Effects Of Different Intercropping Ratios On Photosynthetic Characteristics And Yield Of Maize And Soybean

Intercropping can enhance light capture and absorption through interspecific complementation,which is one of the important measures to improve crop yield and land resource utilization.However,the traditional intercropping mode is not suitable for the whole mechanization of modern agriculture.In order to improve resource utilization rate and land yield rate,it is of great significance to study the corn-soybean intercropping mode suitable for mechanized production and seek the appropriate proportion,which is of great significance to achieve high and stable yield and increase efficiency in agriculture.In this study,maize monocropping（M）,soybean monocropping（S）,maize||soybean row ratio 2:4 intercropping（M2S4）,maize||soybean row ratio 4:4 intercropping（M4S4）,maize||soybean row ratio 4:6intercropping（M4S6）,five treatments were conducted to explore the effects of different intercropping ratios on photosynthetic characteristics,population yield,economic output value and land equivalent ratio of maize and soybean,providing theoretical basis for the optimization of maize and soybean intercropping pattern.The main results are as follows:1.Compared with mono cropping,maize plant height in different proportions of maize and soybean intercropping decreased to different degrees,and the order from high to low was M>M4S4>M4S6>M2S4,which decreased by 3.37%,4.86%and 8.04%compared with mono cropping,respectively.At the same time,intercropping increased soybean plant height in different degrees,and the order from high to low was M4S4>M4S6>M2S4>S,which increased by 31.77%,29.69%and 29.60%compared with mono cropping,respectively.2.During R1 and R5 period,the dry matter weight of maize organs in all treatments（except male ear dry weight in R5 period,but male ear dry weight in intercropping was still higher than that in monoculturing）increased,and the difference between intercropping and monoculturing was significant（P<0.05）.The order of dry matter weight of maize organs in different treatments was as follows:M2S4>M4S4>M4S6>M,indicating that intercropping was beneficial to dry matter accumulation.In R2 and R6 period,soybean dry weight increased in overground,underground and root,but significantly lower in intercropping than that in mono-cropping.The order of soybean dry weight from high to low was S>M2S4>M4S4>M4S6,indicating that intercropping was not beneficial to the accumulation of soybean dry matter,and gradually decreased with the increase of shading degree.3.With the advance of growth,photosynthetic physiological indexes of maize in R5 stage decreased due to maize leaf senescence,lower than that in R1 stage,but intercropping was still higher than that in monoculcropping maize M,effectively delaying maize senescence.The order from high to low was:M2S4>M4S4>M4S6>M,and M2S4 treatment had the best photosynthetic effect.In R2 and R6 period,photosynthetic rate（Pn）（except M2S4 treatment）,stomatal conductance（Gs）and transpiration rate（Tr）of soybean were significantly（P<0.05）lower than those of monocultural treatment,with the same trend,and the order from high to low was as follows:S>M2S4>M4S4>M4S6,and the change of intercellular CO₂ concentration showed the opposite pattern in different growth stages:M4S4>M4S6>M2S4>S.4.Compared with monocropping,intercropping significantly（P<0.05）increased the ear weight,row number per ear,row number of grains,grain weight per ear and 100-grain weight,and increased the yield in the corn zone.Intercropping increased the number of nodes in main stem,pods per plant and grains per plant,but decreased the grain weight per plant and 100-grain weight,and decreased the yield in soybean zone.The order of composite yield from high to low was M>M4S4>M4S6>M2S4>S.At the same time,LER values of intercropping were all greater than 1.M4S4 treatment had the most advantage with LER value of 1.26,followed by M2S4 and M4S6 with LER value of 1.18 and 1.11,respectively.Considering the factors of local government subsidies,the economic output value of each treatment in descending order is M4S4>M2S4>M4S6>M>S,of which M4S4 treatment has the most potential to increase production and has the prospect of promotion.