生石灰施用增加了酸性双季稻田氮素氨挥发损失

选择南方典型酸性双季稻田,采用通气法研究了不同生石灰用量对稻田氨挥发通量、田面水NH_4~+-N浓度和pH值的影响。结果表明:撒施生石灰显著影响稻田田面水NH_4~+-N浓度和pH值,生石灰用量与田面水NH_4~+-N浓度和田面水pH值之间均存在极显著正相关关系;撒施生石灰,显著增加稻田氮素氨挥发损失,早、晚稻季氨挥发损失量较不施生石灰处理分别增加2.20~22.91和3.08~52.44 kg/hm~2,增幅分别达19.28%~200.79%和6.96%~118.48%;当早、晚稻季分别施纯氮150和180 kg/hm~2时,撒施生石灰450~3 750 kg/hm~2,氨挥发损失量分别达13.61~34.32和47.34~96.70 kg/hm2,氮素损失率分别达7.44%~18.78%和21.66%~44.24%;当早、晚稻季生石灰用量分别超过900和1 800 kg/hm2时,稻田氨挥发显著增加。

Application of Quick Lime to Promoting Ammonia Volatilization Loss in Acidic Double- Cropping Rice Field

Typical double cropping rice acidic field in southern China and venting method were used in this study on dynamic changes of ammonia nitrogen (NH4+-N) concentration, pH value and ammonia volatilization in treatments with different quicklime application amount. The results showed that broadcasting quicklime affected NH4+-N concentration and pH value significantly, the NH4+-N concentration and pH value in surface water of paddy filed were significantly positively correlated with quicklime application amount. Broadcasting quicklime was significantly increased nitrogen ammonia volatilization losses in the paddy fields. The total amount of ammonia volatilization loss was increased by 2.20-22.91 kg/hm2 and 3.08-52.44 kg/hm2, 19.28%-200.79% and 6.96%-118.48%, respectively, compared with non-quicklime treatment in early and late rice seasons. Broadcasting quicklime at 450-3750 kg/hm2 led to ammonia volatilization loss at 13.61-34.32 kg/hm2 and 47.34-96.70 kg/hm2 or the nitrogen loss rate at 7.44%-18.78% and 21.66%-44.24%, respectively, as 150 and 180 kg N/hm2 was used in early and late rice seasons, respectively. The ammonia volatilization increased significantly when the amount of quicklime application was over 900 kg/hm2 and 1800 kg/hm2 in early and late seasons, respectively.