珠江上游南北盘江喀斯特地区土地石漠化的成因及生态恢复模式

Formation Cause of Land Lithification in Karst Regions of Nanpan and Beipan Rivers and Mode of Ecologic Restoration

分析了珠江上游南北盘江喀斯特地区土地石漠化的形成机理:一是广布的碳酸盐岩成土物质含量低,母岩与土壤之间粘着力差,成土速度慢;二是地表与地下双层水文地质结构,水土分离,干旱缺水严重;三是植物生境严酷,生长缓慢,覆盖率低;四是超载的人口压力引发的滥采滥伐、陡坡开荒,导致严重的水土流失,是该地区土地石漠化最关键的因素。同时探究了珠江上游南北盘江喀斯特地区主要的生态恢复模式:一是以小流域为单元,山、水、田、林、路综合治理的模式提高生态容量;二是以农村能源建设为主线促进生态修复的模式提高生态休养时间;三是以培育替代产业促进农业人口转移的模式减少生态负荷;四是以有序、规范的资源开发模式减少生态干扰。

This paper analizes the mechanism of formation of land lithification in karst regions of Nanpan-Beipan rivers of the upper Pearl River： 1, low content of .soil materials in wide-spread carbonatite, poor adhesion between motber rock and soil and low soil-forming rate;2 different hydrogeologic structures for surface and underground with water separating from soil, leading to serious water shortage during drought period;3 bitter plant ecologic environment where growth rate is slow and coverage is low and 4, the most essential factors-excessive deforestation and reclamation on steep slopes, which lead to severe soil erosion. This paper also probes into following major modes of ecologic restoration in these regions： 1, comprehensively improving each small riverbasin to increase ecologic capacity ;2, promoting the mode of ecologic restoration to increase ecologic rejuvenation time; 3, accelerating the diversion of agricultural population to reduce ecologic burden and 4, carrying out ordered and norrealized development of resources to reduce ecologic interference.