长期施肥对红壤旱地土壤活性有机碳和酶活性的影响

以江西进贤长期肥料定位试验为平台,研究了红壤旱地不同施肥措施对土壤微生物生物量、活性有机C、C库管理指数以及土壤酶活性的影响。研究结果表明:与不施肥和单施化肥土壤相比,施有机肥处理土壤的pH、CEC、有机C、全N、全P、无机N、速效P、速效K及土壤微生物生物量均显著增加,土壤活性有机C和C库管理指数也较试前土壤和其他处理土壤明显提高,此外,土壤的转化酶、脱氢酶、脲酶和酸性磷酸酶活性也较其他处理显著增加。土壤微生物生物量、活性有机C以及4种土壤酶活性之间的相关关系显著,且它们均与土壤有机C、全N、全P、无机N、速效P等土壤养分呈显著正相关。因此,红壤旱地通过长期施用有机肥或与无机肥配施,不仅能显著提高土壤有机质的数量和质量,而且能增加土壤微生物生物量和酶活性,从而显著提高土壤肥力和土壤持续生产力。

Effects of long-term fertilization on soil active organic carbon and soil enzyme activities in upland red soils

Soil fertility is important for the sustainable development of red soil agroecosystem. In this paper, soil microbial biomass, soil active organic carbon, carbon management index (CMI) and soil enzymes activities were studied in upland soils under different fertilizer applications in a 21a long-term fertilization experiment. Results showed that soil pH, CEC, SOC, total N, total P, mineral N, available P, available K and soil microbial biomass in manure fertilization treatments (NPK+OM and OM) all increased significantly compared with no fertilization (CK) and mineral fertilization treatments (N, P, K, NP, NK, NPK and 2NPK). The active organic carbon and carbon management index also significantly increased and more than the original soil and other fertilization treatments. Furthermore, the soil invertase, dehydrogenase, urease and acid phosphatase activities were all significantly higher than those in other fertilization treatments. There were significant correlations between soil microbial biomass, active organic carbon and the four soil enzymes activities, and these soil microbial properties were all positively correlated with soil pH, SOC, total N, total P, mineral N and available P except for the correlations between soil invertase, phosphatase and soil pH. So, manure application or co-application of manure and mineral fertilizers not only increased the quantity and quality of soil organic matter, but also enhanced significantly soil microbial biomass and soil enzymes activities, thus could improve red soil fertility and soil sustainable productivity.