播种深度和种子大小对大豆出苗率和幼苗生长的影响

播种深度和种子大小对种苗建成的影响一直是种子学研究中的热点问题。以大豆种子为试验材料，研究播种深度和种子大小对大豆出苗率和幼苗生长的影响。试验选用2个大豆品种的种子，分为大、中、小3种粒级，播种深度为5 cm、10 cm、15 cm。调查出苗速度、出苗率和幼苗的主要性状。结果表明，5 cm、10 cm和15 cm深度的种子出土时间分别需要6~13天、9~17天和13~23天；最终出苗率与室内发芽率相比，3种深度依次减少7%、34%和80%；幼苗长度和幼苗干重随着种子深度的增加逐渐减少，差异达到极显著水平(P<0.01)；种根长度与幼苗长度的表现相反，根干重在10 cm深度时最高，显著(P<0.05)高于5 cm和15 cm的干重；种子大小对种苗生长也有一定的影响，大、中粒种子的田间出苗率极显著高于小粒种子(P<0.01)；幼苗长度和幼苗干重随着种子的增大而增加达到显著水平(P<0.05)，甚至大粒种子与小粒种子之间达到极显著水平(P<0.01)。

Effects of Sowing Depth and Seed Size on Seedling Emergence Percentage and Seedling Growth in Soybean

The effects of sowing depth and seed size on seedling establishment were focus issue at the seed science all the while. Soybean seed was tested in this paper by compare the seedling emergence percentage and seedling growth in the different sowing depth and seed size in the field. Seed of two varieties in soybean were divided artificially into three kinds of grain with big, middle and small size. These seed were sowed in depths of 5 cm, 10 cm and 15 cm in the field, respectively, and the seedling emergence time, percentage and main seedling characters were survey in the test. The results that the seedling emergence time was prolonged in the field, 6 d-13 d, 9 d-17 d and 13 d-23 d were needed by seedling emergence in 5 cm, 10 cm and 15 cm depth, respectively. Compared with indoor test, the final seedling emergence percentage in the field were decreased 7%, 34% and 80% in 5 cm, 10 cm and 15 cm depth, respectively. The seedling length and dry seedling weight were gradually reduced with sowing depth and shown a very significant difference (p < 0.01); Contrarily, root length was the longest in 15 cm depth and was the shortest in 5 cm depth. The dry root weight in 10 cm depth was heavy more than in 5 cm and 15 cm depth and shown significant difference (p < 0.05). Seedling growth was also affected by seed size. Both big and middle size was higher in seedling emergence percentage than small size with very significant difference (p < 0.01). The seedling length and dry weight gradually increased with seed size and shown significant difference (p < 0.05) among three seed size and vary significant difference (p < 0.01) between big and small size.