宁夏1999—2009年土地荒漠化演变影响因素分析

Analysis on the Factors Influencing the Evolution of Desertification in Ningxia of China from 1999 to 2009

利用宁夏1999、2004年和2009年荒漠化土地监测数据,对宁夏土地荒漠化的演变趋势和影响因素进行分析。结果表明:1999—2009年间,宁夏荒漠化土地面积呈递减态势,由320.74万hm2减少至289.88万hm2,逆转趋势明显。其中水蚀荒漠化和风蚀荒漠化土地明显减少,风蚀荒漠化土地面积由151.91万hm2减少至134.58万hm2,水蚀荒漠化土地面积由165.72万hm2减少至148.97万hm2;盐渍化土地明显增加,由3.11万hm2增加至6.33万hm2。荒漠化程度明显减轻,重度、中度荒漠化土地面积明显减少,轻度荒漠化土地明显增加。重度荒漠化土地面积由100.98万hm2减少至27.57万hm2,中度荒漠化土地面积由142.70万hm2减少至138.38万hm2,轻度荒漠化土地面积由71.0万hm2增加到117.08万hm2。荒漠化地区植被状况进一步改善,植被盖度逐渐增加。国家政策项目支持、荒漠化土地综合开发利用、各类生态保护政策机制的制定完善和社会力量参与荒漠化防治等人为因素对荒漠化逆转产生决定性的影响,气候变化所产生的不利影响被上述因素所产生的有利影响所抵消;人口压力、历史人为不合理活动和水资源低效利用等人为因素在一定程度上减缓了宁夏荒漠化的逆转趋势,将成为宁夏未来荒漠化防治过程中需要重点克服的不利因素。

With the desertification monitoring data in 1999, 2004 and 2009 in Ningxia, we analyzed the evolution of the desertification and its influencing factors in Ningxia. The area of desertification land decreased from 3. 2074× 106 hm2 in 1999 to 2. 8988× 106 hm2 in 2009 and reversed obviously during 1999--2009. The area of wind-erosion desertification land decreased from 1. 5191 × 106 hm2 in 1999 to 1. 3458 × 106 hm2 in 2009, and the area of water-erosion desertification land reduced from 1. 6572× 106 hm2 in 1999 to 1. 4897×106 hm2 in 2009, while the area of saline desertification land increased from 3.11× 104 hm^2 in 1999 to 6.33 × 104 hm2 in 2009. The area of severe and moderate desertification land decreased obviously from 1. 0098× 106 hm2 and 1. 4270 × 106 hm2 respectively in 1999 to 2. 757 × 105 hm2 and 1.3838× 106 hm2 respectively in 2009, while the area of slight desertification land increased obviously from 7.10× 10s hm2 in 1999 to 1. 1708 ~ 106 hm2 in 2009, so desertification degree weakened obviously. In desertification regions, vegetation cover was improved further and vegetation coverage increased. Among the climate and human factors affecting the evolution trend of desertification, the reversion of desertification was influenced decisively by national policy, comprehensive development and utilization project, establishing and perfecting of various ecological protection measurement and mechanism, public participating in combating desertification, and so on. The negative effect produced by climate change was offset by the positive effect of these human factors. However, the reversion of desertification was slowed down to some extent by the population pressure, the human unreasonable activities in historical period, the inefficient utilization of water resources, and so on. These human factors are the unfavorable factors in combating desertification, which needed to be overcome in the prevention and control of desertification in Ningxia in the future.