用^(15)N示踪法研究不同土壤水分条件下小麦对氮的吸收利用

NITROGEN UPTAKE AND FERTILIZER NITROGEN USE EFFICIENCY OF WHEAT UNDER DIFFERENT SOIL WATER CONDITIONS

本研究结果表明，同一施氮量处理小麦地上生物量、茎叶产量和籽粒产量随土壤水分含量的增加而提高，在同一土壤含水量下，这３ 种产量则随氮素肥料施用量的增加而增加。小麦成熟后地上部吸收总氮量的方差分析显示出施氮处理和水分处理对小麦吸氮量的影响达到显著水平，同一施氮处理小麦地上部吸氮总量随土壤含水量的增加而增加，在３ 种土壤水分含量条件下，小麦的吸氮量均随施尿素氮肥量的增加而提高。施尿素处理的土壤Ａ 值随土壤含水量的增加而降低；尿素与猪粪配施处理的土壤Ａ 值则随土壤含水量的增加而增加。在相同施肥量下，尿素氮的利用率随土壤含水量的增加而提高，当田间持水量分别为５０ ％ 、７０ ％ 和９０ ％ 时，小麦对土壤中氮素利用率分别为１３３０ ％ 、２７９７ ％ 和３２２６ ％ ，尿素与猪粪配施处理在３ 种土壤水分条件下的氮肥利用率分别为１９９６ ％ 、２９９０ ％ 和３４３９ ％ 。说明在水分缺乏的情况下，尿素氮的利用率受土壤水分条件的制约，土壤水分充足及无机氮肥与有机肥配施可以提高氮肥的利用率。

The pot experiment was conducted to study the effects of soil water regime and fertilizer nitrogen rate on the yields,nitrogen uptake and fertilizer nitrogen utilization of wheat by using 15 N tracer method.The results showed that the aboveground biomass,stem yield and grain yield increased with the increase of soil moisture in the fertilizer nitrogen treatments.All the yield increased with the increase of the fertilizer nitrogen rate in the soil water treatments.It was found that both soil water regime and fertilizer nitrogen rate significantly influenced the amount of nitrogen uptake by wheat according to the variance analysis.The amount of nitrogen uptake increased with the rise of the soil moisture in fertilizer nitrogen treatments and the amount also increased with the increase of the urea nitrogen rate in the soil water regime.Soil water regimes not only had an impact on nitrogen uptake but also had a close relationship with soil nitrogen supply and fertilizer nitrogen use efficiency.The soil A values decreased in urea treatment and increased with the rise of the soil moisture in the combination treatment of urea with pig manure.The fertilizer nitrogen use efficiency rose with the rise of the soil moisture in the same fertilizer nitrogen treatment.The fertilizer nitrogen use efficiency of the urea treatment was 13\^3%,27\^9% and 32\^3% in the soils with 50%,70%and 90% of the field water capacity,respectively.The fertilizer nitrogen use efficiency in the combination treatment of urea with pig manure was 20\^0%,29\^9%and 34\^4% in the soils of above three levels,respectively.It was concluded that the low soil moisture restricted urea nitrogen use efficiency(UNUE) and the UNUE could be raised by combination treatment of urea with manure in the soil of enough moisture.\;