青海省南部高寒区土地退化格局与程度评价

土地退化是青藏高原严重的渐发性自然灾害之一.青海省南部高寒区地处青藏高原腹地,是江河源头区、气候变化敏感区、生态环境脆弱区和少数民族聚居区,是中国可持续发展的生态屏障.在分析该区土地退化态势的基础上,利用区位指数法探讨了土地退化的基本格局.目前该区形成了以沙化型退化、黑土滩型退化和鼠害型退化为主导,其他类型(冻融侵蚀型退化、毒杂草型退化、虫害型退化、盐碱型退化及水力侵蚀、风力侵蚀等)发育不等的土壤退化体系,具有退化类型的多样性、分布的广泛性、程度的严重性、发展的快速性、危害的长期性、影响的深远性.利用综合评价指数法对土地退化程度进行了评价,并根据评价结果划分了极重度退化区(玛多、达日县)、重度退化区(曲麻莱、称多、玉树、同德、泽库、班玛县)、中度退化区(治多、杂多、囊谦、兴海、玛沁、甘德、久治、河南县)和轻度退化区(格尔木市唐古拉山乡)4个土地退化等级区域.

Situation Analysis of Land Degradation in High Cold Region of Southern Qinghai Province

Land degradation was one of the serious gradual occurring natural disasters on Qinghai-Tibet Plateau.The southern part of Qinghai province locating in the hinterland of Qinghai-Tibet Plateau was the river source region sensitive to climate change sensitive with fragile ecological environment area which was inhabited by ethnic minorities,and was ecological barrier for sustainable development of China.The land degradation trend in this region was discussed using location index method based on analysis of land degradation pattern.At present,the main deteriorated patterns of this area were desertified deteriorated,black beach degradation and rodent degradation together with some other types(freeze-thaw erosion degradation,poisonous weeds degradation,pest deteriorated,salinity-type degradation and water erosion,wind erosion,etc.).The degradation system was with characters of various degraded type,wide distribution,serious degree,rapid development,sever hazard and far-reaching impact.The comprehensive index evaluation method was adopted to evaluate the degree of land degradation.According to the evaluation results,the land was divided into 4 degradation grades including extremely severe degradation zone(Maduo,Dari county),severe degradation zone(Qumacai,Chenduo,Yushu,Tongde,Zeku,Banma county),moderate degraded zone(Zhiduo,Zaduo,Nangqian,Xinghai,Maqin,Gande,Jiouzhi,Henan county) and mild degraded zone(Tanggulashan township).