黄土高原不同植被类型土壤活性有机碳组分分布特征

The Characteristics of Soil Active Organic Carbon Composition under Different Vegetation Types on the Loess Plateau

为探讨黄土高原植被恢复对土壤碳循环和有机碳库组分的影响,选取延河流域不同植被类型0~10,10~20cm土层土壤为研究对象.通过对其活性有机碳组分的研究,为土壤碳循环及植被恢复对有机碳库组分及其稳定性的影响提供理论依据。结果表明:土壤微生物量碳森林区>草原区>森林草原区,其0~10 cm土层含量比10~20cm分别高61.43%,43.00%和34.65%;轻组有机碳森林区>草原区和森林草原区;可溶性有机碳、易氧化有机碳均为森林区>草原区>森林草原区,其上层含量较下层分别增加51.21.56.63,20.65 mg·kg^(-1);2.34,-0.08,0.99 g·kg^(-1)。土壤活性有机碳表现为森林区最高,相对于森林草原区,草原区草本植被能显著提高活性有机碳含量,活性有机碳随土层深度增加其有效性降低。

The effects of vegetation restoration on soil carbon cycle and fractions of organic carbon pool in the Loess Plateau were studied with the soil samples of 0~10 cm and 10420 cm layers under different veg- etation types in Yanhe basin as research objects, and soil active organic carbon components were investiga- ted to provide theory basis for the influence of soil carbon cycle and vegetation restoration on the fractions of organic carbon pool and its stability. The results showed that the content of soil microbial biomass car- bon presented a decreasing trend that forest zone〉grassland zone〉forest-grass zone. In the 0~10 em soil layer, it was 61.43%, 43.00% and 34.65% times higher than that in the 10~20 cm soil layers. The con- tent of light fraction organic carbon in the forest zone was higher than that in the grassland and forest- grass zone. As to the content of dissolved organic carbon and easily oxidized organic carbon, a trend of for- est zone）grassland zone）forest-grass zone was found and the content of dissolved organic carbon in the upper soil layer increased by 51.21, 56.63, 20.65 mg · kg-1 compared with lower soil layer, the content of easily oxidized organic carbon increased by 2.34, --0.08, 0.99 g ·kg-1, respectively. The content of soil active organic carbon was the highest in the forest zone. In comparison with the forest-grass zone, the herbaceous vegetation in grassland zone could significantly increase the content of active organic carbon. Furthermore, the availability of active organic carbon decreased with the increase of soil depth.