摘要
强烈的人为作用造成我国西南喀斯特区水土流失严重,并导致了石漠化。而碳酸盐岩风化后残留物极少,土壤形成速度极慢,又导致石漠化的恢复极难。因此,西南喀斯特区石漠化的核心问题就是土壤形成与流失的矛盾。目前对于碳酸盐岩成土速率的计算,都是基于剖面上碳酸盐岩溶蚀速率来推算的,溶蚀速率是通过灰岩标准试片溶蚀速率确定的,只考虑了岩-土接触面上的碳酸盐岩溶蚀速率,不考虑碳酸盐岩岩层间和岩体内部的风化作用。而可以包含以上3种成土模式的流域地球化学平衡法,则是在花岗岩地区建立起来的,应用在碳酸盐岩上,必须对其进行修正。碳酸盐岩的风化成土与花岗岩的差异较大,碳酸盐岩的风化分成2个过程,即碳酸盐岩风化形成残积物和残积物进一步风化形成土壤。在综述前人研究成果的基础上,提出了在风化速率计算中增加残积物风化模块,以区分碳酸盐岩基岩与残积物2个不同风化过程的方法,来修正基于花岗岩建立的流域地球化学平衡法,以适合碳酸盐岩上土壤形成速率的计算。
Human activities have induced severe soil and water loss and gave rise to rocky desertification in Karst region of southwest China.The recovery of rocky desertification is extremely difficult because there’s very little res-idue after the weathering of carbonate rocks.Therefore,the key issue of karst rocky desertification is the contradic-tion between soil formation and soil loss.Currently,the rate of soil formation from carbonate rock is calculated based on the dissolution rate of carbonate rock in soil profile.The dissolution rate of carbonate rock is determined by the dissolution experiment of standard test piece of carbonate rock.This method only considers the soil formation on the contact surface between soil and rock,but not the soil formation between rock layers and rock interior.How-ever,the method of watershed’s geochemical balance which contains the above soil formation types is based on the granite region.It must be modified when applied to carbonate rock watershed.The most important difference of the soil formation between carbonate and granite rocks was the weathering of carbonate rocks diametrically divided into two processes,namely the weathering of carbonate rock to form residual material,and the further weathering of re-sidual material to form soil.In this paper,we propose to modify the method of watershed’s geochemical balance by considering the weathering process of residual material to distinguish these two processes.
出处
《长江科学院院报》
CSCD
北大核心
2015年第3期64-72,共9页
Journal of Changjiang River Scientific Research Institute
基金
国家自然科学基金项目(41101191
41201269)
国家科技重大专项专题资助项目(2012ZX07503-002-03)
中央级公益性科研院所基本科研业务费资助项目(CKSF2014022/TB
CKSF2015011/TB)
长江科学院创新团队资助项目(CKSF2012052/TB)
关键词
西南地区
喀斯特石漠化
碳酸盐岩风化
土壤形成速率
花岗岩
溶蚀速率法
流域地球化学平衡法
Southwest China
Karst rocky desertification
weathering of carbonate rock
soil formation rate
gran-ite
dissolution rate
method of watershed’s geochemical balance
