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土壤微生物生物量碳是稻田土壤有机质最具活性的组分之一,可有效地指示土壤质量状况.为探明亚热带地区不同类型稻田土壤微生物生物量碳的剖面分布特征及其与土壤有机碳及养分的关系,通过选取5种不同母质发育的稻田土壤,采集土壤发生层次分层样品,分析其有机碳、微生物生物量碳以及土壤养分的分布特点.结果表明,土壤有机碳和微生物生物量碳含量均随土壤深度的加深而急剧下降,分别介于2.45～26.19 g.kg-1和4.55～1 691.75 mg.kg-1,以耕作层和犁底层的含量最为丰富.不同母质发育的稻田表层土壤微生物生物量碳含量存在显著差异,以板岩风化物发育的黄泥田Ⅰ最高,河沙泥和红黄泥最低;而有机碳含量却以红黄泥和河沙泥最高,其余几种土壤之间并无明显差异.尽管如此,土壤微生物生物量碳依然受有机碳数量的限制,两者呈显著的正相关关系.土壤微生物商亦随土壤深度的增加而明显降低,不同类型土壤耕作层微生物商以河沙泥(2.11%)和红黄泥(1.37%)相对最低,而板岩风化物发育的黄泥田Ⅰ最高(8.24%),说明河沙泥和红黄泥的底物有效性明显低于黄泥田,这也是河沙泥和红黄泥有机碳含量最高而微生物生物量最低的原因之一.土壤微生物生物量碳含量与土壤全氮、碱解氮和有效磷呈显著的正相关关系,而与土壤速效钾的相关性不明显,说明稻田土壤微生物生物量碳除受有机碳的限制外,还与土壤养分存在较为复杂的关系.
Soil microbial biomass carbon is one of the most active components of soil organic matter in paddy so as to indicate the soil quality status effectively.In order to find out the profile distribution of soil microbial biomass carbon and its relationship with soil organic carbon and soil organic carbon in different types of paddy fields in the subtropical zone, And the relationship between soil organic carbon and microbial biomass carbon in paddy soils of five different parent materials was analyzed.The results showed that soil organic carbon and microbial biomass carbon Content decreased sharply with the deepening of soil depth, ranging from 2.45 to 26.19 g.kg-1 and 4.55-1691.75 mg.kg-1, respectively, and the contents of plow layer and plow were the most abundant.The surface layers of paddy fields with different parent materials There was significant difference in soil microbial biomass carbon content, with the highest in Ipomoea aquatica, and the lowest in river sand and reddish brown, while the organic carbon content was the highest in reddish brown and river sand, while the rest of the soil However, there was no significant difference between soil microbial biomass carbon and soil organic carbon, and there was a significant positive correlation between soil microbial biomass carbon With the increase of soil depth, the micro-organisms in tillage layer of different types of tillage were relatively lowest with river sand (2.11%) and reddish yellow mud (1.37%), while the highest in the paddy soil with developed slate (8.24%), , Indicating that the river sand mud and red yellow mud substrate is significantly lower than the effectiveness of the yellow muddy field, which is the river sand and red and yellow mud organic carbon highest and lowest microbial biomass one of the reasons. Soil microbial biomass carbon content and There was a significant positive correlation between total nitrogen, available nitrogen and available phosphorus in soil, but not obvious correlation with available potassium in soil, indicating that the microbial biomass carbon in paddy soils was more complicated than that in soil with the exception of organic carbon Relationship.