ABSTRACT

Soil microbial processes can serve as sensitive indicators of soil quality. A 2-year field experiment was conducted to determine the combined effects of tillage (conventional, CT; reduced, RT; and no tillage, NT) and residue (with or without residue removal) on soil microbial and enzyme activities under wheat (Triticum aestivum L.)- and corn (Zea mays L.) in a rotation, using a split-plot design with three replications near Shiraz, Iran. The highest microbial biomass (660.19 and 667.00 µg MBC g⁻¹ soil in wheat and corn, respectively) was recorded under RT. Soil respiration was affected by tillage in order NT > RT > CT. The lowest microbial quotient (qCO₂) was obtained under RT (15.60 in wheat and 5.94 in corn, respectively), while NT and CT either showed similar effects or NT was superior over CT. The highest acid phosphatase enzyme was obtained under RT (442.65 and 374.17 µg PNP g⁻¹ soil h⁻¹ in wheat and corn, respectively). Alkaline phosphatase and urease enzymes were highest under NT. Our research has shown that replacing CT with conservation tillage (especially RT) can greatly improve soil enzymes and microbial biomass and optimize qCO₂ values under wheat- and corn in a rotation in a short term.

摘要

土壤微生物过程可以作为土壤质量的敏感指标。进行了一项为期 2 年的田间试验，以确定耕作（常规，CT；减少，RT；和免耕，NT）和残留物（去除或不去除残留物）对小麦土壤微生物和酶活性的综合影响（Triticum aestivum L.)- 和玉米 ( Zea mays L.) 轮作，在伊朗设拉子附近使用具有三个重复的裂区设计。在 RT 下记录了最高的微生物生物量（小麦和玉米中分别为660.19 和 667.00 µg MBC g ^{-1土壤）。}耕作对土壤呼吸的影响顺序为 NT > RT > CT。最低微生物商 (qCO ₂) 在 RT 下获得（小麦分别为 15.60，玉米分别为 5.94），而 NT 和 CT 要么显示出相似的效果，要么 NT 优于 CT。在 RT 下获得最高的酸性磷酸酶（小麦和玉米中分别为 442.65 和 374.17 µg PNP g ^-1土壤 h ^-1）。NT下碱性磷酸酶和脲酶最高。我们的研究表明，用保护性耕作（尤其是RT）代替CT可以在短期内大大提高土壤酶和微生物量，优化小麦和玉米的qCO _2值。