The relationship between activity of soil microorganisms and soil matric suction was studied. The concept of bubbling suction, which is the soil matric suction at which air permeability of soils becomes non-zero, was applied. The objective of this experiment was to test the hypothesis that highest microbial activity in soil occurs when soil matric suction is slightly larger than the bubbling suction because both water and oxygen are abundant. In all the three soils tested, the highest microbial respiration was observed at soil matric suctions just larger than the bubbling suction. The microbial activity at small matric suction reached the highest value slower than that around bubbling suction.%研究了土壤微生物活性与土壤基膜吸力的关系,将土壤发泡点,即土壤导气率由0突变为非0时的基质吸力,与微生物的最高呼吸活性相联系,试图证明土壤微生物的最高活性发生于略高于土壤发泡点的基模吸力.对粗沙土、细沙土和砂壤土三种轻质地土壤的测定表明,土壤微生物的最高呼吸活性发生在略高于土壤发泡吸力的基质吸力.土壤基模吸力较小时微生物活性到达最高值的速度较慢,土壤基模吸力在发泡点附近时,微生物活性到达最高值的速度较快.
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