紫云英翻压对水田土壤可溶性有机氮及生化性质的影响

Effect of Addition of Chinese Milk Vetch(Astragalus sinicus L.)on Soil Soluble Organic Nitrogen and Biochemical Properties in Paddy Soil

以亚热带红泥砂田为研究对象,在15℃和25℃条件下,利用淹水培养法模拟水田土壤紫云英翻压还田,研究其对土壤可溶性有机氮(SON)、酶活性及微生物量碳、氮的影响。结果表明:15℃和25℃条件下翻压紫云英后土壤SON含量总体呈先上升后下降并趋于平稳的变化规律,分别于培养15 d和10 d达到峰值,比未翻压紫云英处理提高138.11%和84.20%。两种温度条件下翻压紫云英均显著提高土壤SON含量、脲酶、蛋白酶和谷氨酰胺酶活性以及微生物量碳和氮。土壤SON含量与脲酶、蛋白酶、谷氨酰胺酶、微生物量碳和氮呈显著或极显著正相关。翻压紫云英后水田土壤SON的迁移及其环境风险应引起充分关注。

In order to determine th e characteristics of soluble organic nitrogen（SON） and microbial biochemistry responding to the application of Chinese milk vetch, addition of Chinese milk vetch was simulated by waterlogged incubation experiment with subtropical red mud sand field at 15 ℃ and 25 ℃. The results indicated that addition of Chinese milk vetch at different temperatures could significantly increase soil SON content in the short term and in the whole culture period. The content of soil SON immediately increased and rapidly returned to background level. The contents of soil SON reached peak at 10 d and 15 d after addition of Chinese milk vetch treatments, which were138.11% and 84.20% higher than that without addition treatment at 15 ℃ and 25 ℃. Addition of Chinese milk vetch in both temperature conditions could also significantly increase the activities of soil urease, protease and glutamine, as well as the contents of microbial biomass carbon and nitrogen. There were significant positive correlations between soil SON and microbial characteristics such as urease, protease, glutamine and the contents microbial biomass carbon and nitrogen. These results imply that addition of Chinese milk vetch could significantly increase soil SON content in waterlogged condition, and the migration and environmental risk of SON in paddy soil should be attracted full attention after addition of milk vetch.