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In this study, several typical loess soil as the research object, through 0 1 5cm and 15 3 0cm soil organic carbon, active organic carbon pool in each group points and the determination of soil properties, the effects of different soil types and soil depth for total organic carbon (TOC), carbon mineralization potential (Cp), microbial biomass carbon (SMBC), easily oxidized organic carbon (ROC) and the active organic carbon (LOC) effect, revealing the nature and activity of soil organic carbon pool for the further research on regional distribution characteristics of soil organic carbon, soil rich in organic carbon content, the ecological environment for the smooth construction of the Loess Plateau provides a theoretical basis . The main results and conclusions are as follows: 1. SOIL TOC between 0.20 1 6.44 g · kg -1 , at a low level. 6 soil TOC content in the order: cinnamon gt; black loam gt; loess soil gt; Xiang loess gt; Sandificational gt; alluvial soil, the difference was highly significant. (2) the cumulative mineralization of soil organic carbon concentration at 0.064 0 .596 gCO 2 -C · kg -1 range, organic carbon potential mineralization distributed in 0.06 0 .74 gC · kg -1 between. In the early stage of incubation the amount of soil organic carbon mineralization daily high, then gradually decreased. Soil types on Soil organic carbon mineralization greater impact on different soil organic carbon mineralization daily, cumulative mineralization and mineralization rates are significantly different. A kinetic equation can be well simulated loess soil organic carbon mineralization. Cp and tested soil organic carbon mineralization rate constant (k) were lower, respectively, at 0.116 0 .329 gC · kg -1 and 4.55 8 < / sup> .57 × 10-5d -1 range. Different soil Cp values ??varied greatly, while k and Cp / TOC no significant variation. 3 The soil SMBC, ROC and LOC ranged from 15.59 2 03.90 mg · kg -1 , 0.174 1 4.565 g · kg < sup> -1 and 0.031 4 .269 mg · g -1 range, coefficient of variation, uneven regional distribution. Soil type on soil microbiological properties and organic carbon oxidation stability greater impact on different soil SMBC, microbial entropy, microbial metabolic quotient (qCO 2 ), ROC, Kos and the LOC has a very significant difference sex. 4 soil depth on soil TOC, active organic carbon pool of each component and its proportion in the TOC had no significant effect, except qCO 2 and Kos, the rest of labile organic carbon content their percentage proportion of TOC with depth and showed a decreasing trend. 5 Plateau six kinds of typical cinnamon soil and loess soil active organic carbon content is higher, bioavailability strong, organic carbon oxidation stability, better soil carbon sequestration capacity; activity of aeolian sandy alluvial soil organic carbon library level is low, weak organic carbon sequestration and carbon losses. 6 Soil Cp, SMBC, ROC, LOC and soil organic carbon, total nitrogen, total phosphorus, potassium, moisture, sticky silt content and longitude significant positive correlation exists between the relationship of soil active organic carbon pool of each component With fertility, sticky particles increases. Active soil organic carbon content from south to north, from east to west in varying degrees of decline. Cp, SMBC, ROC, LOC exist between any two are highly significant correlation. qCO 2 and Kos with active organic carbon pool of each component were tested negative correlation between the two but it has a very significant positive correlation. ROC on soil TOC content changes most sensitive to changes in soil organic carbon as an indicator sensitive index.
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