三峡库区紫色土植被恢复过程的土壤团粒组成及分形特征  

Composition and fractal features of purple soil aggregates during the vegetation restoration processes in the Three Gorges Reservoir Region

作　　者：王轶浩[1] 耿养会[1] 黄仲华[1] 

机构地区：[1]重庆市林业科学研究院重庆市三峡库区森林生态保护与恢复市级重点实验室,重庆400036

出　　处：《生态学报》2013年第18期5493-5499,共7页Acta Ecologica Sinica

基　　金：国家林业公益性行业科研专项(201004039);重庆市科委基本科研业务费专项(BS1002)联合资助

摘　　要：采用空间代替时间方法,研究了三峡库区紫色土植被恢复过程的土壤团粒结构特征。结果表明:与撂荒地相比,柏木新造林、幼龄林和中龄林表层土壤的5—2 mm干筛团聚体分别增加6.03%、10.32%和10.97%,而<0.25 mm干筛团聚体明显减少;各层土壤的≥0.25 mm水稳性团聚体均随植被恢复进程而明显增加,但其分形维数明显减小;紫色土水稳性团聚体的平均质量直径和几何平均直径均与≥5 mm团聚体呈极显著(P<0.01)正相关,与<0.25 mm团聚体呈极显著负相关,相反地,分形维数与<0.25 mm团聚体呈极显著正相关。研究表明三峡库区植被恢复能有效改善紫色土土壤团粒结构,且随植被恢复年限增加而增强,但是,对郁闭度过大的柏木中龄人工林,应适当抚育间伐。The quantity and quality of soil aggregates are important parameters of soil physical properties and plays an important role for sustaining soil porosity, improving soil infiltration, preventing soil erosion and so on. The Three Gorges Reservoir Region is regarded as an important region to secure the ecological safety of the mid-upper reaches of Yangtze River of China. Thus, big attention has been always paid to prevent the soil and water losses in this region, and many projects of vegetation restoration were carried out. Purple soil is the important soil resource easy to be eroded in this region. This study tries to understand and assess the changes of purple soil structure in different phases of vegetation restoration. Cupressus funebris is one of the most important tree species used for forestation and widely distributes in the low mountain and hill areas of this region. Using the method of taking space instead of time, the structure characteristics of purple soil aggregate during the vegetation restoration processes were investigated. Results showed that the dry-sieved soil aggregates in all soil layers at different restoration phases were mainly composed of particles with size ≥ 2 mm. Their ratio to the total was above 80%, but the proportion of particles with size of 0.5--0.25 mm was the least. Compared with abandoned land, the quantity of dry-sieved soil aggregates （5--2 mm） in surface soil layer for new forest land, sapling forest and mid-mature forest of Cupressusfunebris was increased by 6.03%, 10.32% and 10.97% respectively, but the dry-sieved soil aggregates of 〈0.25 mm was decreased obviously. The water stable soil aggregates at different restoration phases were mainly composed of particles with sizes 〈0.25 mm and 3-1 mm. The quantity of water stable soil aggregates of ≥0.25 mm obviously increased with the vegetation restoration processes in all soil layers, but decreased with increasing soil depth. Their fractal dimension（D） decreased significantly with the vegetation restoration pro

关 键 词：土壤团聚体 分形维数 植被恢复 紫色土 柏木 

分 类 号：S152.4[农业科学—土壤学]