地理学报 ›› 2005, Vol. 60 ›› Issue (5): 751-760.doi: 10.11821/xb200505006

• 环境演变与土地利用 • 上一篇    下一篇

典型岩溶农业区土地利用变化对土壤性质的影响——以云南小江流域为例

蒋勇军1, 袁道先1,3, 章程1,3, 况明生1, 王建力11, 谢世友2, 张贵2   

  1. 1. 西南大学资源与环境科学学院,重庆 400715;
    2. 云南省地质调查院,昆明 650041;
    3. 中国地质科学院岩溶地质研究所、国土资源部岩溶动力学开放研究实验室,桂林 541004
  • 收稿日期:2005-06-09 修回日期:2005-07-28 出版日期:2005-09-25 发布日期:2005-09-25
  • 作者简介:蒋勇军 (1968-), 男, 汉族, 湖南益阳人, 副教授, 博士, 主要从事资源环境与GIS应用等方面的研究。mail: jiangjyj@swu.edu.cn
  • 基金资助:

    西南大学自然地理学重点学科开放基金项目(250-411109); 重庆市科委项目 (20027534; 20048258); 国土资源部项目(200310400024)

Impact of Land Use Change on Soil Properties in a Typical Karst Agricultural Region: A Case Study of Xiaojiang Watershed, Yunnan

JIANG Yongjun1, YUAN Daoxian1,3, ZHANG Cheng1,3, KUANG Mingsheng1, WANG Jianli11, XIE Shiyou2, ZHANG Gui2   

  1. 1. College of Resources and Environment Science, Southwest University, Chongqing 400715, China;
    2. Institute of Geology Investigation in Yunnan Province, Kunming 650041, China;
    3. Institute of Karst Geology, CAGS, Karst Dynamics Laboratory, MLR, Guilin 541004, China
  • Received:2005-06-09 Revised:2005-07-28 Online:2005-09-25 Published:2005-09-25
  • Supported by:

    The Open Foundation of Physical Geography of Southwest China University, No.250-411109; Foundation of Science and Technology Committee of Chongqing, No.20027534; No.20048258); Project of Ministry of Land and Resources, No.200310400024

摘要:

以云南省泸西县小江典型岩溶农业流域为研究单元,分析了流域1982~2003年土地利用的变化及定点对比分析不同土地利用变化下土壤性质的变化,结果表明:小江流域1982~2003年610.12 km2的土地利用发生了变化,变化类型主要是由未利用地向耕地、林地以及林地向耕地的转变,人口的增加、社会、经济的发展和理智的生态决策是流域土地利用变化的主要原因;林地、未利用地转变为耕地后,土壤有机质、全氮、全磷含量大幅度降低,土壤pH明显升高,全钾、速效钾含量增加;短时间的退耕还林,土壤性质变化不明显;耕地转变为园地后,土壤性质得到明显的改善;而耕地转变为石漠化土地后,土壤性质发生显著变化,土壤有机质、全氮、全磷、碱解氮、速效磷含量大幅度降低,土壤pH明显升高;同时,研究表明土地利用变化对碳酸盐岩地层中发育的土壤性质的影响强度明显大于砂页岩地层中发育的土壤,表明碳酸盐岩地层中发育的土壤十分脆弱。

关键词: 岩溶农业区, 土地利用, 土壤性质, 小江流域, 云南

Abstract:

Karst has been regarded as a fragile environment by environmental scientists. Because of karst system with a low capacity, it is difficult to restore if once disturbed. Changes in environment are not unique throughout the karst region, but a karst region is more sensitive than other regions. In the present study we analyzed the land use changes from 1982 to 2003, and assessed the effects of land use changes on pH value, organic matter (OM), total nitrogen (TN), total phosphorus (TP), total potassium (TK), available nitrogen (AN), available phosphorus (AP), available potassium (AK) in soils of Xiaojing watershed, a typical karst agricultural region in Yunan province, Southwest China. The results indicate: (1) The total land converted covers an area of 610.12 km2, of which 134.29 km2 of forestland were converted into cultivated land, and 210 km2 of unused land were converted into cultivated land during the past 20 years in Xiaojiang watershed. (2) The rapid growth of population and the economic development were the main driving forces of cultivated land change, and the comparative economic benefits from the macro-policies such as eco-environmental protection were important driving forces of forestland change in Xiaojiang watershed during the past 20 years. (3) Because of land use change, the soil properties have been changed significantly. The pH value, OM, TN, TP, TK, AN, AP and AK in soils in 1982 were 6.3, 38.02 g/kg, 1.86 g/kg, 1.63 g/kg, 10.94 g/kg, 114.42 mg/kg, 11.65 mg/kg and 64.69 mg/kg, respectively; and those in 2003 were 6.73, 25.26 g/kg, 1.41g/kg, 0.99 g/kg, 12.6 g/kg, 113.43 mg/kg and 11.11 mg/kg, 151.59 mg/kg, respectively. Pared samples t-test of the tested indices of soil properties indicate that those indices have changed significantly during the past 20 years. (4) Because of the differences of land use change, the soil properties change differently. The contents of the soil OM, TN, TP in 2003 were significantly lower than those in 1982 after the forestland and unused land were converted into cultivated land, but the pH of soil increased significantly in 2003, especially the properties of the soils developed from the carbonate rock strata changed most significantly. The soil properties change was mainly attributed to deforestation, water and soil erosion, and the low land management level after the forestland and unused land were converted into the cultivated land. Because of lack of the vegetation cover and the land management, the contents of soil OM, TN, and TP for short-time reforested land also decreased, but the soil pH increased. Because of the use of more fertilizer and the improvement of land management, the soil properties improved significantly after the cultivated land was converted into orchard land. But due to unreasonable human activities to the fragile soils in the karst region, the land became rock desertified. The content of the soil OM, TN, TP, AN and AP decreased significantly, but the soil pH increased significantly after land converted became rock desertified. (5) Also, with the changes in land use and soil ameliorative measures, the modifications of properties of soils developed from the carbonate rock strata were more sensitive than those from the sandstone strata.

Key words: land use, typical karst agricultural region, soil properties, Xiaojiang watershed, Yunnan