干热河谷不同林地土壤有机碳和颗粒态有机碳的含量比较

[目的]研究元谋干热河谷3种林地土壤有机碳和颗粒态有机碳在0～40cm分布情况,为干热河谷土壤有机碳库的科学管理提供参考。[方法]以自然草坡（车桑子＋扭黄茅）作为对照（CK）研究银合欢人工林、余甘子＋罗望子人工林、罗望子人工林土壤有机碳含量和颗粒态有机碳含量变化。林地小区面积为20m×30m,按照蛇形取样方法每个林地随机取4个点,深度为0～40cm,每10cm一层,共4层,每层3个重复。[结果]研究表明,3种林地土壤有机碳和颗粒态有机碳含量均较低,各林地有机碳和颗粒态有机碳分布均以0～10cm为最高。有机碳和颗粒态有机碳含量最高的是罗望子林,分别达到7.7175和2.9967g/kg;最低是自然草坡,分别为3.0783和1.5950g/kg。通过对3种林地土壤有机碳含量和颗粒态有机碳含量的欧式距离比较发现,有机碳自然草坡和银合欢林相似,颗粒态有机碳自然草坡和银合欢林、罗望子林相似。[结论]干热河谷3种林地土壤有机碳和颗粒态有机碳总体含量偏低,土壤退化严重。

Comparative Study on the Content of Organic Carbon in Soil of Different Forest Lands in Dry-hot Valley

[Objective] The reference for the scientific management of organic carbon pool in the soil of dry-hot valley through the study on the distribution of total organic carbon(TOC) and particulate organic carbon(POC) in the soil of 3 types of forest lands. [Method] The content of organic carbon in natural grass land(Plantago asiatica + Anthistiria tortilis) being taken as CK,the variation of the content of TOC and POC in the artificial forest of Leucaena,emblic leaf-flower + tamarind tree and tamarind tree was analyzed. The experimental area was 20 m×30 m; the soil was sampled with the type of "Z" for four places at 4 depth points from 0 to 40 cm(10 cm/each depth point),respectively(3 repetitions/each sample). [Results] The results showed the quantity of TOC and POC in soil of 3 types of forest lands was low. The content of TOC and POC at the layer of 0-10 cm in all of forest lands was high. The highest content of TOC and POC appeared in the artificial forest of tamarind tree,with 7.717 5 and 2.996 7 g/kg; and the lowest,in natural grass land,with 3.078 3 and 1.595 0 g/kg,respectively. According to the Euclidean distance analysis of the content of TOC and POC,the content of TOC in natural grassland was similar to that in the forest of Leucaena,while POC in natural grassland was same as that in the forest of Leucaena and the forest of tamarind tree were similar. [Conclusion] The quantity of TOC and POC in the soil of the dry-hot valley was generally small and the soil was badly degraded.