Study On Maize-soybean Intercropping Model And Soybean Growth Characteristic Suitable For Central And Southern Liaoning

In this experiment,the shade-tolerant soybean and dense-planting maize varieties with large planting area selected by our research group were used to conduct maize-soybean intercropping experiments according to the ecological conditions of different regions.Liaodou 32 soybean varieties and Dongdan 6531 maize varieties were selected as experimental materials in Liaozhong District of Shenyang City;Tiefeng 31 soybean varieties and Liangyu 99 maize varieties were selected in Pulandian City;Shennong 17 soybean varieties and Dongdan 6531 maize varieties were selected in Xinmin City.The light interception and photosynthetic characteristics of soybean canopy,nutrient content of soybean plant,yield and comprehensive benefits of maize-soybean intercropping were studied under different intercropping patterns.The experiment adopted a completely randomized block design.There were four intercropping patterns: 2 rows of corn //2 rows of soybeans,2 rows of corn //3 rows of soybeans,2 rows of corn //4 rows of soybeans and 2 rows of corn //5 rows of soybeans,and the planting direction is north-south.The main results are as follows:1.Corn,soybean intercropping mode,corn shade to different growth period of soybean plant morphological characters have a direct impact,intercropping soybean in order to obtain more light energy,will lead to plant becomes high,main stem and branch number and section number decreases,internode length become larger,higher balance,with the increase of soybean lines than,these indicators tend to CK(was)normal level gradually.Moreover,the intercropping soybean plant height was affected the most in R3(pod bearing stage).At the same time,compared with CK,the distribution of pod seeds in the canopy of intercropped soybean will decline under the influence of maize shading.2.Under different maize-soybean intercropping patterns,the shading effect of maize resulted in the suppression of soybean light energy capacity.With the increase of row ratio of soybean planting,the photosynthetic capacity of soybean leaves increased gradually.In the 2:5 intercropping mode,the photosynthetic capacity of soybean was the strongest and the growth was the best,but it was lower than CK level.2:2 Intercropping mode had the greatest influence on Maize shading,and the photosynthetic capacity of soybean leaves was the weakest.The trends of net photosynthetic rate(Pn),stomatal conductance(Gs)and transpiration rate(Tr)were the same;the trends of intercellular CO2 concentration(Ci)were contrary to those of net photosynthetic rate(Pn),stomatal conductance(Gs)and transpiration rate(Tr).Maize shading reduced leaf area index(LAI)of soybean,but increased light absorption of intercropped soybean.3.Under different maize-soybean intercropping patterns,with the advancement of soybean growth period,the percentage of nitrogen,phosphorus and potassium in soybean plants increased gradually and the change trend was the same,showing the fastest growth rate in R3-R6 stage,but lower than CK level.As soybeans mature,they transfer nutrients from the vegetative to the reproductive organs.Among all intercropping modes,the 2:3 intercropping mode is the most ideal maize-soybean intercropping mode.4.With the increase of row-to-row ratio,the number of pods per plant,seeds per plant,pods per grain and grain weight per plant of soybean intercropping showed a gradual upward trend,and the 2:5 intercropping pattern was only inferior to CK level.Intercropping did not affect the 100-grain weight of soybean.The shading effect of corn increased the protein content of soybean,but had no significant effect on the fat content of soybean.5.The total yield of intercropping was higher than that of monoculture soybean and lower than that of monoculture corn.With the increase of soybean planting row ratio,the corn yield was gradually reduced,while the soybean yield was gradually increased,and the total yield showed a decreasing trend,namely,the total yield of the 2:2 intercropping mode was the highest,195.30%--247.72% higher than the single-cropping soybean yield;the total yield of the 2:5 intercropping mode was the lowest,32.58%--37.02% lower than the single-cropping corn yield,and 111.54%--146.18% higher than the single-cropping soybean yield.From the perspective of comprehensive benefits(1.6 yuan /kg for corn and 3.7 yuan /kg for soybean),the comprehensive benefits of 2:5 intercropping mode were the lowest,34.93%--57.88% higher than that of mono-cropping soybean;the comprehensive benefits of 2:3 intercropping mode were the highest,6.19%--7.34% higher than that of mono-cropping corn,49.75%--79.50% higher than that of mono-cropping soybean.