摘要:氨挥发是稻田氮素损失的主要途径之一，探究稻田生态种养模式对稻田土壤氨挥发产生的影响，可为该模式的生态环境效益评价提供理论依据。为评估稻蛙共作模式对水稻-紫云英轮作系统氨挥发的影响，通过开展田间小区试验，采用密闭式间歇抽气法采集氨气，对水稻-紫云英轮作系统的土壤氨挥发及其影响因素进行研究。试验共设置3个处理：空白对照（CK，不施肥，不放蛙）、常规水稻种植模式（CR，施化肥，不放蛙）、稻蛙共作模式（RF，施化肥，放蛙）。结果表明：稻蛙共作模式水稻季氨挥发累积量为47.02 kg·hm-2，占当季施氮量12.9%；其后茬紫云英季的氨挥发累积量为16.27 kg·hm-2；全年轮作系统的氨挥发累积量为63.29 kg·hm-2，较常规水稻种植模式的氨挥发累积量降低15.3%。稻蛙共作模式全年水稻-紫云英轮作系统的氨挥发累积量占施氮量的比例为17.4%，显著低于常规水稻种植模式所占比例（20.5%）。水稻田面水的铵态氮浓度是影响水稻季氨挥发的主要因素，水稻田面水pH、水温、气温、风速等因素的影响次之，随温度上升，水稻田面水铵态氮浓度对氨挥发速率的影响逐渐增大。放蛙对水稻产量、水稻产量构成因素、氮肥利用效率及后茬作物紫云英产量的影响不显著。综上所述，稻蛙共作模式在水稻-紫云英轮作系统中具备一定的氨减排潜力，但该模式对稻田氨挥发影响的长期效应及其影响机理仍需进一步研究。
关键词:水稻-紫云英轮作/
稻蛙共作/
氨挥发/
产量
Abstract:Ammonia (NH3) volatilization is one of the main mechanisms of nitrogen loss in paddy fields. Studying the impact of the ecological cultivation model in paddy fields on ammonia volatilization can provide a theoretical basis for its ecological and environmental benefits. To evaluate the effects of rice-frog cultivation on ammonia volatilization in a rice-Chinese milk vetch (CMV) rotation system, the continuous airflow enclosure method was used to collect ammonia in a field plot experiment to study soil ammonia volatilization and its related factors. The experiment included three treatments: control check (CK, no fertilization, no frogs), conventional rice cultivation (CR, fertilization, no frogs), and rice-frog cultivation (RF, fertilization, frogs released). The results showed that the cumulative amount of ammonia volatilization in the rice-frog cultivation treatment was 47.02 kg·hm-2, accounting for 12.9% of the nitrogen application rate in the current season. The subsequent cumulative amount of ammonia volatilization in the Chinese milk vetch season was 16.27 kg·hm-2. The cumulative ammonia volatilization in the annual rotation system was 63.29 kg·hm-2, which was 15.3% lower than that of conventional rice planting. The cumulative amount of ammonia volatilization produced by rice-frog cultivation in the annual rice-Chinese milk vetch rotation system accounted for 17.4% of the annual nitrogen application, which was significantly lower than that of conventional rice cultivation (20.5%). The ammonium nitrogen concentration in the floodwater was the main factor affecting ammonia volatilization in the rice season, followed by the pH and temperature of the floodwater, air temperature, and wind speed. As the temperature increased, the influence of the ammonium nitrogen concentration in the floodwater on ammonia volatilization increased. Frogs did not affect the rice yield, rice yield components, nitrogen fertilizer efficiency, or Chinese milk vetch yield. Therefore, rice-frog cultivation has the potential to reduce ammonia in the rice-Chinese milk vetch rotation system, but the long-term effects of this model on ammonia volatilization in paddy fields and its mechanisms require further study.
Key words:Rice-Chinese milk vetch (Astragalus sinicus) rotation/
Rice-frog cultivation/
Ammonia volatilization/
Yield
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