摘要
应用分形理论的相关模型对黄土高原子午岭地区林地及不同开垦年限的农地土壤团粒结构分形特征进行了研究。结果表明 :林地和不同开垦年限的农地土壤团粒结构分形维在 2 .32～ 2 .91之间 ,表现为 >0 .2 5mm的团聚体含量越低 ,其结构的分形维越高。分形维与水稳性团聚体含量之间呈显著线性关系。林地和不同开垦年限农地表层土壤的物理性质随土壤团聚体的分形维变化而变化 ,即分形维越小 ,>0 .2 5mm的团粒含量越高 ,土壤容重也越小 ,土壤疏松 ,土壤通气度大 ,土壤涵蓄水分与供应作物生长所需水分的能力越好 ;分形维越大 ,>0 .2 5mm的团粒含量低 ,土壤容重也越大 ,土壤紧实 ,土壤通气度小 ,则土壤涵蓄水分与供应作物所需水分的能力越差。上述结果在一定程度上表明 ,植被遭到破坏、不合理的人为开垦 ,是土壤退化和生态环境恶化的主要原因 ;恢复和重建植被 ,增加地面覆盖 ,应为加速黄土高原综合治理的基本内容。
The fractal theory, a new study tool, has been widely applied in soil sciences in recent years. The fractal features of soil granule as well as progress made in soil science research on grain distribution, soil moisture, soil bulk capacity variance and so on are discussed. Based on the fractal theory and relative model, the fractal features of soil granule structure of forest land and different reclaimed farmland were studied in this paper. The results show that the fractal dimension of soil granule structure of forest land and different reclaimed farmland are between 2.32～2.91. The less the contents of the granule >0.25 mm and the water-stable granule, the more the fractal dimension of soil granule and the higher the soil fertility are. There exists close relationship between fractal dimension of soil granule and the contents of soil granule or water-stable granule composition in all kinds of land. The soil physical properties of forest land and different reclaimed farmland vary with the variations of the fractal dimension. The less the fractal dimension, the more the contents of >0.25 mm soil granule and the less the soil bulk density, the better the soil self-restraint capacity. The more the fractal dimension, the less the contents of >0.25 mm soil granule and the greater the soil bulk capacity, the less the soil self-restraint capacity. The results show to certain extent that man-made unreasonable land use is the main cause of soil degradation and eco-environmental deterioration.Vegetation recovery and vehabilitation as well as increase ground coverage are principal countermeasures to reduce the Yellow River sedimentation and accelerate comprehensive control of the Loess Plateau.
出处
《地理研究》
CSCD
北大核心
2002年第6期700-706,共7页
Geographical Research
基金
国家自然科学基金资助项目 (40 0 2 5 10 2 )
