Rochette Philippe, Macdonald J Douglas, Angers Denis A, Chantigny Martin H, Gasser Marc-Olivier, Bertrand Normand
Agriculture and Agri-Food Canada, 2560 Hochelaga Blvd., Québec City, QC, Canada, G1V 2J3.
J Environ Qual. 2009 May 20;38(4):1383-90. doi: 10.2134/jeq2008.0295. Print 2009 Jul-Aug.
Volatilization of ammonia following application of urea contributes to smog formation and degradation of natural ecosystems. The objective of this study was to evaluate the impact of (i) incorporation and banding of urea and (ii) surface broadcast of slow-release urea types on NH(3) volatilization in a dry acidic soil. Volatilization was measured using wind tunnels for 25 d after standard urea (140 kg N ha(-1)) was broadcast, broadcast and incorporated (0-5 cm), or incorporated in shallow bands (3-5 cm) to a conventionally tilled silty loam soil. Urea supplemented with a urease inhibitor or coated with a polymer was also broadcast at the soil surface. Little N diffused out of the polymer-coated granules and ammonia losses were low (4% of applied N). Use of a urease inhibitor also resulted in a low NH(3) loss (5% of applied N) while maintaining soil mineral N at levels similar to plots where untreated urea was broadcast. The rate of hydrolysis of urea broadcast at the soil surface was slowed by the lack of moisture and NH(3) loss (9% applied N) was the lowest of all treatments with standard urea. Incorporation of broadcast urea increased emissions (16% applied N) by increasing urea hydrolysis relative to surface application. Furthermore, incorporation in band also increased emissions (27% applied N) due to a localized increase in soil pH from 6.0 to 8.7. We conclude that incorporating urea in bands in a dry acidic soil can increase NH(3) volatilization compared to broadcast application followed by incorporation.
施用尿素后氨的挥发会导致烟雾形成和自然生态系统退化。本研究的目的是评估（i）尿素的混入和条施以及（ii）缓释尿素类型的撒施对干旱酸性土壤中氨挥发的影响。在将标准尿素（140 kg N ha⁻¹）撒施、撒施并混入（0 - 5厘米）或条施于传统耕作的粉质壤土后，使用风洞测量25天内的氨挥发情况。添加脲酶抑制剂或用聚合物包膜的尿素也在土壤表面撒施。聚合物包膜颗粒中很少有氮扩散出来，氨损失较低（占施氮量的4%）。使用脲酶抑制剂也导致氨损失较低（占施氮量的5%），同时使土壤矿质氮水平与撒施未处理尿素的地块相似。由于缺乏水分，土壤表面撒施的尿素水解速率减慢，氨损失（占施氮量的9%）是所有标准尿素处理中最低的。与表面撒施后再混入相比，混入撒施的尿素会因尿素水解增加而使排放量增加（占施氮量的16%）。此外，条施也会增加排放量（占施氮量的27%），因为局部土壤pH值从6.0升高到8.7。我们得出结论，在干旱酸性土壤中条施尿素与撒施后再混入相比，会增加氨的挥发。
