施氮量对胡麻干物质积累分配及产量的影响

通过大田试验，研究了施氮量对胡麻干物质积累分配及产量的影响。结果表明，胡麻干物质积累随施氮量增加进程加快。苗期至盛花期、青果期至成熟期干物质积累速率分别随施氮量增加而提高、降低，不同施氮处理最高干物质积累速率均出现在盛花期。胡麻完成干物质积累的时间随施氮量增加而提前，中氮水平干物质积累速率最大。施氮对长生育期胡麻品种干物质分配无明显影响，对短生育期胡麻品种影响较大。合理施氮可有效提高胡麻单株有效果数和千粒质量，单位面积产量与单株干物质量呈显著正相关，氮肥农学效率随施氮量增加而降低。河北省张家口市和内蒙古自治区鄂尔多斯试验区最优施氮量分别为90．00，36．80kg·hm-2，比传统不施氮肥分别增产30．84％，16．84％。

Effect of Nitrogen Application Rate on Dry Matter Accumulation and Distribution of Oil Flax

Field experiments were conducted to investigate the impact of different nitrogen （N） application rate on plant dry matter accumulation and distribution regulation as well as yield of oil flax. Results showed that the dry matter accumulation process accelerated with the increase of N application rate. The dry matter accumulation rate increased during the period from seedling stage to full flowering stage and decreased during the period from young fruit stage to ripping stage with the increase of N application rate. The maximum value of dry matter accumulation rate all appeared at full flowering stage under different N treatments. The dry matter accumulation finished ahead of time with the increase of N application rate. And the dry matter accumulation rate ranked top under middle N growth period oil flax cultivars, level. Applying N significantly influenced the but less obvious to the long growth period ones. dry matter distribution of shot Reasonable N application rate increased available pods and thousand-grain weight. The actual output per unit area was significantly positive with dry matter per plant. N use efficiency declined with the increase of N application rate. The optimal N application rate were 90.0 kg/hm2 in Zhangjiakou area and 36.80 kg/hm2 in Ordos area, respectively, increased oil flax yield by 30.84% and 16.84% compared with zero N application.