The Research On The Cause Of Yield Increase Under The Condition Of Root Pruning & Top Removal Grow-Seedlings & Transplant In Soybean

Four cultivate forms were adopted in this experiment. Comparison was made on their yields and the cause of yield increase among the different cultivate forms; aimed at Root pruning & Top removal at the same time, three different genotypes soybeans were adopted to investigate the yield of different genotypes soybean and the cause of yield increase, providing theoretical evidence for practical production. The results of this experiment showed that: 1. The yield of soybean was different among four cultivate , so was the yield among genotypes. The order of yield about different cultivate forms was Root pruning & Top removal > Ground-covers > Root pruning & Top unremoval > direct seeding; When root pruning & Top removal and ground-covers were compared with direct seeding, the result of yield both were significance at 1% level, the yield of soybean has already attained ideal effect of yield increase on the Root pruning & Top removal cultivate form. The order of yield was heinong40> dongnong92-19> kelong No.1 among different genotypes soybean. Comparing Heinong4o with KeLong No.1, the result of yield also attained significance at 1% level. 2. The elements of constituting yield were not same among different cultivate forms, so were among different genotypes soybean1 Particularly the number pods of every plant were affected significantly. Among four cultivate forms, root pruning & Top removal were higher than the others conspicuously. Under the root pruning & Top removal, the number pods of every plant of Heinong40 was the highest. 3. During the whole growth period, dry matter accumulation appeared curve. Comparing with different cultivate forms, the total dry matter accumulation of root pruning & Top removal was the highest. Under the cultivate forms, among genotypes soybean, the total dry matter accumulation on Heinong 40 was the highest. 4. The distribution rate of dry matter showed that: During the whole growth period, the distribution rate of dry matter in leaves decreased gradually. The decreasing rang was discrepancy about different cultivate forms and genotypes soybean. Among four cultivate forms, the distribution rate of dry matter in leaves were same level in the earlier growth period1 in the later growth period, the distribution rate was the lowest about the cultivate form of Root pruning & Top removal. Under the cultivate form of Root pruning & Top removal, comparing with the three genotypes soybean, the distribution rate of Heinong 40 was the lowest. The distribution rate of dry matter in stem increased in the earlier period, and in the later period decreased.On the Root pruning & Top removal cultivate forms and on Heinong40soybean, the rang of the distribution rate in stem risen and fallen were the greatest. The distribution rate of dry matter in pod increased, the same as in leaves and stems, on the Root pruning & Top removal and heinong4o, the rising rang were the greatest. 5. The Leaf area index (LAI) increased in the earlier growth period and decreased in the later growth period, and the LAI was the highest at seed-filling period. The LAI of the Root pruning & Top removal and Heinong40 were the highest. 6. The Crop Growth Rate (CGR) increased in the earlier growth period and decreased in the later growth period; The Net Assimilation Rate (NAR) decreased in the earlier growth period1 in the middle and later growth period increased or decreased. The CGR and NAR of Root pruning & Top removal among four cultivate forms was the highest; the records showed that Heinong40 was the highest among different genotypes soybean.