多伦草原土壤理化性质在沙漠化过程中的变化  

Changes of Soil Physical and Chemical Properties in Sandy Desertification on the Duolun Prairie

作　　者：朱志梅[1] 杨持[2] 曹明明[1] 刘颖茹[2] 刘美玲[2] 

机构地区：[1]西北大学环境科学系,陕西西安710069 [2]内蒙古大学生命科学学院生态与环境科学系,内蒙古呼和浩特010021

出　　处：《水土保持通报》2007年第1期1-5,共5页Bulletin of Soil and Water Conservation

基　　金：国家重点基础研究发展规划资助项目(G2000048704);陕西省自然科学基金(2006Z05);西北大学科研基金(04NW60)和启动金(okyqdf14)

摘　　要：以典型生态脆弱区内蒙古多伦县为例,连续2 a进行了沙漠化对土壤理化性质的影响研究。结果表明,随着草原沙漠化的加剧,(1)土壤颗粒组成发生变化,黏粒含量趋于减少,砂粒增多。不同粒径对土壤团粒结构形成和保水保肥的贡献不同,黏粒的减少抑制了土壤的膨胀、可塑性及离子交换等物理性质。(2)土壤含水量下降。上层(0—20 cm)土壤含水量下降明显,随着沙漠化梯度的增加,表层土壤含水量下降速度加快,从而深层土壤含水量逐渐高于表层。(3)土壤容重呈上升趋势。容重的增加必然影响土壤中水分和空气的移动及植物根系的发育。不同深度的土壤容重与草原沙漠化也存在一定的关系,潜在阶段深土层(30—50 cm)的容重最小,而严重阶段表土层(0—5 cm)容重最小。(4)土壤有机质,C,N含量下降,方差分析显示各沙漠化梯度间均差异极显著。且土壤N的衰减要快于C。土壤C/N比呈增加趋势,说明伴随着土壤C,N的显著下降,质地变粗,植物N素供应不足更为突出。(5)土壤容重与土壤全N,C及黏粒含量的相关分析表明,细颗粒物多,有机质含量高,土壤容重即小,从而有助于提高土壤的稳定性,且5—10 cm土层的性质表现突出。(6)土壤的颗粒组成状况与土壤营养元素之间有着同增同减性,但黏粒与N的关系要密切于黏粒与C和C,N间的关系。因此土壤中细颗粒物的减少会导致N素的衰减十分明显,从而导致土壤稳定性降低。This paper studied changed properties of soils in the typical ecotone of Duolun County, Inner Mongolia for two years. Results showed that the content of clay decreased with increased sandy desertification on grassland. Soil moisture decreased significantly, especially within 20 cm of the soil surface（ P 〈 0.05）. Soil moisture in deeper layers was higher than the upper. Soil bulk density was found to increase with depth and has a certain correlation with the degree of sandy desertification in different depths. Soil bulk density in the 30-50 cm layer was the lowest in Ⅱ stage, and in the 0-5 cm layer, the lowest in Ⅴ stage. The contents of organic matter （OM）, carbon（C） and nitrogen （N） in soils decreased significantly （P 〈 0. 001 ）. The reduction in nitrogen was more rapid than carbon, which led to an increase in the C/N of soil. This indicted that the nitrogen supplying to plant was insufficient. The positive correlation between granular composition and nutrient elements was significant. The correlation between clay and N was similar to those between clay and C and between C and N. Therefore the reduction in fine particles resulted in the significant reduction in N. The correlations among soil bulk density and the contents of carbon, nitrogen and clay showed that the finer particle, the higher content of organic matter and the lower soil bulk density. This indicted an improvement in soil stability, especially in the 5-10 cm layer（P〈0. 001）.

关 键 词：生态脆弱区 草原沙漠化 多伦县 土壤特征 

分 类 号：Q948.11[生物学—植物学] S812.2[农业科学—草业科学]