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为更好地理解侵蚀土壤质量变化,该文利用137Cs技术探讨了川中丘陵区紫色土陡坡耕地土壤侵蚀对土壤生物学肥力的影响。结果表明,与无侵蚀的坡地相比,陡坡耕地土壤微生物量碳含量及碱性磷酸酶、蔗糖酶活性分别显著降低41%、44%、17%,土壤生物学肥力退化指数MFDI达-35%。陡坡耕地土壤蔗糖酶活性与137Cs浓度显著正相关(r=0.643,p=0.024),表明蔗糖酶活性随土壤侵蚀强度增大而降低。耕作侵蚀造成的陡坡耕地上坡土壤损失导致土壤微生物量碳含量、碱性磷酸酶、脲酶及蔗糖酶活性最低,而耕作侵蚀造成的陡坡耕地坡底土壤堆积导致这4个微生物特性最高,结果陡坡耕地这些微生物特性的空间变异分别增大2.8、0.8、1.4、4.5倍。紫色土陡坡耕地土壤生物学肥力退化与空间变异性增大在今后的土地管理中应引起关注。
In order to better understand the change of soil erosion quality, this paper uses 137Cs technology to study the influence of soil erosion on the biological fertility of steep slope farmland in the hilly area of central Sichuan. The results showed that soil microbial biomass C, alkaline phosphatase and invertase activities were significantly decreased by 41%, 44% and 17%, respectively, and soil microbial degradation index MFDI was -35% . The soil invertase activity on steep cultivated land was significantly and positively correlated with 137Cs concentration (r = 0.643, p = 0.024), indicating that invertase activity decreased with the increase of soil erosion intensity. Soil erosion caused steep slope uphill soil erosion led to the lowest soil microbial biomass C, alkaline phosphatase, urease and invertase activity lowest, and tillage erosion caused by steep slope soil accumulation led to these four microbial characteristics of the highest steep slope The spatial variability of the characteristics of these microorganisms in cultivated land increased by 2.8, 0.8, 1.4 and 4.5 times respectively. Soil biological degradation and spatial variability of steep sloping arable land in purple soil should pay more attention to in future land management.