Effects Of Different Densities On Growth Of Root And Formation Of Flowers And Pods Of Spring Soybean

The experiment aims at exploring the relationship between the growth of root growth,the formation of flowers and pods,the photosynthesis,the dry-matter accumulation and the yield of high-yield spring soybean under different planting densities.In this paper,the high-yield varieties of "Xin dadou 27" and "Xin dadou 8" were adopted as experimental materials,three planting densities including 21×104 plants·ha-1(D1),30×104 plants·ha-1(D2)and 48×104 plants·ha-1(D3)were arranged in the field,the vertical distribution of soybean root system was investigated by "trench sampling method",the process of flowering and podding was recorded by "marking observation method",the parameters like root growth,photosynthesis,dry-matter accumulation and formation of flowers and pods were measured systematically,moreover,the yield and yield components were analyzed.Finally,the main results are as follows:1.With the increasing planting density,the dry weight of roots in the treatment soil layer of 0-20-40cm firstly increased and then decreased,and the total dry weight of roots of plants group was the largest before and after pod filling,and then gradually decreased;in addition,the changes of total root length of different treatments showed the same trend,namely firstly increased and then decreased,reaching the maximum around the initial podding stage,and the difference was significant during the growth period.2.With the increasing planting density,the number of flowers,pods and chambers of each plant decreased significantly,but the number of total flowers,pods and chambers of plants group increased significantly,moreover,the difference between treatments was significant.With the development of growth process,the number of new flowers and new pods of each plant per day firstly increased and then decreased;in addition,the increasing density delayed the peak time of flowering and podding,shortened the flowering period,but the number of flowers of plants group per day firstly increased and then decreased with time lapse.3.With the increasing density,there was a positive correlation between total root dry weight,total root length and total flowers and total chambers of two varieties,but the correlation between total root length and total flowers and total cambers was more significantly than that between total root dry weight and total flowers and total chambers.4.During the growth period,the leaf area index of each treatment of the two varieties firstly increased and then decreased,moreover,increased gradually with the increase of density.As time goes,the leaf net photosynthetic rate of each canopy firstly increased and then decreased,and the net photosynthetic rate decreased with the increase of density;in addition,with the increasing density,the dry-matter accumulation per plant decreased,but that of plants group increased,and the difference between treatments was significant.5.Increased density grain yield increased significantly,treatment between the performance of D3>D2>D1.Higher planting densities should be appropriately used in Xinjiang to obtain higher yields.6.The increasing density increased the total root amount and length,the leaf area and dry matter accumulation,the total flowers and pods,and ultimately increased yield.