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水田改为经济林、蔬菜地是我国南方地区快速城市化过程中重要的土地利用方式的转变,可引起土壤质量的变化。以浙江省杭州市平原地区水稻田和由水稻田改成的经济林(果树、苗木和桑树)和蔬菜地(包括露天蔬菜地和大棚蔬菜地)为对象,研究了泥质田、青紫泥田和淡涂泥田等3种平原地区分布较为广泛的代表性水稻土改旱种植经济林、露天蔬菜地和大棚蔬菜地后土壤活性有机碳及碳库管理指数的变化。结果表明:水田改旱种植经济林、蔬菜地后,表层(0~15 cm)土壤有机碳明显下降,亚表层(15~30 cm)土壤有机碳轻微下降,30 cm以下土壤有机碳基本不变。与长期种植水稻的水田土壤相比,大棚蔬菜地、露天蔬菜地和经济林地表层土壤有机碳分别下降了32.4%~35.7%、28.2%~30.4%和18.3%~24.2%。种植经济林、露天蔬菜地、大棚蔬菜地后土壤活性有机碳(包括易氧化有机碳、颗粒态有机碳、轻组分有机碳、水溶性有机碳和微生物生物量碳)比长期种植水稻的水田有不同程度降低,其中易氧化有机碳、颗粒态有机碳和轻组分有机碳下降幅度大于有机碳总量;与长期种植水稻的水田土壤相比,经济林地土壤颗粒态有机碳和轻组分有机碳分别下降了31.41%~37.09%和22.72%~25.70%;露天蔬菜地土壤分别下降了45.78%~52.36%和39.50%~45.25%;大棚蔬菜地分别下降了55.44%~63.59%和45.92%~55.13%。同时,易氧化有机碳、颗粒态有机碳和轻组分有机碳占总有机碳的比例也有明显的下降趋势。改旱后土壤碳库管理指数呈明显下降,下降幅度:大棚蔬菜地>露天蔬菜地>经济林地。分析认为,土地利用方式改变引起有机碳矿化及有机物质输入平衡发生变化是引起土壤有机碳变化的主要原因;水田改旱不利于土壤碳库管理指数提高。
Paddy field into economic forest, vegetable land is an important land use change in rapid urbanization in southern China, can cause changes in soil quality. Taking paddy fields in the plain of Hangzhou, Zhejiang Province and economic forests (fruit trees, seedlings and mulberry trees) and vegetable fields (including open vegetable fields and greenhouses) transformed from paddy fields as the research object, Muddy fields and other three kinds of plain areas of the more widely distributed representative of the paddy soil to dry planting economic forests, open-air vegetable fields and greenhouse vegetable soils active carbon and carbon pool management index changes. The results showed that the soil organic carbon in the surface layer (0 ~ 15 cm) decreased significantly after paddy field was planted with economic forest and vegetable land, while that in the subsurface layer (15 ~ 30 cm) decreased slightly. Soil organic carbon below 30 cm remained almost unchanged. Compared with the paddy soil with long-term cultivation of rice, soil organic carbon decreased by 32.4% -35.7%, 28.2% -30.4% and 18.3% -24.2% in vegetable land, open vegetable land and surface layer of economic forest respectively. Soil active organic carbon (including readily oxidizable organic carbon, particulate organic carbon, light fraction organic carbon, water-soluble organic carbon and microbial biomass carbon) after planting economic forest, open vegetable land and greenhouse vegetable land had a significantly higher activity than paddy field The degree of decline of organic carbon, particulate organic carbon and light fraction of organic carbon was larger than that of total organic carbon. Compared with paddy soil with long-term cultivation of rice, particulate organic carbon and light fraction of organic wood Carbon decreased by 31.41% -37.09% and 22.72% -25.70% respectively. The contents of soil in open vegetable fields decreased by 45.78% -52.36% and 39.50% -45.25% respectively, while in greenhouse vegetable fields decreased by 55.44% -63.59% and 45.92% 55.13%. At the same time, the proportions of organic carbon, particulate organic carbon and light organic carbon in total organic carbon also decreased obviously. After the drought, soil carbon stock management index decreased significantly, decreasing range: greenhouse vegetable land> open vegetable land> economic forest land. The analysis shows that the change of land use pattern leads to the change of organic carbon mineralization and the input balance of organic matter, which is the main reason for the change of soil organic carbon.