| 亚热带不同稻田土壤微生物生物量碳的剖面分布特征 |
| 摘要点击 4354 全文点击 2127 投稿时间：2012-07-13 修订日期：2012-08-17 |
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| 中文关键词 水稻土 母质 有机碳 微生物生物量碳 底物有效性 |
| 英文关键词 paddy soil parent material organic carbon microbial biomass carbon substrate availability |
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| 中文摘要 |
| 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4.55~1691.75 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. |
| 英文摘要 |
| The soil microbial biomass carbon (Cmic), one of the most active components of soil organic carbon (Corg), is an effective indicator of soil quality. In the present study, five subtropical paddy soils developed from different parent materials were selected, and the distribution of Cmic through the profiles was studied, as well as the relationship of Cmicwith Corg and soil nutrients. The results showed that the contents of Corg and Cmic decreased markedly with increasing soil depth, ranging from 2.45 g·kg-1 to 26.19 g·kg-1 and from 4.55 mg·kg-1 to 1691.75 mg·kg-1, respectively. They mainly concentrated in the surface layer (plough horizon and plough pan). The content of Cmic varied significantly in paddy soils developed from different parent materials, with the highest one in yellow clayey soil, and the lowest ones in alluvial sandy soil and reddish yellow clayey soil. This was on the contrary to the distribution of Corg in the surface paddy soils, since the reddish yellow clayey soil and alluvial sandy soil showed higher contents while other types of paddy soils exhibited similar contents of Corg. Notwithstanding, Cmicwas still controlled by the quantity of Corg and positively correlated with Corg. The ratio of Cmic to Corg (Cmic/Corg) decreased with increasing soil depth and differed in the plough horizon between different paddy soils, with lower values in alluvial sandy soil (2.11%) and reddish yellow clayey soil (1.37%) but higher value in reddish yellow clayey soil Ⅰ (8.24%). It indicated that the microbial substrate availability in alluvial sandy soil and reddish yellow clayey soil was lower than those in reddish yellow clayey soils. The content of Cmic was significantly positively correlated with total nitrogen, alkali-hydrolyzable N and Olsen-P, but was irrelevant to available K. It is implied that the Cmic was not only controlled by Corg, but also complicatedly interacted with soil nutrients in paddy soils. |
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