【作者】 王冬银；

【导师】 谢世友； 章程；

【作者基本信息】 西南大学 ， 自然地理学， 2008， 硕士

【摘要】 前人在研究中肯定了岩溶区内CO₂浓度的时空变化对溶蚀速率的驱动作用,然而不同的土地利用方式产生的土壤理化性质差异和变化对岩溶作用的方向和强度也具有较大的影响。在2006.4-2007.4时间内通过野外溶蚀标准试片法,测试得出重庆金佛山岩溶区山脚碧潭泉和山顶水房泉附近的5种典型土地利用方式下的6个测试点的雨季和旱季的溶蚀量。测试结果表明同一海拔不同土地利用方式下的测试点,不同海拔相同利用方式下的测试点及6个测试点之间的溶蚀速率都存在较大的时空差异,具体结论如下:（1）气候因子尤其是雨量对溶蚀速率有明显控制作用,溶蚀速率主要取决于水剩余量（即降水和蒸发之差）,气温通过影响降雨可以促进或抑制岩溶过程。测试时间内金佛山碧潭泉和水房泉附近的6个测试点的溶蚀速率高于其它同纬度测试区的标准溶蚀试片的观测速率,且雨季的溶蚀速率快于旱季;从小区域上来看,水房泉测试点的雨季和旱季试片溶蚀速度快于碧潭泉测试点。（2）岩溶区不同土地利用方式下的溶蚀量大小存在显著差异,标准溶蚀试片溶蚀量和土壤有机质含量、CO₂浓度以及土壤含水量和土壤孔隙度成正相关关系,与土壤pH值成负相关关系。水房泉林地、竹林地和草地3个测试点位于生态保护良好的金佛山山顶原始生态区,其岩溶作用主要受土壤CO₂、土壤有机质含量和土壤pH值的综合影响;而碧潭泉林地、灌草丛和耕地位于金佛山自然保护区和非保护区的交界地带,地表植被状况和土壤理化性质尤其是灌草丛和耕地2个测试点受人类活动影响较大,其土下岩溶作用随土壤剖面而不断的下降。（3）不同的土地利用方式影响了土壤理化性质的尤其是土壤有机质含量,导致金佛山6个测试点的土下岩溶作用的巨大差异性。雨季土壤剖面平均溶蚀量依次排列为:水房泉竹林地（133.41mg）＞水房泉林地（88.14mg）＞水房泉草地（75.29mg）＞碧潭泉林地（20.44mg）＞碧潭泉灌草丛（13.68mg）＞碧潭泉耕地（5.16mg）;6个测试点旱季土壤剖面平均溶蚀量依次排列为:水房泉林地（58.40mg）＞水房泉草地（49.63mg）＞水房泉竹林地（43.48mg）＞碧潭泉林地（14.75mg）＞碧潭泉灌草丛（7.15mg）＞碧潭泉耕地（6.65mg）。（4）6个测试点土壤剖面（土下0～50cm）的3个溶蚀作用测试层位（-0cm,-20cm,-50cm）由于受不同深度土壤有机质含量、土壤CO₂浓度、土壤水份和土壤pH土壤剖面差异性的影响,每个测试点土壤剖面测试层位的岩溶作用大小也有较大的差异性。（5）岩溶区溶蚀作用的产生是一个综合复杂的过程,空气和土壤中的CO₂、土壤有机质、土壤CaCO₃含量、土壤湿度、地表植被、地区气候（气温,降水）、人类活动等都能影响到溶蚀速度,其中土壤中的生物活动及其产物可能为岩溶作用中最活跃的因素,地表植被覆盖程度高低以及植被的演化有可能对改善岩溶动力系统的三相条件起着积极或消极的作用,从而促进或延缓了岩溶作用的进行。同时,通过对测试点的土壤剖面基本理化性质分析和地球化学元素分析发现不同土地利用方式下测试点的土壤基本肥力特征存在较大差异性,主要结论如下:（1）金佛山岩溶山区6个测试点的土壤有机质含量除受富钙环境影响外,受地表植被状况和利用方式的影响,土壤有机质含量都较高且随土壤深度而下降,但还表现出完全自然保护区、保护区与非保护区交界地带的差异,6个测试点土壤剖面有机质平均含量由高到低依次排列为:水房泉林地＞水房泉竹林地＞水房泉草地＞碧潭泉林地＞碧潭泉灌草丛＞碧潭泉耕地。（2）金佛山岩溶山区6个测试点的土壤氮素含量较高,土壤剖面全氮含量属于国家一级水平;土壤中全氮和水解性氮含量具有很强的一致性,即全氮含量高的土壤测试点和土壤测试层面,土壤水解性氮含量也较高;土壤剖面全氮和水解性氮平均含量由高到低排序相同,为:水房泉林地＞水房泉竹林地＞水房泉草地＞碧潭泉林地＞碧潭泉灌草丛＞碧潭泉耕地。（3）金佛山岩溶山区6个测试点的土壤磷素含量较高,土壤剖面全氮含量属于国家一级水平;土壤中全磷和速效磷含量具相关性并不明显,土壤剖面全磷平均含量由高到低排序为:水房泉林地＞水房泉草地＞水房泉竹林地＞碧潭泉灌草丛＞碧潭泉耕地＞碧潭泉林地,速效磷排序为:水房泉林地＞水房泉竹林地＞碧潭泉耕地＞水房泉草地＞碧潭泉林地＞碧潭泉灌草丛。（4）金佛山岩溶山区6个测试点的土壤钾素含量较低,平均仅5.07g·kg^-1,属于国家五级水平;6个测试点的土壤剖面全钾平均含量由高到低排序为:水房泉竹林地＞水房泉草地＞碧潭泉耕地＞碧潭泉灌草丛＞碧潭泉林地＞水房泉林地,速效钾排序为:水房泉竹林地＞碧潭泉林地＞水房泉草地＞碧潭泉灌草丛＞水房泉林地＞碧潭泉耕地。本研究中的金佛山岩溶山区6个测试点主体都位于国家自然保护区内,地表植被丰富,覆盖率较高,从岩溶系统动力学的观点来看,金佛山岩溶植被生长发育有助于岩溶生态系统状态的改善和稳定,而岩溶生态系统的稳定反过来也有利于区域内植被-土壤系统的生长发育。综合总结可以得出土地覆盖变化与岩溶作用相对应的减弱过程:林地→灌木丛→灌草丛→灌丛→耕地→石漠地。更多还原

【Abstract】 Previous studies on karst processes was always focused on karstification intensity and its variation under different geological settings,climatic and hydrologic conditions in the view of macroscale,and considering changes of CO₂ density driving krast processes in a certain area,or the contribution of carbonate rock weathering to the atmospheric CO₂ sink.It has been recognized that intensity of karst processes could be largely affected by soil’s physical and chemistry properties. Less attention was paid to the impact of land-use types on karst processes in mountain area.These properties are closely related to types of land cover.Filed dissolution test of standard limestone tablets,carried out in the karst regions of Bitan spring which located on 800m elevation and Shuifang spring which located on 2100m elevation in Jinfo mountain of Chongqing,in rainy season and dry season of 2006-2007,where five types of land-use and six test sites were encountered. Almost all the typical land-use types occurred in the small study area,so the present study is also typical and representative.There is the special weather which its beginning with mid-July 2006 that little rain and high temperature had being for more than 40 days in Chongqing.The results showed that the corrosion ratio was some difference between the rainy season and dry season,and at different elevations is quite different that corrosional ratio in Shuifang spring is more quicker than that of in Bitan spring during the test time,revealed that limestone dissolution was related to corrosion speed of the soil,and the soil’s corrosion speed was different with land-use types in study area.Moreover,it was also found that the soil’s corrosional ratio was different at different elevation for the same land-use type.At the six test sites,different land-use patterns affect the soil physical and chemical properties of soil organic matter content in particular,resulting in the karst process,six tests corrosion speed under the soil have great differences.Soil profile dissolution of the rainy season ranked as follows:bamboo forest land of Shuifang spring（133.41mg）>forest of Shuifang spring（88.14mg）>meadow of Shuifang spring（75.29mg）>forest of Bitan spring （20.44mg）>shrub of Bitan spring（13.68mg）>tilled land of Bitan spring（5.16mg）;Six tests soil profile dissolution of the dry season ranked as follows:forest of Shuifang spring（58.40mg）> meadow of Shuifang spring（49.63mg）>bamboo forest land of Shuifang spring（43.48mg）>forest of Bitan spring（14.75mg）>shrub of Bitan spring（7.15mg）>tilled land of Bitan spring（6.65mg）.This study further found that except basic factors controlling karstification,such as rainfall,the temperature and CaCO₃ content in soils,CO₂ density and organic content within soil were other two particular factors in the study area.Dissolution process is controlled remarkably by soil organism in forest,shrub and tilled land of Bitan spring,the higher the organism content is and the less the pH value is,the higher the dissolution rate is.And the dissolution rate affected mainly by soil CO₂ in bamboo forest and meadow of Shuifang spring,it has imperceptible relativity with organism content. But forest of Shuifang spring’s dissolution rate affected by both of soil CO₂ and soil organism.Six soil tests under different land-use patterns of Shuifang spring and Bitan spring in Jinfo mountain have a larger differences in soil fertility,the difference type-use patterns of the same soil profile fertility status have some differences,and the soil fertility of the same type-use pattern at different altitude also have a big difference.Six soil tests under different land-use patterns of Shuifang spring and Bitan spring in Jinfo mountain under the soil organic matter content by the addition of calcium rich environmental impact, the state of vegetation and use of soil test have a high content of organic matter and decreased with soil depth,but also displayed the full nature reserves,protected areas and non-protected areas of the border differences,six test points average content of organic matter in soil profile arranged in descending order:forest of Shuifang spring> bamboo forest land of Shuifang spring>meadow of Shuifang spring>forest of Bitan spring>shrub of Bitan spring >tilled land of Bitan spring.Six soil tests under different land-use patterns of Shuifang spring and Bitan spring in Jinfo mountain under the soil nitrogen contents are all high level nitrogen content,and the total nitrogen content and available nitrogen in soil have the same descending order that are:forest of Shuifang spring>bamboo forest land of Shuifang spring>meadow of Shuifang spring>forest of Bitan spring>shrub of Bitan spring >tilled land of Bitan spring.Six soil tests under different land-use patterns of Shuifang spring and Bitan spring in Jinfo mountain have a high content of phosphorus in the soil.The available phosphorus and total phosphorus content in six measurement soil points is not associated with each other obviously,the average total phosphorus content of the soil profiles in descending order is:forest of Shuifang spring>meadow of Shuifang spring>bamboo forest land of Shuifang spring>tilled land of Bitan spring>shrub of Bitan spring>forest of Bitan spring.And the available phosphorus of soil in descending order is:forest of Shuifang spring>bamboo forest land of Shuifang spring >tilled land of Bitan spring>meadow of Shuifang spring>forest of Bitan spring >shrub of Bitan spring.Six soil tests under different land-use patterns of Shuifang spring and Bitan spring in Jinfo mountain under the soil potassium have a less level of a state 5 in national levels,all of the average soil profile tests’ total potassium in the soil is 5.07 g·kg^-1;the soil total potassium content of six tests points in descending order is:bamboo forest land of Shuifang spring>meadow of Shuifang spring>tilled land of Bitan spring>shrub of Bitan spring>forest of Bitan spring>forest of Shuifang spring.And the available potassium content of six tests points in descending order is:bamboo forest land of Shuifang spring>forest of Bitan spring>meadow of Shuifang spring>shrub of Bitan spring>forest of Shuifang spring>tilled land of Bitan spring.The study area of six test points in Shuifang spring and Bitan spring are located in the main national nature reserve area in Jinfo mountain,from the karst system dynamics perspective,there are a rich vegetation and a higher coverage,therefore,the karst vegetation in Jinfo mountain contribute to the growth and development of karst ecosystem stability and the improvement of the state,and karst ecosystem stability is conducive to regional growth of the vegetation - soil system too.更多还原