氮肥对黄籽双低杂交油菜菌核病的影响

试验结果表明,不同施氮量间病株率和病情指数差异均极显著;施氮量300～375kg/hm^2与0～225kg/hm^2的处理间病株率差异显著和极显著,病情指数差异极显著.病株率和病情指数以施氮量375kg/hm^2的处理最高,平均为15.19%和13.21,不施氮的处理最低,平均为7.04%和4.62.菌核病危害造成减产,施氮量0～375 kg/hm^2的处理产量损失率平均为3.56%～18.29%;施氮量、病株率、病情指数、产量损失率间呈极显著正相关.甘蓝型黄籽双低杂交油菜适宜施氮（纯N）量为150～225 kg/hm^2,菌核病危害较轻,能获得高产3000kg/hm^2以上.

Effects of Amount of Applied Nitrogen on Sclerotinia sclerotiorim of Yellow Seed with Double Low Hybrid Rape (Brassica napus)

The results showed that there was very significant difference in diseased plant rate and diseasedness index between different amount of applied nitrogen and there was significant difference and very significant difference in diseased plant rate and diseasedness index between amount of applied nitrogen of 300-375kg/ha and 0-225kg/ha. The diseased plant rate and diseasedness index were up to 15.19% and 13.21 respectively under 375kg/ha of applied nitrogen and the diseased plant rate and diseasedness index were 7.04% and 4.62 respectively under 0kg/ha of applied nitrogen. There was very significant positive correlation between amount of applied nitrogen and diseased plant rate, diseasedness index and percentage of yield damage. When amount of applied nitrogen was from 0 to 375kg/ha, the percentage of yield damage was from 3. 56%-18. 29% because of Sclerotinia sclerotiorim. The 150-225 kg/ha of applied nitrogen is suitable for yellow seed with double low hybrid rape and its maximum yield can reach over 3000kg/ha.