带籽紫云英翻耕对水稻产量及稻田土壤性质的影响

【目的】研究带籽紫云英作为绿肥对稻田土壤性质的影响，为推进绿肥生产和农田可持续利用提供依据。【方法】开展3年田间定位试验，第一年设置4个不同紫云英翻压量（2.81，5.61，8.42，11.23 t/ha）处理，无紫云英翻压作对照处理，后两年均延续上一年试验结果，每年水稻移栽前将各小区田面自然长出的带籽紫云英测产后直接翻耕；测定水稻产量及稻田土壤养分、生物学性质以及水稳性团聚体等指标。【结果】紫云英带籽翻耕的绿肥处理可使水稻有效穗及产量显著增加，并增加土壤中的有机酸，同时土壤磷酸酶、蔗糖酶和过氧化氢酶等活性均明显提高；土壤水溶性有机碳随绿肥施用量增加而升高，但过多绿肥施用量会抑制土壤微生物量碳；土壤由大团聚体和微团聚体向中微团聚体富集。【结论】带籽紫云英作为绿肥施用能起到改善土壤理化性质和生物学性质，稳步提高土壤肥力，显著增加水稻产量的作用，水稻移栽前翻压量以不超过8.42 t/ha（干重）为宜。

Effects of Astragalus sinicus ploughed at maturity stage on rice yield and soil properties of paddy field

【Objective】The effects of Astragalus sinicus ploughed at maturity stage as green manure on paddy soil properties were studied to provide references for advancing the production of green manure and sustainable development of field. 【Method】A three-year field positioning experiment was carried out. In the first year,five different levels（0,2.81, 5.61,8.42,11.23 t/ha） of Astragalus sinicus ploughed at maturity stage were designed. And in the next two years,the amounts of Astragalus sinicus at maturity stage ploughed were based on the natural growth amounts of Astragalus sinicus at maturity stage of the year in each plot field. The yields of Astragalus sinicus at maturity stage were estimated and ploughed directly before rice transplanting. Rice yield,soil nutrients,biological properties and water-stable aggregates of paddy fields were measured as well. 【Result】The effective panicles and rice yields increased significantly after ploughing Astragalus sinicus at maturity stage. Meanwhile,the organic acid content in paddy field increased and the activities of soil phosphatases,invertase and catalase were higher. The soil dissolved organic carbon also increased with the increasing application of green manure. However,excess amount of green manure inhibited the soil microbial biomass carbon content. The macro aggregates and micro aggregates richened closer to middle aggregates. 【Conclusion】 As green manure,the use of Astragalus sinicus at maturity stage could improve soil physicochemical and biological properties,boost soil fertility and increase rice yield significantly. But the ploughing amount of Astragalus sinicus at maturity stage before rice transplanting should be less than 8.42 t/ha （dry weight）.