施氮量对冬小麦氮素吸收利用、土壤中硝态氮积累和籽粒产量的影响

为通过控制施氮量来实现高肥力条件下小麦的高产、高效、安全生产提供依据,以冬小麦品种‘藁8901’为材料,研究了高肥力条件下不同施氮水平对小麦氮素吸收利用、籽粒产量和土壤中硝态氮含量的影响。试验结果表明:在高肥力条件下,随着施氮量的增加,冬小麦的籽粒产量和植株吸氮量均是先增加后降低,籽粒产量和植株吸氮量均以N150最高,氮素生产力则以N0最高。在冬小麦的拔节期和成熟期,土壤NO3-N含量均随着施氮量的增加而增加,减少氮肥施入量能降低冬小麦拔节期和成熟期土壤0-100 cm土层中的硝态氮含量。施用氮肥能提高小麦拔节期和成熟期植株全氮积累量和土壤NO3-N积累量,但两者并非同步增加,土壤NO3-N积累量增加的幅度远远大于植株全氮积累量的增长幅度。在施氮量0-180 kg/hm2范围内时,植株全氮积累量有所增加,且土壤中硝态氮的积累量增加较为缓和;而在施氮量180 kg/hm2的基础上继续提高氮素用量,植株全氮积累量下降,而土壤硝态氮积累量却开始大幅度增加。据此综合考虑,冬小麦‘藁8901’的适宜施氮量应控制在150 kg/hm2左右。

Effect of nitrogen application rate on nitrogen absorption,NO3-N accumulation in soil and grain yield of winter wheat

Nitrogen fertilizer application was very important to wheat production.In order to clarify the effect of nitrogen fertilizer on nitrogen absorption,NO3-N accumulation in soil and grain yield of winter wheat,a field experiment was conducted with a winter wheat cultivar ‘Gao 8901’ in Gaocheng County,Hebei Province,during 2004-2005.The experiment was arranged by randomized block design,including six treatments of N 0,150,180,210,240 and 270 kg/hm2(expressed in N0,N150,N180,N210,N240 and N270 respectively) with three repeats.The results showed that,in high fertility conditions,with the increase of nitrogen application,the grain yield and N uptake of winter wheat were all increased in the beginning,and decreased thereafter.The highest grain yield and the highest nitrogen absorption were all achieved for the treatment N150,while the highest nitrogen productivity was achieved for the treatment N0.At stem elongation stage and maturity stage,the NO3-N content in soil increased with the increase of nitrogen application amount;the reduction of nitrogen fertilizer application could decrease the NO3-N content in soil within 0～100 cm depth.At stem elongation stage and maturity stage,the accumulation amounts of total N in wheat plants and NO3-N in soil profile were all increased with the increase of nitrogen application amount.However,the increase of the two parameters above were not simultaneously,the increment of soil NO3-N accumulation was much higher than that of total N accumulation in wheat plants.In the scope of nitrogen application of N 0～180 kg/hm2,the total N accumulation in wheat plants increased,and the accumulation of soil NO3-N increased moderately.Supplied with more than N 180 kg/hm2,however,the total N accumulation in wheat plants decreased,while soil NO3-N accumulation increased rapidly.According to the results above,the suitable amount of nitrogen fertilizer application of the winter wheat cultivar ‘Gao 8901’ should be about 150 kg/hm2.