氮施用量对夏玉米土壤水氮动态及水肥利用效率的影响

采用田间小区试验,监测夏玉米不同生长期土壤水分和硝态氮剖面含量变化,研究不同施氮量对其时空变化及籽粒产量、水肥利用效率的影响,探讨氮肥对水肥资源高效利用的调节作用。结果表明：不同施氮处理,土壤剖面水分和硝态氮随土壤深度的变化趋势基本一致,即表层50 cm土壤水分和硝态氮含量较高且呈降低态,50-110 cm相对较低且波动较小,灌浆期二者均达到最低值;各生长期表层50 cm土壤含水量呈不施氮处理均高于施氮处理,50-110 cm土层则相反;施氮能提高土壤硝态氮含量,土壤硝态氮运移受土壤水分状况和含量的影响,含量越高,向下移动越深;施氮能显著提高水分利用效率及籽粒产量,增产效果明显（增产28.52%-37.86%）,二者均以施氮240 kg/hm^2处理最高;随施氮量的增加籽粒产量及籽粒吸氮量和水分利用效率增幅均表现为先升高后降低之趋势,当施氮量超过240 kg/hm^2后,籽粒产量和水分利用效率提高并不显著;不施氮与施氮处理氮素生产力、氮肥利用率之间均存在极显著差异。在本试验条件下,从控制土壤硝态氮积累及取得较高的产量和氮素利用率综合考虑,夏玉米的适宜施氮量范围应控制在120-240 kg/hm^2较好。

Influence of nitrogen application on soil moisture-nitrogen dynamics and water-fertilizer use efficiency of Zea mays

A field experiment was carried out to study the influence of applying nitrogen(N)-fertilizer on soil moisture,soil nitrate N(NO^-₃-N) distribution and accumulation amounts in soil profile,grain yield,water use efficiency(WUE),and nitrogen use efficiency(NUE) of Zea mays during different growth periods. The results show that variation of soil moisture and NO^-₃-N concentration in soil profile with soil depth show similar changes under different amount of N-fertilizer,namely soil moisture and NO^-₃-N in the 50 cm topsoil has a larger variation range than that did in the 50-110 cm,both of this reach lowest value in grouting stage.During different growth periods,soil water content(SWC) without nitrogen fertilizer application(NFA) is more than that with NFA in 50 cm topsoil,on the contrary,in 50-110 cm soil depth.Applicating N increased NO^-₃-N content significantly.Translocation of NO^-₃-N is affected by soil water content and NO^-₃-N content,the higher of the content the deeper movement in the soil.NFA could improve sharply WUE and grain yield(increase 28.52%-37.86%),the situation reach the summit at 240 kg/hm² of NFA.Whit the N application rates enhance,grain yield and amount of N uptake by grain shows increased at first and then decreased,when applying N-fertilizer exceeded 240 kg/hm²,grain yield and WUE increase not significantly.N productivity and NUE have very significant between NFA and without NFA.Under this experiment conditions,results suggested that the optimal effect on boosting its yield,WUE,NUE and controlling soil NO^-₃-N accumulation for Zea mays happened with 120-240 kg/hm² of NFA.