我国北方草原沙漠化过程中土壤碳、氮变化规律研究

对内蒙古锡林郭勒盟多伦县境内75个样点土壤质地、全碳、全氮的测定和地上植被状况分析结果表明，草原沙漠化过程不同阶段的变化体现在土壤氮、碳、粘粒含量的有规律变化，土壤氮、碳含量减少、质地变粗；土壤氮、碳含量与粘粒含量间呈显著相关性，氮含量与粘粒含量间的相关系数(0．901)分别大于碳、氮含量间的相关系数(0．627)和碳含量与粘粒含量间的相关系数(0．642)．土壤中粘粒含量显著减少．土壤中氮元素的衰减比碳元素明显；沙质草原沙漠化不同阶段的C／N比呈现增加的趋势．

Soil C and N dynamics during desertification of grassland in Northern China

This paper investigated the aboveground vegetations and the soil texture and total C and N at 75 sites of Duolun County in Xilinguole League of Inner Mongolia. The results showed that different types of vegetation community could be used to describe different stages of desertification process. During desertification, the community types were changed in the series of Leymus chinensis + Cleistogenes squarrosa --> Artemisia frigida --> Artemisia intramongolia --> Corispermum staunyonii, Chenopodium bryoniaefolium --> drift sand, and a regular change of soil clay and total C and N contents could also be found. The soil C/N ratio was increased with different stages of grassland desertification, which could be expressed in the series of 8.11-->13.96-->12.36-->28.17.