黑土-春小麦中三种化学氮肥的去向

FATE OF THREE NITROGEN FERTILIZERS APPLIED TO A BLACK SOIL GROWING SPRING WHEAT

用15N田间微区试验研究了黑土－春小麦中作基肥施用的尿素、碳铵和硝酸钾三种氮肥的氮素去向。试验设在黑龙江省海伦市郊区，氮肥用量为纯N75kg／hm2，施肥深度为10cm。结果表明，硝酸钾和尿素的氮素利用率相当，分别为58．4％和55．9％，显著高于碳铵（42．6％）。硝酸钾在土壤中的残留率（28．7％）显著低于碳铵（38．8％）和尿素（38．2％）。氮素总损失在5．8％～186％之间；碳铵的损失显著大于尿素，硝酸钾的损失则介于之间（12．9％）。氮肥的激发效应较弱，三种氮肥的表现激发量都不高。试验结果还表明，小麦吸收的氮素中来自肥料氮的比例约为1／3，而以土壤来源氮为主。

Fate of urea, ammonium bicarbonate and potassium nitrate applied to a black soil growing spring wheat was inveshgated by the 15N tracer technique and microplot in the field. The experiment was conducted in suburbs of Hailun city, Heilongjiang Province. Nitrogen fertilizer at a rate of N 75 kg / hm2 was deeply placed in 10 cm soil layer.Results showed that deep placement is an effective measure to decrease nitrogen loss and increase the efficiency of fertilizers N utilization in spring wheat-black soil system. The plant recoveries of potassium nitrate (58.4%) and urea (55.9%) were comparable, and significantly higher than that of ammonium bicarbonate (42.6%). The residual N in soil from applied potassium nitrate (28.7%) was significantly lower than urea (38.2%) and ammonium bicarbonate (38.8%). The total nitrogen losses for the three sources of N fertilizers were in the range of 5.8%-18.6% with the lowest from urea and the highest from ammonitum bicarbonate. The priming effect of N fertilizers applied to the black soil was rather low. Results also showed that about 1/3 of the N taken up by wheat was derived from the applied N fertilizers and 2/3 from soil.