不同收获时期对油菜机械收获损失率及籽粒品质的影响

以华油杂62为材料，测定70%油菜角果变黄至角果明显炸裂时期机械收获的产量损失、植株不同部位水分含量、粒重和籽粒含油量等指标，研究不同收c获时期对产量损失率和籽粒品质的影响。试验表明，机械收获的产量总损失率在7.00%~15.80%之间，随着收获时期逐渐推迟，总损失率先降低后增加。产量损失分为自然脱粒损失、割台损失和清选脱粒损失。割台损失率随收获时期推迟逐渐增加，占总损失率的比例为7.80%~31.01%；清选和脱粒损失率随收获时期推迟逐渐降低，是机械收获中最大的损失部分，占总损失率的56.87%~92.20%。总损失率与籽粒、角果皮、主花序和分枝水分含量均呈极显著正相关。籽粒水分含量为16.23%时千粒重和含油率最高，而后，随籽粒水分含量的下降，千粒重、含油率、全碳含量和C/N值均略有降低。油菜机械化收获以籽粒和角果皮水分含量在11%~13%之间时为宜，此期的千粒重、油分含量、机械收获产量和产油量均较高。

Effects of Harvesting Date on Yield Loss Percentage of Mechanical Harvesting and Seed Quality in Rapeseed

A field experiment was conducted at different harvesting periods ranging from 70% pod yellow to pod shattering significantly using a variety Huayouza 62 in 2012—2013. The yield loss, moisture content and seed quality were measured. The results showed that the total yield loss percentage ranged from 7.00% to 15.80% at different harvesting periods, and in the process of harvesting the total yield loss percentage decreased firstly and then increased. The total yield loss in mechanical harvesting was composed of the yield loss caused by shattering (SL), yield loss caused by combine header (CHL) and yield loss caused by cleaning and threshing (CTL). The percentage of CHL increased with lasting the harvesting date, and the ratio of CHL to the total yield loss ranged from 7.80% to 31.01%. Among them the percentage of CTL was the largest, which decreased with lasting the harvesting date, and the ratio of CTL to the total yield loss accounting for 56.87% to 92.90%. The total yield loss percentage had very significant and positive correlation with moisture contents of seed, shell, main inflorescence and branches. When the seed moisture content was 16.23%, the 1000-seed weight and oil content were the highest. With decreasing the seed moisture content further, 1000-seed weight, oil content, carbon content and C/N ratio decreased slightly. The period of mechanical harvesting with the seed or pod shell moisture content from 11% to 13% was suitable for getting relatively high 1000-seed weight, oil content, mechanical harvesting yield and oil yield.