| Fresh maize-fresh soybean strip intercropping is a kind of economic and efficient planting mode which is a intensive utilization of land,ecology,resources.The bandwidth and density arrangement play an important role in crop growth and population yield benefits in the fresh maize-fresh soybean strip intercropping system.In this experiment,fresh maize-fresh soybean strip intercropping was used as the object,and two kinds of fresh maize varieties with large difference in plant height were used as materials,the two factors split-plot design was adopted,in 2018,the main-plot factor A was the bandwidth,A1:200cm,A2:240cm,the sub-plot factor B was the density,B1:37500 plants/hm2,B2:45000 plants/hm2,B3:52500 plants/hm2;in2019,on the basis of the first year,further optimized the density level and removed minimum density,and increased the upper limit of the density design to 60000plants/hm2.Through the analysis of the effects of bandwidth and density arrangement on the population yield benefits,dry matter accumulation and distribution,grain formation and commodity quality of the fresh maize-fresh soybean strip intercropping system,we hope to provide theoretical guidance for the high yield,high quality,high efficiency cultivation of fresh maize-fresh soybean strip intercropping.The main research results are as follows:1.Effects of bandwidth and density on dry matter accumulation,distribution and transport in strip intercropping systemWith the increase of bandwidth,the dry matter accumulation of the two kinds of fresh maize decreased after anthesis.The dry matter accumulation of each organ and the distribution proportion of dry matter to the grain of fresh soybean increased,under the bandwidth of 240cm,the dry matter accumulation of soybean grains intercropped with tall stalk and dwarf stalk varieties increased by 26.22%and 21.74%compared with 200cm,and the dry matter accumulation of the intercropping population decreased;while the density increased,dry matter accumulation after anthesis,dry matter translocation rate and contribution rate of vegetative organs to grains of two kinds of fresh maize varieties increased first and then decreased,the density of 52500plants/hm2 reached the maximum value.compared with other densities,the average increase of dry matter translocation rate of vegetative organs of tall and dwarf stalk varieties was 7.09%-14.60%and 6.38%-16.96%respectively.The dry matter accumulation of each organ of fresh soybean decreased with the increase of maize density,and the dry matter accumulation of intercropping population reached the peak value at 52500 plants/hm2.The interaction between bandwidth and density was not significant,for two kinds of varieties under the two bandwidths,the condition of52500 plants/hm2 density is conductive to the dry matter accumulation and translocation of fresh maize and obtain a higher population accumulation amount.2.Effects of bandwidth and density on grain formation in strip intercropping systemWith the increase of bandwidth and density,the number of fertilized florets of two kinds of fresh maize varieties decreased,which led to the decrease of floret fertilization rate,the increase of seed abortion rate and total abortion rate.When the density is more than 52500 plants/hm2,The seed abortion rate of fresh maize increased greatly.The abortion of tall stalk maize among varieties is more affected by density.The number of unfertilized florets and the increase of seed abortion after fertilization are the main reason for the decrease of the final number of grains per ear with the increase of bandwidth and density of fresh maize.With the increase of bandwidth from 200cm to 240cm,the active grain-filling period of tall and dwarf stalk maize varieties were shortened by 3.11 days and 1.75days respectively,while the growth mass achieving the maximal grain-filling rate of tall and dwarf stalk maize varieties were decreased by 16.95%and 7.15%respectively.With the increase of density,the active grain-filling period of tall and dwarf stalk maize varieties were shortened by 2.62-4.84 days and 1.74-3.39 days on average,and the growth mass achieving the maximal grain-filling rate of tall and dwarf stalk maize varieties were decreased by 13.45%-27.11%,11.52%-20.38%on average;The grain-weight increment and grain-filling rate of fresh soybean at each stage also decreased with the increase of corn density,however,the increased bandwidth alleviated the shading of fresh soybean by maize and improved the ability of grain filling.Path analysis and correlation analysis showed that the main factors affecting the 100-kernel weight of the tall stalk maize varieties were the active grain-filling period and maximum grain-filling rate,while the main factors affecting the100-kernel weight of the dwarf stalk maize varieties were growth mass achieving the maximal grain-filling rate and maximum grain-filling rate,the grain weight of fresh soybean depended on the grain-filling rate.3.Effects of bandwidth and density on the population yield of fresh maize-fresh soybean strip intercropping systemWith the increase of bandwidth,the yield of two kinds of fresh maize varieties decreased significantly.under the bandwidth of 240cm,the yield of tall and dwarf stalk maize varieties decreased by 6.24%and 5.62%on average compared with that of 200cm,while the yield of fresh soybean increased significantly with the increase of maize bandwidth,moreover,the effect of increasing soybean yield intercropping with tall stalk varieties is more obvious.Under different bandwidth,the yield of two kinds of fresh maize varieties reached the maximum under the density of 52500 plants/hm2,the average yield increase of tall stalk and dwarf stalk maize varieties at this density were 8.79%-15.36%and 7.24%-21.48%respectively;the interaction of bandwidth and density had no significant effect on the yield,and the intercropping population yield was mainly affected by the fresh maize yield,the yield of fresh maize and population yield of the two kinds of varieties were the highest in the 200cm bandwidth and 52500 plants/hm2.According to the regression equation fitting,the maximum yield of dwarf stalk maize varieties was 13563.84kg/hm2,and that of tall stalk maize varieties was 16816.68kg/hm2,the bandwidth and density combinations that reached the maximum yield were 200cm,52653 plants/hm2 and 200cm,49898plants/hm2 respectively.4.Effects of bandwidth and density on the quality of fresh maize-fresh soybean strip intercropping systemIncreased bandwidth and density led to the barren tip of fresh maize grew longer,the ear became thinner,the single spike weight,the one-level ear rate and bract rate decreased,and maize ear uniformity became worse,the one-level ear rate was an important index to affect the economic benefits of fresh maize,with the increase of bandwidth,the one-level ear rate of tall stalk and dwarf stalk maize varieties decreased by 11.76%and 25.78%on average,with the increase of density,the one-level ear rate of tall stalk and dwarf stalk maize varieties decreased by18.82%-34.80%and 31.25%-44.51%;The two-pod rate and three-pod rate of fresh soybean intercropped with different maize varieties decreased with the increase of maize density,but expanding the bandwidth can increase the two-pod rate and three-pod rate and improve the commodity of pod.5.Comprehensive evaluation of population yield benefits in strip intercroppingThe principal component analysis method and DTOPSIS method were used to comprehensively evaluate the yield and commodity quality of the fresh maize-fresh soybean strip intercropping system under different bandwidth and density arrangement.Under different analysis methods for two years,the dwarf stalk maize varieties-fresh soybean strip intercropping was treated with 200cm,52500 plants/hm2,while the tall stalk maize varieties-fresh soybean strip intercropping was treated with200cm,45000 plants/hm2 with the highest evaluation score,the yield and quality characters were close to ideal solution,the comprehensive characteristic performed well.Under this combination of bandwidth and density,the economic benefits of intercropping population of dwarf and tall stalk varieties reached the maximum value,which could reach 84400 yuan/hm2 and 100900 yuan/hm2 respectively.In summary,on the basis of considering the population yield,commodity quality and economic benefits of the fresh maize-fresh soybean strip intercropping system,the optimal bandwidth and density arrangement of tall stalk fresh maize variety-fresh soybean strip intercropping are 200cm,45000 plants/hm2,the optimal bandwidth and density arrangement of dwarf stalk fresh maize variety-fresh soybean strip intercropping are 200cm,52500 plants/hm2.From the perspective of appropriately increasing the bandwidth to facilitate mechanized operation,the bandwidth can be increased to 240cm,the suitable density of tall stalk maize variety is still 45000plants/hm2,and that of dwarf stalk maize variety is still 52500 plants/hm2. |
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