【摘要】 采用田间采样及室内培养方法,对内蒙古武川县耕地、退耕还灌地和放牧草原3种类型土地土壤微生物各类群的数量分布和层化比率进行了研究。结果表明:在土壤耕作层(0~30cm)土壤微生物数量呈逐层下降趋势,3种类型土地的土壤微生物总数相差不大,3种类型土地土壤微生物层化比率存在明显差异。同时提出了土壤微生物层化比率的概念,并认为土壤微生物层化比率可能是一个比较好的指示动态土壤质量(土壤演替方向)的指标,当一个区域土壤微生物层化比率大于2时,土地一般不会发生退化现象。在研究的3块实验区域中,耕地存在较高的退化风险,退耕还灌地正处于逐步恢复的阶段,放牧草原依然存在逐步退化的趋势。更多还原

【Abstract】 A study was done to reveal the distribution of soil microorganisms and soil microbial stratification ratio which was based on the hypothesize that the degree of stratification of soil microorganism with soil depth,expressed as a ratio,could indicate soil quality or soil ecosystem functioning,in the ecological system at the crossing belt(Wuchuan County) of agriculture and animal husbandry.The results showed that the vertical distribution of total microbial number in 0～30 cm was 0～5 cm>5～12.5 cm>12.5～20 cm>20～30 cm,which decreased along with soil depth;there was no obvious difference in total microbial number among farmland,restored area and grazed grassland;and there was apparent difference in soil microbial stratification ratio among the three areas.And the conclusion of this paper was that soil microbial stratification ratio could be a good indicator of dynamic soil quality(the succeed direction of soil),ratio >2 would be uncommon under degraded conditions.Among the three areas,farmland had high risk of degradation;the restored area was on the procedure of restoration although the soil quality was still very poor;and the grazed grassland also had the risk of degradation but the speed was low.更多还原