不同利用年限菜地土壤有机碳矿化动态和酶活性变化

通过田间采样分析并结合室内培育试验,观测了不同利用年限菜地土壤有机碳矿化和酶活性变化特征。结果表明,蔬菜地土壤由于大量化肥的施用,导致NO3--N的积累。即使大量施用有机肥,NO3--N的积累也较明显。随着利用年限延长,培养前期的菜地土壤有机碳矿化率有下降趋势;脲酶和转化酶活性下降,磷酸酶活性因大量P肥使用造成P的积累而呈上升趋势。土壤磷酸酶和转化酶活性与土壤有机C和全N含量呈显著相关关系。不同利用年限菜地土壤酶活性变化幅度较大,能够更为敏感的指示土壤质量的变化。

Soil Organic Carbon Mineralization and Enzyme Activity in Soils Different in Duration of Vegetable Plantation

Through indoor analysis and incubation of soil samples collected from fields in the Yangtze Delta region, differences in soil organic carbon mineralization and enzyme activities between soils different in duration of vegetable plantation were observed. Findings showed that NO3--N content in the soils increased significantly with the duration because of application of large amounts of chemical fertilizer or/and organic manure. Mineralization rate of soil organic carbon, during the early period of incubation, decreased with the increase in duration. Activities of soil urease and invertase also decreased with the increase in duration, while soil phosphatase increased owing to phosphorus accumulation in the soil from application of large amounts of phosphate fertilizer. Soil phosphatase and invertase activities were significantly correlated to soil organic carbon and total nitrogen content. Soil enzyme activity varied obviously with duration of vegetable plantation and could be cited as a sensitive indicator of changes in soil quality.