播期对大豆生长发育和产量构成因子的影响

本试验对黑龙江省北部第4积温带，不同播期对大豆生长发育，干物质积累，叶面积动态及产量构成因子的影响进行了初步研究。结果表明：晚播生育日数比正常播期缩短，后期单株荚数、粒数、百粒重均低于正常播期，最后导致产是下降；早播由于地温低，有粉种现象，保苗率降低较大，特别是对寒性较差的品种影响更大，单株荚数、单株粒数、百粒重低珩正常播期，大豆产量亦比正确播种明显低。从试验结果看出在本区以5月7日前后播种最为适宜，平均产量比早播高11.8％，比晚播高8.0％。

Preliminary Study on the Effect of Planting Date on Soybean Growth and Yield Components

Experiments were carried out to study the effect of different planting date on soybean growth, dry-matter accumulation，leaf area dynamics and yield components in IV accumulated temperature zone of northern part of Heilongjiang province. The results showed that if we planted soybean later than normal planting date, the pods per plant, seeds per plant and 100-seeds weight would be lower than those planted normally because of shorter growth period. If we planted soybean earlier than normal planting date， there would be less percentage of germination because of low temperature of soil. The pods per plant, seeds per plant and 100-seeds weiyht all lower than those planted normally. From the results we could dran a conclusion that we should plant soybean around May 7 in this region, which would lead to average yield 11.8% higher than those planted earlier and 8.0% higher than those planted later.