土地利用方式对紫色丘陵区土壤有机碳储藏特征的影响

采取野外调查与室内分析相结合方法,对紫色丘陵区林地、撂荒地、水田、旱地土壤剖面有机碳储藏特征进行了研究.结果表明,有机碳含量均随土层深度的增加而逐渐减小,但林地、旱地、撂荒地的降低速度明显高于水田,说明黏土颗粒对控制土壤有机碳含量起着重要的作用.水田、林地相比撂荒地、旱地更利于有机碳的积累,林地有机碳含量和密度在0～5 cm土层表现出绝对的优势.随着土层深度的增加,与水田、撂荒地和旱地的差异逐渐减小,且水田有机碳含量和密度在大于10 cm土层达最大值,而撂荒地有机碳含量和密度在0 ～20 cm土层高于旱地,说明深层土壤有机碳含量和密度的增加需要一个过程,只有当表层土壤的碳含量或密度达到饱和后才能逐渐对土壤深层的碳含量有所提高.

Effect of Land Use Change on Soil Organic Carbon Storage Properties in Purple Hilly Areas

Soil storage properties under woodland,wasteland,cropland and dryland on purple hilly areas were studied with field survey and laboratory analysis.Results showed soil organic carbon decreased with increasing soil depth,and the deceasing extent in woodland,wasteland and dryland were higher than which in cropland,which showed clay particle were important to control soil organic carbon content.Compared with wasteland and dryland,soil organic carbon was more accumulated favourably in cropland and woodland.Soil organic carbon content and density in woodland displayed the maximum only top 5 cm soil depth,but the difference of which in woodland between cropland,wasteland and dryland decreased gradually with increasing soil depth,and which in cropland had an maximum when the soil depth was higher than 10 cm.Compared with dry land,wasteland was favourable to accumulate soil organic carbon in the top 20 cm soil depth.According to these analysis,we could know that increasing of soil organic carbon in subsoils need a process,and when soil organic carbon content or density in top soils reach to saturation,the subsoils carbon could increase.