秸秆炭化还田对热带土壤-水稻体系氨挥发的影响

氨挥发是稻田氮肥的主要损失途径之一。作为改良土壤和提高农业可持续性发展的优良农艺措施,秸秆炭化还田对氨挥发减排具有良好的效果。本研究通过土柱试验,设置不施氮肥(ON)、单施化肥(CT)、施用生物炭(BI)、生物炭+化肥(CBI)、添加秸秆(ST)、秸秆+化肥(CST)6个处理,研究了水稻秸秆直接还田和炭化还田对热带土壤-水稻体系氨挥发的影响。结果表明:与秸秆直接还田相比,炭化还田降低了稻田氨挥发排放通量和累积氨挥发量;与CT相比,CBI处理的累积氨挥发量减少了4.1%。这主要是因为生物炭具有独特的理化性质,可通过吸附降低田面水中铵态氮(NH₄⁺-N)的浓度。秸秆炭化还田是控制热带水稻种植系统氨挥发、减少农业面源污染的有效途径。

Effects of staw-derived biochar on ammonia volatilization in tropical soil-rice system

Ammonia volatilization is one of the main pathways of nitrogen loss in rice field. As a practical agronomic measure to improve soil quality and agricultural sustainability, the application of straw-derived biochar may effectively reduce ammonia volatilization emission. In this study, six treatments including no nitrogen fertilization (ON), only chemical fertilizer (CT), biochar (BI), biochar+chemical fertilizer (CBI), straw (ST) and straw+chemical fertilizer (CST) were set up in the soil column experiment to study the effects of direct returning and carbonized returning of rice straw on ammonia volatilization in tropical soil-rice system. The results showed that compared with straw direct returning to the field, biochar application reduced ammonia volatilization flux and accumulated ammonia volatilization amount in the rice field. Compared with CT, CBI treatment resulted in a 4.1% reduction in accumulated ammonia volatilization amount, mainly due to biochar’s unique physic-chemical properties, which decreased the concentration of soil ammonium nitrogen (NH₄⁺-N) through adsorption. Therefore, application of straw-derived biochar is an effective way to control ammonia volatilization and to reduce agricultural non-point source pollution in tropical soil-rice system.