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以安庆沿江农田不同退耕还湖方式——低坝高网式水产养殖和湿地自然恢复区的湿地土壤为研究对象,并以邻近的水田和旱地土壤作为参照,研究退耕还湖后湿地土壤生物化学性质变化。结果表明,退耕还湖18a(1991～2009年)后,在湿地自然恢复区,湿地土壤(深度为0～30cm)微生物量碳含量、土壤磷酸酶活性和过氧化氢酶活性增大,土壤脲酶活性和蔗糖酶活性减小;由水田退耕18a的湿地亚表层土壤(深度为15～30cm)脲酶活性和表层土壤(深度为0～15cm)过氧化氢酶活性与由旱地退耕18a的湿地无明显差异,由水田退耕18a的湿地表层土壤脲酶活性和亚表层土壤过氧化氢酶活性、表层和亚表层土壤微生物量碳含量、蔗糖酶活性和磷酸酶活性都明显高于由旱地退耕18a的湿地。退耕还湖18a后,进行低坝高网式水产养殖的湿地土壤微生物量碳含量、土壤脲酶活性、蔗糖酶活性和磷酸酶活性减小,而过氧化氢酶活性增大;由水田退耕18a的湿地表层和亚表层土壤微生物量碳含量与由旱地退耕18a的湿地无明显差异,由水田退耕18a的湿地表层和亚表层土壤脲酶活性、表层土壤蔗糖酶活性和亚表层土壤磷酸酶活性明显高于由旱地退耕18a的湿地,而其亚表层土壤蔗糖酶、表层土壤磷酸酶、表层和亚表层土壤过氧化氢酶活性均显著低于由旱地退耕18a的湿地。天然湿地土壤微生物量碳含量、土壤脲酶活性、蔗糖酶活性和磷酸酶活性明显低于已退耕还湖的湿地和参照农田土壤。退耕还湖后,湿地的不同利用方式及其历史利用方式影响湿地土壤生物化学性质;湿地土壤有机质等养分含量和水文条件变化是导致湿地土壤生物化学性质变化的主要原因。
Taking the farmland of Anqing along the different ways of returning farmland to lake - the low dam high net aquaculture and the wetland natural recovery area wetland soil as the research object, and the adjacent paddy field and dryland soil as a reference to study the return of farmland to wetland soil biochemistry Nature changes. The results showed that after returning farmland to lake for 18 years (from 1991 to 2009), the microbial biomass carbon content, soil phosphatase activity and catalase activity increased in wetland natural recovery area and wetland soil (depth 0-30 cm) The activities of urease and the activities of sucrase were decreased. The activity of urease and the activities of catalase in surface soil (0 ~ 15 cm depth) in subsurface soils (depth of 15 ~ 30 cm) The results showed that urease activity and catalase activity in topsoil, surface and subsurfacesoil microbial biomass carbon content, invertase activity and phosphatase activity were both significantly higher than those in the wetland converted from cultivated land to cultivated land for 18 years. After returning farmland to lake for 18 years, the soil microbial biomass carbon content, soil urease activity, invertase activity and phosphatase activity decreased while catalase activity increased in wetland with low net and high net aquaculture. The content of soil microbial biomass carbon in wet and subsurface soils was not significantly different from that in wetland reared from dry land for 18 years. The urease activity, surface soil invertase activity and sub-surface soil phosphatase activity of wetland and subsurface soils evacuated from paddy field for 18a From 18a dry land to wetland, the activity of catalase, surface soil phosphatase, surface and subsurface soil catalase in subsurface soil was significantly lower than that in wetland converted from cultivated land to 18a in dry land. Soil microbial biomass C content, soil urease activity, invertase activity and phosphatase activity in natural wetlands were significantly lower than those in the wetland and reference farmland. After returning farmland to lake, the different ways of wetland utilization and their historical utilization affect the biochemical properties of wetland soil. The changes of nutrient content and hydrological conditions of soil organic matter in wetland soil are the main reasons leading to the change of biochemical properties of wetland soil.