Effect of Nitrogen Supply on Absorbing Nitrogen Feature and Dry Matter Accumulation of "Double Low" Oilseed Rape

The effect of nitrogen supply on absorbing nitrogen feature and yield of double low oilseed rape was studied by using of pot experiment.Results indicated that,for supplying nitrogen oilseed rapes,their nitrogen accumulation amounts quickly increased from seedling to later stage of stem enlongation,while declined from later stage of stem enlongation to later flowing stage,increased after flowing stage,which does not still exceeded nitrogen accumulation amounts of later stage of stem enlongation.The same change tendency was found in treatments without nitrogen supply,however,the change intensity was obviously less than those of supplying nitrogen treatments,and nitrogen accumulation amount at later flowing stage exceeded that of later stem enlongation stage.Whether supplying nitrogen or not,nitrogen amounts of nutritive organs continuously decreased with plant growing,reproductive organ nitrogen amounts of plant with supplying nitrogen also continuously decreased,nitrogen amounts of that without supplying nitrogen was shaped in a single peak curve.The time of dry matter accumulation maximum rate of oilseed rape without supplying nitrogen appeared earlier than that with supplying nitrogen,while nitrogen physiological efficiency of oilseed rape with nitrogen supplying was highest at siliquing period,that without nitrogen supplying at later period of flowing.For this reason,nitrogen supplying could obviously increased plant nitrogen accumulation amount,nitrogen content of plant,biomass and seed yield,but decreased nitrogen physiological efficiency.