropped soybean was higher than that of mono-cropping,and the stem diameter was lower than that of mono-cropping.The dry matter accumulation at maturity was 14.7%lower than that of mono-cropping,and intercropping soybean was less mature than mono-cropping.For the intercropped intercropping seasons,the corn and soybean 4:2 intercropping pattern had a higher stem diameter than other treatments.In 2016,the average dry matter accumulation amount of corn between the 4 and 2 crops was 364.8 g/plant,reaching the highest level.The average dry matter accumulation of 4:2 intercropping soybeans for 3 years was 39.2g/plant,which was the highest.The 4:2 intercropping is more conducive to the growth and development of corn and soybean in the intercropping system.Notice:‘?'means intercrop.2.Corn?soybean have a significant intercropping advantage and increase crop yields.The two-year results showed that intercropping maize production was higher than that of mono-cropping maize,with an average increase of 18.7%.Intercropping soybean production was lower than that of monoculture soybean,with an average reduction of 31.1%.The composite production of each treatment was higher than that of the two crops.The land equivalence ratio of different intercropping patterns is greater than one.For the intercropping treatments of different intercropping treatments,the average compound yield of 4:2 between the same density was 16961kg·hm^-2,which was the highest,and the average land equivalent ratio was 1.92,reaching the maximum value.The 4:2 intercropping has a greater yield advantage than other intercropping models.3.Corn?soybean promoted the absorption of crop nitrogen.The results of two years showed that the soil nitrogen content of 0-80 cm soil intercropping maize was lower than mono-cropping,intercropping soybean soil total nitrogen content was higher than mono-cropping;intercropping corn plant total nitrogen content was higher than mono-cropping.During the intercropping seasons of different intercropping treatments,the average soil total nitrogen content of soybeans in the 0 to 80 cm soil under 4:2 was 1.6326 g/kg and 1.8022 g/kg,respectively,reaching the maximum value.The average total nitrogen content of leaves,stems and grains in 4:2intercropping corn plants was the highest among the treatments.Under the 4:2intercropping pattern,the nitrogen fixation of soybean was promoted better,and the4:2 intercropping system was more competitive with nitrogen than other intercropping systems.4.Corn?soybean increased the water use efficiency of corn.The results of two years showed that the water use efficiency of intercropped corn was higher than that of mono-cropping,with an average increase of 12.7%.The intercropping soybean water use efficiency was lower than that of mono-cropping,with an average reduction of 26.6%,and the intercropping water equivalence ratio was greater than 1 with intercropping advantages.Among the intercropping patterns of different intercropping patterns,the water use efficiency of maize and soybean was the highest among 4:2crops,with an average of 27.10 kg·hm²·mm^-1 and 6.08 kg·hm²·mm^-1,and the average water equivalent ratio was 1.98,which was higher than other intercropping.The 4:2intercropping had higher water use efficiency and better intercropping advantages than other intercropping models.5.Corn?soybean increased the photosynthetic rate of intercropping maize and reduced the photosynthetic rate of intercropping soybean.The results showed that the photosynthetic rate of intercropping maize was higher than mono-cropping maize,and the photosynthetic rate of intercropping soybean was lower than that of mono-cropping soybean.The photosynthetic rate of 2:1 intercropped maize was higher than that of other treatments in each period,reaching 37.6?mol/?m²·s?in the big bell-mouth period,reaching a maximum value.The relative chlorophyll content?SPAD?of 2:2 intercropping maize was higher than that of other treatments at all growth stages,reaching a maximum of 62.9 at the grain-filling stage.The lower the number of corn bands in the corn glutinous soybean system,the higher the photosynthetic rate and the SPAD value of the intercropping corn,the canopy structure and the air permeability of the 2:1 intercropping and the 2:2 intercropping can make better use of the light energy.