缓释尿素对滴灌玉米农田土壤无机氮及产量的影响

通过研究不同基施比例的缓释尿素与滴灌玉米土壤氮素供应、氮素吸收利用以及农田氮素平衡的相互关系,明确缓释尿素在滴灌玉米上作基肥施用并探讨其施用的适宜基施比例。结果表明,基施缓释尿素对比普通尿素增加了土壤硝态氮和铵态氮含量,缓释尿素处理土壤无机氮积累量表现为富集现象,不施氮处理则表现为负积累效应;土壤氮素含量随基施比例的增加而降低。玉米产量、氮肥利用率和农学效率随缓释尿素基施比例的增大表现为先增加后降低的趋势,土壤氮素表观损失量和氮素盈余量随基施比例的增大均先降后增。以缓释尿素50%作基肥的玉米产量及氮肥利用率较高,土壤氮素表观损失量较低。

Effect of Slow-release Urea on Soil Inorganic N and the Yield of Maize under Drip Irrigation

The objective of this field experiment was to determine the effect of slow-release urea on the soil N supply, maize yield, N uptake, N use efficiency, and N balance, and to confirm the optimum application rate of slow-release urea should be applied to drip-irrigated maize. The result showed that slow-release urea increased residual NO₃^--N and NH₄⁺-N concentrations. Soil inorganic N content increased when N fertilizer was applied to the soil but declined when no N fertilizer was applied. Residual soil N was significantly greater in the fertilized treatments than in the unfertilized treatment. Maize yield, N efficiency and agronomy efficiency decreased when 20% of the N fertilizer was applied as slow release fertilizer at planting, but increased when 50% of the N fertilizer was applied as slow release fertilizer at planting. Apparent N loss and the N surplus were both significantly less when 50% of the N was applied as slow-release urea at planting compared with 20% of the N. The results indicated that maize yield and N use efficiency were high and soil N loss was low when 50% of the N fertilizer was applied as slow-release urea as planting.