Abstract:

The purpose of this study is to determine the effects of sowing time on dry matter accumulation, assimilates transfer before and after anthesis and yield of soybean, and to promote the extension of new soybean varieties with high and stable yield. ‘Hedou 37’ was used as experimental material, and three sowing dates were set on June 5th (D₁), June 15th (D₂) and June 25th (D₃). Logistic curve equation was used to analyze the data. Under D₂ sowing date, the initial time of dry matter rapid accumulation in vegetative organs, reproductive organs and shoot of each plant was the earliest, which was the 35th, 55th and 44th day, respectively. The duration was the longest, which was 28, 28 and 29 days, respectively. The maximum dry matter accumulation rate was 0.78, 0.67 and 1.33 g/(plant·d), respectively, and appeared at the 47th, 68th and 58th day, respectively. The transfer amount of assimilates before anthesis (4.14 g/plant) and after anthesis (12.90 g/plant), the transfer rate of assimilates after anthesis (65.45%) and the contribution rate to grain (75.68%) were the highest, and the yield of soybean was the highest (3322.85 kg/hm ²). The suitable sowing time is beneficial to the full use of light and heat resources, can promote dry matter rapid accumulation and transfer, and ultimately increase soybean grain yield.

Key words: summer soybean, sowing time, dry matter, accumulation and transfer, yield