不同土地利用方式土壤有机碳变化特征及与重金属的相关性分析

研究旨在探讨土地利用方式对土壤碳库储量的影响，以及不同土地利用方式土壤典型重金属与SOC储量之间的关系。采用现场分层采样（表、中、深层）及室内计算分析，调查了甘肃中西部12 个市县区，不同土地利用方式下土壤有机碳(SOC)储量变化特征，同时通过引入有机碳丰度值和相关系数，初步阐明了土壤重金属与SOC变化之间的相关性。结果得出：调查区内土壤有机碳丰度值呈现出的大小顺序为林地、建设用地、园地、耕地和草地；此外，典型土壤重金属Hg、Cd、Cr、As、Pb 与SOC储量之间存在显著相关性，园地和建设用地最高r=0.99，林地和耕地次之，分别为r=0.87 和r=0.86。可见，土壤在不同开发利用方式下，有机碳储量及有机碳丰度值呈现出较大差异性，同时也定量证明了SOC与土壤典型重金属储量密切相关。

Soil Organic Carbon Under Different Land Use Patterns: Change Characteristics and Its Correlation with Soil Heavy Metals

The study is to explore the correlation between land use patterns and soil carbon pool, soil heavy metals and SOC under different land use patterns. Through stratified sampling (topsoil, middle-level soil and deep soil) and in-door computational analysis, the variation characteristics of SOC reserves under different land use types in 12 cities and counties of central and western Gansu were investigated. The index of soil organic abundance and correlation coefficient were introduced to clarify the correlation between soil heavy metals and SOC. The results showed that, the order of soil organic abundance value was forest＞land for construction＞ garden plot＞cultivated land＞ lawn; besides, the correlation of SOC and 5 typical heavy metals (Hg, Cd, Cr, As and Pb) was significant, garden and the land for construction had the highest r of 0.99, the forest and the cultivated land took the second place, with r=0.87 and r=0.86 respectively. In conclusion, land use patters influence SOC reserves, and the quantitative analysis indicate that the soil heavy metal reserves are closely related to organic carbon contents.