Effects of Conservation Tillage on Soil Microbial Biomass and Activity

27 Mar Effects of Conservation Tillage on Soil Microbial Biomass and Activity

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Abstract

研究保护性耕作对土壤微生物特性的影响对于土壤管理具有重要意义。试验研究了保护性耕作对麦田土壤微生物量碳、 活跃微生物量、土壤呼吸、呼吸商的影响。 前 3项采用的方法分别是:基质诱导呼吸法、呼吸曲线数学分析法和 CO2释放量法。 结果表明, 保护性耕作土壤微生物量碳 0 ～ 10 cm土层大于 10 ～ 20 cm土层, 而常规耕作两土层间无明显差异。 秸秆还田在播 种前、越冬期和起身期能显著提高土壤微生物量碳, 而开花期和收获期则降低土壤微生物量碳。 少耕还田 10 ～ 20 cm土层微生 物具有较强的养分调控作用。 保护性耕作利于 0 ～ 10 cm土层活跃微生物量的提高。 秸秆还田和保护性耕作在耕作作业初期 (越冬期和起身期)能增强土壤呼吸速率;在耕作作业后期(开花期和收获期 )能显著降低土壤呼吸速率。 免耕秸秆覆盖在 10 ～ 20 cm土层呼吸商较高, 而常规耕作无秸秆还田在 0 ～ 10 cm土层呼吸商较高。 土壤微生物量碳和呼吸商是衡量土壤微生物特 性的重要指标。

English Abstract

The study of the effects of conservation tillage on soil microbial characteristics is important for soil management. The effects of conservation tillage on soil microbial carbon, active microbial load, soil respiration and respiration quotient in wheat fields were studied. The first three methods were substrate-induced respiration, mathematical analysis of respiration curves and CO2 release quotient. The results showed that the microbial amount of soil carbon in 0-10 cm soil layer was greater than that in 10-20 cm soil layer, but there was no significant difference between the two layers in conventional tillage. The results showed that the soil microbial amount of carbon was significantly increased at the pre-planting, overwintering and rising stages, but decreased at the flowering and harvesting stages. The microorganisms in the 10-20 cm soil layer in the less tilled field had strong nutrient control effects. Protective tillage improves the microbial activity in the 0-10 cm layer of soil. Straw return and conservation tillage enhanced soil respiration rate at the beginning of tillage (wintering and rising) and significantly reduced it at the end of tillage (flowering and harvest). The respiration quotient (RQ) was higher in the 10-20 cm soil layer with no-till straw, whereas it was higher in the 0-10 cm soil layer with conventional tillage without straw. Soil microbial carbon and respiratory quotient (RQ) were important indicators of soil microbial properties.