Relationship Between Soybean Material Distribution, Nutrient Translocation And Yield Formation Under Different Densitie

By setting different planting densities of soybean,the material distribution rule and nutrient transport capacity of soybean biomass were studied to match the objective needs of soybean growth and development,and the biological potential of soybean production and quality improvement was explored.In this study,24 soybean germplasm were used as experimental materials,two soybean yield types were selected based on the yield differences of each soybean variety,and the relationship between yield components,biomass accumulation and distribution,and nutrient accumulation and transport of soybeans under low,medium and high density treatment was summarized.The purpose is to determine the effects of soybean substance distribution and nutrient transport on soybean yield formation under different density models.The main results are as follows:(1)High density increased plant height and decreased branch number of soybean,but had no significant effect on stem diameter and internode number of soybean.The plant height,stem diameter,internode number and branch number of high yield soybean were higher than those of low yield soybean.Stem diameter(r=0.53,P<0.05),internode number(r=0.28,P<0.05)and branch number(r=0.56,P<0.05)were significantly positively correlated with soybean yield at different densities.(2)With the advance of growth period,the accumulation of soybean biomass was the highest from the end of drumming to maturity,and the biomass of soybean was the highest under the treatment of 240,000 plants per hectare.The bioaccumulation of high-yield soybean was higher than that of low-yield soybean.Under different densities,soybean biomass(r=0.81,P<0.05)was significantly positively correlated with soybean yield.The proportion of stem,leaf and pod dry weight to the whole plant dry weight reached the maximum at seedling stage,flowering stage and maturity stage,respectively.With the increase of density,the proportion of stem dry weight to whole plant dry weight gradually increased,but the proportion of leaf and pod dry weight to whole plant dry weight had no significant change.The proportion of leaf dry weight to whole plant dry weight of high yield soybean was higher than that of low yield soybean in each density treatment and period.(3)The rule of nitrogen and phosphorus content in soybean leaves was flowering stage >drumming stage > maturity stage.The nitrogen and phosphorus contents of soybean leaves reached the maximum under the density treatment of 360,000 and 480,000 plants per hectare,respectively.The leaf nitrogen and phosphorus contents of high yield soybean were higher than those of low yield soybean.With the increase of density,the transfer rates of nitrogen and phosphorus in soybean leaves decreased first and then increased,and the transfer rates of nitrogen and phosphorus in soybean leaves were the lowest under the density treatment of480,000 plants per hectare,and the transfer rates of phosphorus in soybean leaves were the lowest under the density treatment of 600,000 plants per hectare.The nitrogen transfer and transfer rate per plant of high yield soybean were higher than those of low yield soybean under low density,but the opposite was true under high density soybean.The phosphorus transfer per plant of high-yield soybean was higher than that of low-yield soybean,and the phosphorus transfer rate of high-yield soybean was higher than that of low-yield soybean before the density treatment of 600,000 plants per hectare.There was a significant negative correlation between leaf nitrogen transfer rate(r=-0.36,P<0.05)and soybean yield at different densities.(4)The increase of density decreased the pod number,kernel number and yield per plant,and the 100 kernel weight and yield of soybean increased first and then decreased.Under the density treatment of 480,000 plants per hectare,soybean had the maximum yield,and the increase of density decreased the harvest index of high-yield soybean.High yield soybean was higher than low yield soybean in yield,pod number,grain number and harvest index,and lower than low yield soybean in 100 grain weight.At different densities,the number of pods(r=0.65,P<0.05),number of grains(r=0.67,P<0.05)and harvest index(r=0.51,P<0.05)were significantly positively correlated with soybean yield.In summary,the soybean biomass accumulation was the highest and the stem biomass was moderate at the medium density(480,000 plants per hectare),while the transfer volume and transfer rate of nitrogen and phosphorus nutrients in soybean leaves were the lowest at this density,but the soybean yield was the highest.Under different density conditions,the biomass distribution,nutrient accumulation and transfer and yield composition of high-yield soybean were better than those of low-yield soybean.