摘要
青藏高原是我国重要生态屏障。近年来,青藏高原大面积的退耕或开垦等土地利用变化,势必会减弱或诱发土壤侵蚀。为揭示青藏高原不同土地利用变化模式对土壤侵蚀的影响,以青藏高原农耕区为例,基于CSLE模型,解析了农耕区2015年土壤侵蚀状态,首次提出了土壤侵蚀强度变化综合指数与减蚀贡献度的概念及计算公式,量化了耕地变化对土壤侵蚀造成的影响,分析了不同耕地变化模式对土壤减蚀的贡献。结果表明:(1)2015年青藏高原农耕区的平均土壤侵蚀模数为195.61t/(hm^(2)·a),潜在土壤流失量达446.51亿t/a;(2)退耕还林、退耕还草和未利用地转耕地的土壤侵蚀强度变化综合指数分别为-378.24、-118.54和-5.44 t/(hm^(2)·a),减蚀作用依次降低;草地、林地开垦为耕地和耕地退化为未利用地的土壤侵蚀强度变化综合指数分别为16.53、32.34和200.61t/(hm^(2)·a),增蚀作用依次增大;(3)2000-2015年间的土地利用变化使得青藏高原农耕区的土壤侵蚀强度减少245.54 t/(hm^(2)·a),较土地利用不变情景下降55.66%。在土壤侵蚀强度变化综合指数和面积的双重影响下,不同土地利用变化对农耕区土壤减蚀量的贡献排序为:退耕还草>退耕还林>未利用地转耕地>林地转耕地>耕地转未利用地>草地转耕地,为青藏高原农耕区水土资源可持续开发利用和生态环境保护提供了参考。
The Qinghai-Tibet Plateau(QTP)is an important ecological barrier in China. In recent years,the large-scale conversion and reclamation of farmland in the QTP are bound to weaken or induce soil erosion. To explore the impact of different land-use change patterns on soil erosion in the QTP,taking the farming area of the QTP as an example,based on the CSLE model,the soil erosion status of the farming area in 2015 is analyzed,and the comprehensive index of soil erosion intensity change and the contribution of erosion reduction is proposed for the first time. The concept and calculation formula is used to quantify the impact of cultivated land changes on soil erosion and analyze the contribution of different cultivated land change patterns to soil erosion reduction. The results show that:(1) The average soil erosion module in the farming areas of the QTP in 2015 is 195.6 t/(hm^(2)·a),and the potential annual soil loss is approximately 446.51 × 10^(6) t/a.(2) The composite index of variation in soil erosion intensity in returning farmland to forest,back tillage to grass,and unused land-to-farmland are-378.24,-118.54 and-5.44 t/(hm^(2)·a),and the effect of reducing soil erosion decreases in turn,while the composite index of variation in soil erosion intensity in grassland and forest land reclamation as cultivated land,and farmland that degrades into unused land are 16.53,32.34 and 200.61 t/(hm^(2)·a),the effect of increasing soil erosion increased in turn.(3) Land-use changes in 2000-2015 reduced soil erosion intensity by 245.54 t/(hm^(2)·a)in the agricultural areas of the QTP with a decrease of 55.66% compared to the unchanging land-use scenario.Under the dual influence of soil erosion intensity change comprehensive index and area,the order of contribution of different land-use changes to soil erosion reduction is:returning farmland to grassland > returning farmland to forest > conversion of unused land to cultivated land >conversion of woodland to cultivated land > conversion of cultivated land to unused land > conversion of grassland to cultivated land. The research results provide a reference for the sustainable development and utilization of water and soil resources and ecological environmental protection in the agricultural areas of the QTP.
作者
周柽
邵东国
顾文权
姚明磊
ZHOU Cheng;SHAO Dong-guo;GU Wen-quan;YAO Ming-lei(State Key Laboratory of Water Resources and Hydropower Engineering Science,Wuhan University,Wuhan 430072,China)
出处
《中国农村水利水电》
北大核心
2022年第3期120-126,133,共8页
China Rural Water and Hydropower
基金
中国科学院战略性先导科技专项(A类)课题(XDA20040300)
国家重点研发计划项目(2019YFC0408905)
国家自然科学基金项目(51709204)。
