若尔盖县土地沙化程度演变动态特征  

Evolution Dynamic Characteristics of Land Desertification in Zoige County,China

作　　者：何介南[1] 徐杰[1] 康文星[1] 徐伟平[1,2] 汪晓菲[1] 

机构地区：[1]中南林业科技大学生命科学与技术学院,长沙410004 [2]湖南大学经济贸易学院,长沙410008

出　　处：《林业科学》2016年第1期159-165,共7页Scientia Silvae Sinicae

基　　金：国家科技支撑计划"西南生态安全屏障决策体系"(2011BAC09B08-07)

摘　　要：[目的]探讨若尔盖县土地沙化演变趋势,为防沙治沙提供科学依据。[方法]利用若尔盖县1994,1999,2004,2009年4次土地沙漠化监测数据,采用生物统计学的转移矩阵分析方法研究沙化程度的演变动态过程。[结果]1994—2009年,若尔盖县沙地以每年11.08%的速率扩展,2009年沙地面积是1994年的4.5倍;不同沙化程度沙地的年均扩增率依次是:极重度(24.49%)>轻度(12.03%)>重度(7.80%)>中度沙化地(6.68%);沙地沙化程度以轻度为主(75.69%),土地沙化还处于初始阶段,正是沙化治理的有利时期;经过15年的沙化演变后,不同程度沙化地结构发生变化,岀现中度和重度沙化地比例下降,轻度和极重度沙化地比例上升趋势;1994—1999年,1999—2004年和2004—2009年,沙化程度保持稳定的沙地比例分别为61.53%,68.77%和83.06%,在时间系列上逐渐趋向稳定;2004—2009年沙化程度减轻的沙地比例是沙化程度恶化的2.23倍,沙化趋势朝着沙化程度减轻的方向演变;在5年的尺度上,土地沙化演变中存在渐变和跃变过程,由于跃变的存在,意味着非沙化土地不一定是最安全的,有可能在一定条件下会演变为程度严重的沙化地,同样,程度严重的沙化地在人力的治理下可以跃变为非沙化土地。在近年来加强防沙治沙情况下沙化演变趋势朝好的方向发展,但是,若尔盖县土地沙化形势依然相当严峻,治沙任务依然相当艰巨。[结论]若尔盖土地沙化程度以轻度为主,土地沙化正处在初步阶段,正是治理的有利时期。[Objective]The situation of land desertification in Zoige County of southwest China is severe. In order to provide scientific basis for prevention and control of futher desertification in this area,it is necessary to explore the evolution trend of land desertification in Zoige County. [Method]The process of evolution dynamics of land desertification was studied with the transfer matrix of biostatistics based on the data of four land desertification monitoring data from1994,1999,2004,and 2009 in Zoige County. [Result]Desertification expansion was at a rate of 11. 08% per year in Zoige County during the period from 1994 to 2009,as a result,the sand area in 2009 was 4. 5 times higher than that in1994. The average annual rate of the expansion of desertification in diverse degrees of desertification was in a regular sequence of 24. 49%,12. 03%,7. 80% and 6. 68% for extremely severe desertification,mild desertification,severe desertification and moderate desertification land,respectively. On the whole,the degree of arenaceous desertification in sandy land was still in the initial stage for the mild sand land accounting for 75. 69% of the total desertification area,suggesting that it was the favorable period for the management of desertification. After 15 years of desertification evolution,the structure of different degree of arenaceous desertification had been changed with a trend of decreasing ratio of the moderate and severe desertification land and an increasing one of the mild and very severe desertification land in terms of desertification area ratio. The proportion of desertification degree remained stable,and that was 61. 53%,68. 77% and83. 06% for the period from 1994 to 1999,1999 to 2004 and 2004 to 2009,respectively. This proportion suggested thedesertification degree was in a gradually stabilized trend in time series. The sandy land area in mitigating desertification degree was 2. 23 times of the land area proportion in deterioration of desertification during the period from 2004 to 2009.The trend of sandy d

关 键 词：土地沙化 沙化程度 演变 特征 若尔盖高原 

分 类 号：S714.7[农业科学—林学]