【作者】 柴成武；

【导师】 蒋志荣； 徐先英；

【作者基本信息】 甘肃农业大学 ， 水土保持与荒漠化防治， 2006， 硕士

【摘要】 随着荒漠化研究由定性到定量的发展,不断借鉴新的研究方法、手段进行荒漠化定量研究已成为必然趋势。应用因子分析法的指标提取及压缩优势进行土壤质量分析、荒漠化现状评价、研究荒漠化影响因子;应用分形方法研究土壤质地;应用hurst指数进行荒漠化发展趋势预测就产生在该背景下。本文通过研究区荒漠绿洲过渡带土壤质量及荒漠化现状评价两个层次的分析,探讨了研究区土壤质量空间和垂直梯度上的变化特点,确定了研究区荒漠化空间的荒漠化类型、程度及“荒漠—绿洲”方向上荒漠化类型、程度的变化规律;通过研究区荒漠化影响因子的分析,定量地说明了荒漠化影响因子的贡献率;以1989—2003年的年人口数据、年末耕地面积数据、农村用电量数据、年末机电井眼数数据对其未来10年的变化趋势分别作了预测;以1963—2003年的年沙尘暴日数资料对未来10年沙尘暴的变化趋势作了预测。研究结果如下:(1)土壤质量变化特点:研究区土壤质量随沙质荒漠化或盐渍荒漠化的进一步发展,表现出不同的质量水平。垂直梯度上,第一土层与第二土层受外界影响较大,在不受外界干扰的情况下,表层肥力高于第二层,如果与该规律相反,则表明受吹蚀影响较大;从第二层开始,土壤质量越来越高,直到达到最大值,然后开始下降,最大值出现的土层深度即最大值拐点与土壤质地所导致的淤底层出现深度有关。同层土壤空间水平上,在研究区空间范围内,横向方向上随绿洲向荒漠过渡,土壤质量依次降低;纵向方向上从民勤西南到东北,土壤质量有增高趋势。土壤质地表现为沙地土壤粒级组成主要集中于1—0.10mm的粗沙和0.10—0.05mm的中中细沙两个部分,而且以集中于1—0.10mm的粗沙占主体;土壤分形维数大都保持在2.8左右,各粒级颗粒均匀度不高,粗沙与中细沙两极分化严重;同一样点不同土层分形维数没有明显区别。(2)荒漠化评价:选择表达土壤物理性质、化学性质、植被状况的土壤容重、有机碳、全氮、电导率、酸碱度(pH值)、植被盖度、植被种类、植被生物量、土壤粒径小于1mm、0.1mm、0.05mm的土壤机械组成以及地下水位用因子分析法进行分析,结果表明:民勤县西南为重度沙质荒漠化区,中部为轻度盐渍化区,东北部为极重度盐渍化区;沿绿洲—荒漠方向荒漠化有“加剧—减轻”趋势。(3)荒漠化影响因素:分为定性分析和定量分析两个层次。定性分析从民勤县外部人为活动和内部人为活动的水资源利用、植被保护与土地利用、土地利用方式变化、人口及畜牧业压力、气候变化等方面进行分析,认为民勤现代荒漠化主要体现为以反复垦殖、弃耕、过度水资源利用为主导的荒漠化,滥牧、滥伐只是过去的行为,气候在近几十年来更多还原

【Abstract】 With the development of study of desertification from qualitative examination to quantitative study。It was sure a trend of quantitative study for desertification by using some new way for reference. At the back of which, studied the soil fertility, evaluated the present situation of desertification, analyzed aspect of desertification with the extraction and condensation advance of factor analysis for index; also studied the soil texture with fractal demission and development of trend of desertification with Hurst-index.(1)The character of soil quality: It presented a different quality with the development of sand desertification or salinization in Minqin. In the vertical gradient, the first depth was higher than the second if it was not disturbed or it should present opposition by blastation, from the second to the sixth the soil quality became higher and higher until it get the best, then it should descend and the depth of the best was connected to the depth of deposition of clay. In the level space of the same depth the soil quality went down from oasis to desert and went up from South-west to North-east of Minqin. The soil texture presented main body of 0.1-1mm of coarse sand and 0.05-0.1mm of thin sand, 0.1-1mm especially, the soil dimension remain about 0.28. The soil texture was not even and the fraction of coarse and thin divided severely, but the soil dimesion was discriminating for different depth of the same spot.(2)Evaluation of desertification: Analyzed bulk weight、organic carbon、total nitrogen、electric conductivity、potential of hydrogen、vegetation cover、vegetation type、biomass、fraction of less than 1mm、0.1mm and 0.05mm、low ground water level by factor analysis from aspect of soil physical and chemical character, also from vegetation, the result showed that the South-west of Minqin included in severe sandy desertification area,light alkali-salinity in middle area and severe alkali-salinity in North-East area; There are trend of getting severe and then getting light for desertification from oasis to desert.(3)Factor of desertification: This was described in qualitative examination and quantitative study. Through analyzing of external human activities and internal human activities of using of water resource、plant protection and ways of land use、type of land use、population and graziery pressure、variance of climate in qualitative examination,draw a conclusion that the process of desertification was bodied by the action of reclaiming and cultivating、giving up cultivating、overuse of water resource; Excessive hag and overstocking was the deed of past更多还原