Effect of Density on Leaf Area Index,Dry Matter Accumulation and Distribution in Soybean Population

Five planting density of Kennong 4 were set,plants were sampled at V4,R1,R3,R5,R6 stage and the change law of leaf area index(LAI) and dry matter(DM) accumulation and distribution in five soybean populations were determined.LAI increased with the increase of planting density at a certain range.LAI at R5 stage concentrated in the upper and middle canopy.DM phase accumulation,daily accumulation and of total accumulation showed a single peak curve.DM phase accumulation increased with increase of planting density and daily accumulation decreased with increase of planting density.Whole plant,stem,leaf,petiole and pod weight of unit area increased with the increase of planting density.Dry weight at R5 stage concentrated in the bottom and middle canopy,and the center of dry weight increased with the increase of planting density.The pods number,seeds number and seed weight of single plant increased as the the density decreased.The planting density had significant effects on leaf area index and dry matter accumulation and distribution and yield.The yield was the highest at the planting density of 3.6×1055 plants·ha-1.