有机无机肥长期定位试验土壤小麦季氨挥发损失及其影响因素研究

氨挥发是肥料氮素损失的重要途径之一，损失率因土壤类型、气候条件、肥料用量、施肥时间和方式等不同而存在很大差异。为了筛选提高氮肥利用率的肥料运筹方式，本文利用长期定位试验平台，采用间歇密闭通气法，研究了有机无机肥长期施用条件下小麦季土壤氨挥发损失及其影响因素。结果表明，不同肥料种类和配施强烈地影响着土壤氨挥发，在150kgN·hm^-2用量下小麦季氨挥发损失量以NK和有机肥处理为最高，分别达到17．89和15．70kgN·hm^-2，占氮肥用量的10．47％-11．93％，显著高于NPK、NP和有机无机肥配施（1／20M）处理。土壤氨挥发速率与气温呈显著正相关，基肥施用后灌水可以有效地降低氨挥发损失。NPK肥料平衡施用或者有机无机肥配施可以减少氨挥发损失。

Ammonia Volatilization from Soil as Affected by Long-term Application of Organic Manure and Chemical Fertilizers During Wheat Growing Season

Ammonia （ NH3 ） volatilization is one of the major losses of applied nitrogen fertilizers, which not only results in a loss of economy, but also poses a risk to the environmental ecosystem. The rate of ammonia volatilization following fertilizer application is strongly affected by many factors such as soil properties, temperature as well as type, application time and mode of nitrogen fertilizers. To find optimal management practices for increasing nitrogen use efficiency, a long-term experiment was established in 1989 including seven treatments, i.e. organic manure （ OM ）, half organic manure plus half chemical N fertilizer（ 1/2OM ）, NPK fertilizer（ NPK ）, NK fertilizer（ NK ）, NP fertilizer（NP）, PK fertilizer（ PK ） and control（CK）, six treatments of which were used to monitor ammonia volatilization during the wheat growing season using a continuous air flow enclosure method in the North China plain. The flux of ammonia volatilization was dramatically influenced by fertilizer type and their combination. The highest cumulative amount of ammonia volatilization in treatments NK and OM was 17.89 and 15.70 kg N·hm^-2, respectively, as urea was applied at a rate of 150 kg N·hm^-2, which accounted for 10.47%-11.93% of the N applied and was significantly higher than the values in treatments NPK, NK and 1/2OM. The flux of ammonia volatilization was significantly positively correlated with air temperature. And irrigation following basal fertilization greatly reduced ammonia volatilization. Our study indicates that NPK bal- anced application and combination application of organic manure and chemical N fertilizer could lower ammonia volatilization.