氮肥减投条件下膜材料使用对稻田氨挥发排放的影响

氨挥发排放是稻田系统氮损失的主要途径.现有技术多以调控氮肥施用为削减氨挥发排放的技术手段；但由于氮肥投入基数较大且减投不能改变氨挥发途径氮损失比例，氮肥减投后的氨挥发排放仍是限制氮肥利用效率提升的瓶颈.对此，本研究选用满足环境友好和使用便捷的农业废弃物粉末和两性分子物质作为膜材料，配合氮肥施用在田面水表进行多次铺洒，研究膜材料对氨挥发排放过程及排放总量的影响，结合作物生长和氮去向探索膜材料对氨挥发排放的影响机制.连续2 a小区试验发现，膜材料使用可减少水稻种植期氨挥发排放总量的19%~31%，由此减少的氮损失或以矿质态氮形态贮存于土壤或提高了作物氮吸收量.施氮条件下，田面水铵态氮含量和pH以及膜材料使用是影响氨挥发排放的主控因子；氮肥减投后，膜材料使用可进一步削减氨挥发排放.基于不同膜材料对氨挥发排放影响机制差异，应用时，可根据实际生产需求对膜材料进行按需选择.

Effects of Film Materials on Ammonia Volatilization Emissions from a Paddy System After Reducing Nitrogen Fertilizer Application

Ammonia volatilization emissions constitute the main pathway of nitrogen loss from paddy systems. Present control technologies are based on reducing the amount of nitrogen fertilizer applied. However, ratio of nitrogen loss through ammonia volatilization emissions has not changed, and it has become a bottleneck for promoting nitrogen use efficiency. Therefore, in order to study the effects of film materials on ammonia volatilization emissions, a two-year field plot experiment was carried out with agricultural waste powder and amphipathic molecule materials spread on surface water after nitrogen fertilizer application in paddy system. The results showed that film materials could reduce nitrogen loss through ammonia volatilization by 19%-31% in the paddy season, and this part of nitrogen was accumulated in soil or assimilated by paddy tissue. The ammonium concentration and pH in the surface water and film materials were the major control factors of ammonia volatilization emissions with nitrogen fertilizer application. Moreover, further reductions in ammonia volatilization emissions could be achieved by film materials after reducing nitrogen fertilizer application. Differences in the effect mechanisms of the film materials provide flexible options for practical agricultural production to meet demands.