Effects of Nitrogen Application Rate on Cotton Yield Formation and Nitrogen Utilization Efficiency under Rape-Cotton Double Cropping Straw Returning Condition
Based on the rape-cotton double cropping model,in order to explore the effects of nitrogen application rate on cotton yield and nitrogen absorption and utilization under the condition of rape and cotton straw returning,six treatments were set,T1 was no straw returning+N 180 kg/ha;T2-T6 refered to nitrogen application of 0,60,120,180 and 240 kg/ha on the basis of straw returning.The results showed that under the condition of straw returning to the field,nitrogen application could improve the leaf area index at flowering and boll stage,thereby improving the population photosynthetic performance of cotton,and further improving the dry matter accumulation of cotton plants.The boll number and boll weight and other yield traits,seed cotton yield were the highest under the nitrogen application level of 180 kg/ha.The agronomic utilization rate and recovery rate of nitrogen fertilizer decreased with the increase of nitrogen application rate,and decreased significantly when the nitrogen application rate were 120 and 180 kg/ha,respectively.Under the same nitrogen application rate(180 kg/ha),compared with no straw return,straw returning increased the yield of seed cotton by 7.7％,and significantly improving the agronomic and physiological utilization rates of nitrogen fertilizer.Based on the growth and development of cotton and the absorption and utilization of nitrogen,under the condition of full returning of rape and cotton straw in the rape-cotton rotation system,the input of fertilizer nitrogen in cotton field can be reduced appropriately,and 120-180 kg/ha was appropriate.
NETL
NSTL
万方数据
