近20年来西藏耕地与人口变化相关分析

Correlation Analysis between Cultivated Land Use Change and Rural Population in Tibet within Recent 20 Years

采用1981年～2001年的统计资料,用统计分析方法,研究了近20年来西藏耕地变化过程与地域分异特征,建立了耕地与人口相关模型,分析了西藏耕地与人口相关性变化趋势以及不同地区耕地与乡村人口相关的区域差异性,提出了劳耕密度的概念。结果表明:①近20年来西藏耕地面积呈现波动增加趋势,但增加速度缓慢,不同时段耕地年均递增率呈现低-负-高模式,耕地变化地域差异特征明显;②利用2001年耕地与对应的乡村人口数据建立了二者之间的E型指数曲线相关模型,发现耕地面积与乡村人口数之间存在着极显著的正相关关系;③由1981年～2001年西藏全区耕地面积与乡村人口数据建立的E型曲线模型,相关性虽呈正相关,但未达到0 05水平的差异显著性,且不同地区乡村人口数与耕地面积之间的相关系数在不同时期差别较大;④1981年～2001年期间,人均耕地面积减少了0 0301hm2,年均递减率为1 13%,而劳耕密度呈现增长趋势,净增加0 4943人 hm2,年递增率为0 64%,在不同时段人均耕地面积及劳耕密度的变化幅度及趋势不同。

Based on the cultivated land use survey data in 1981,1985,1993 and 2001,and by using statistical analysis methods,the spatial-temporal process and differentiation of cultivated land use change in Tibet were analyzed. Using the date of cultivated land use and rural population by county in 2001,a correlative model between cultivated land use and rural population was set up,and the usefulness and errors of the model were analyzed in 2000. The results indicate: 1) The total area of cultivated land-use increased with the elapse of time,but its speed was slower. The increased area was 16108hm^2,with 805.4hm^2 of annual average and 0.38% of annual average increased rate from 1981 to 2001. The annual increased area and rate were 2365.25hm^2 and 0.11% from 1981 to 1985,-933hm^2 and -0.05% from 1985 to 1993,and 7580hm^2 and 0.43% from 1993 to 2001,respectively; 2) During 1981 to 2001,the spatial-temporal feature of cultivated land-use change in the Tibet was very remarkable. By the annual average increased rate of cultivated land-use in 1981～1985,1985～1993 and 1993～2001,there were different increased courses in various areas away,with 'minus-high-minus' in the area of LaSa,'minus-minus-high' in the areas of ChangDu,NaQu and A Li,'high-high-high' in the areas of LinZhi,'minus-minus-minus' in the areas of ShanNan and 'minus-low-high' in the area of RiKeZe; 3) Due to the influence of rural population and policy,the increased rate were different between per capita cultivated land and labor cultivated land density from 1981 to 2001. The increased rate was 0.0307hm^2/p and 1.130% annual average increased of per capita cultivated land from 1981 to 2001,the increased rate was 0.4943P/hm^2 and 0.64% annual average increased of per labor cultivated density from 1981 to 2001;4) The formula of the simulated correlative model between the cultivated land use and rural population is E index curve. The result of its test and error analysis shows that the relation of plus correlation are very intimately between cultivated land use and rural population.