沙尘暴传输机理及源地环境特征

对沙尘暴的发生、传输机理及沙尘暴源地的环境特征进行了研究.结果表明,沙尘暴的发生与地理环境、地表土质、气候条件和地表植被状况等自然因素密切相关.裸露于地表的沙尘是形成沙尘暴的物质基础,降水稀少、空气干燥是沙尘暴发生的重要气候因素.地面上升的热气旋和大气的环流运动是地表沙尘暴发生和传输的动力.沙尘粒子的传输方式有蠕动、跃迁和悬浮3种.沙尘的传输距离和方向与大气环流的变化情况直接相关.沙尘暴源地一般位于大陆腹地,地域宽阔、平坦.地表土质多为沙砾、沙质土壤,地表土层裸露,土质干燥、疏松.沙尘暴源地的植被稀疏,气候的共同特征是全年降水稀少,空气干燥,冬季和春季大风天气频频出现.近年来人为的破坏活动也加剧了沙漠化的进程.     

石漠化治理对岩溶地下水水化学和溶解无机碳稳定同位素的影响

以贵州关岭-贞丰花江岩溶石漠化综合治理示范区不同土地利用类型和不同石漠化治理模式的5个泉点为研究对象,分析泉水水化学特征及溶解无机碳(DIC)稳定同位素(δ13CDIC)的分布和变化,揭示石漠化治理的岩溶效应和水质效应.结果表明,研究区地下水水化学类型为重碳酸-钙型(HCO3-Ca),人类活动干预相对较少的水井湾、戈贝和毛家湾泉水的水质较好,而受农业活动影响较多的吊井和谭家寨泉水主要离子浓度和电导率都较高,水质相对较差;泉水p H值、方解石饱和指数(SIc)和二氧化碳分压(p CO2)对土地利用或石漠化治理反应敏感,表现为水井湾、吊井、谭家寨和戈贝泉水中的p H值和SIc小于毛家湾泉水,相反p CO2明显大于毛家湾泉水;水井湾、毛家湾、戈贝泉水中的(Ca2++Mg2+)/HCO-3当量比接近1∶1,以碳酸风化碳酸盐岩为主,吊井和谭家寨泉水中(Ca2++Mg2+)相对HCO-3明显偏高,主要是因为受到农业活动强烈影响,可能有硫酸和硝酸参与了碳酸盐岩的溶蚀;此外,雨季由于生物旺盛,泉水中的δ13CDIC值较旱季偏轻;不同泉水中δ13CDIC平均值大小顺序为吊井(-12.79‰)水井湾(-12.48‰)戈贝(-10.76‰)毛家湾(-10.30‰)谭家寨(-6.70‰),反映了石漠化和农业施肥影响下的地下水的δ13CDIC值偏重,石漠化治理后泉水的δ13CDIC值则偏轻.     

云南水土流失与荒漠化初议

云南沙化灾害是水土流失、泥石流灾害引起的.长期的过垦过伐,毁林开荒,造成大量的水土流失、泥石流频发,也导致局部地区沙化土地的发生.但云南不会出现大面积的沙漠.     

黄河流域荒漠化协同防治与上、中、下游绿色发展

黄河流域在国家发展中具有重要的战略地位,但其生态系统脆弱,荒漠化问题突出,面临经济发展与生态环境建设双重挑战。本文从国家战略全局和全流域视角入手,分析黄河流域荒漠化现状及荒漠化治理存在的问题,提出了黄河流域荒漠化协同防治与全流域绿色发展的五大策略,即上中下游协同攻坚,打好黄河流域荒漠化防治与生态保护总体战;创新突破,建立黄河上游重要水源补给生态特区;积极布局推广荒漠化治理重大先进技术工程模式,多途径破解荒漠化治理难题;建立黄河流域绿色生态经济体系,实现人地关系协调、绿色循环高质量发展;多渠道融资,构建荒漠化治理资金保障长效机制。本文旨在为黄河流域上中下游统筹协调防治荒漠化,实现全流域绿色发展提供新思路。     

松嫩平原西南部土地碱质荒漠化预警研究

土地荒漠化是一个全球性的环境问题,其造成的资源丧失和环境破坏给人类带来了严重的危害,成为影响深远的缓发的生态环境灾害.笔者以松嫩平原西南部为例开展荒漠化预警研究,将地理信息系统与人工神经网络模型相结合,实现了对荒漠化发生的定位、定性及定量研究.      

Native Seed Collection and Use in Arid Land Reclamation: A Low-Tech Approach

Loss of vegetation production in arid lands has been difficult to remediate and has signifi- cant economic impacts on human populations. Restoration efforts based on non-local materials and large-scale mechanization have not been capable of efficiently reversing the trend of environmental degradation. The use of traditional knowledge and simplified methods of seed harvesting, storing, marketing and soil preparation have proven that regeneration of native species and efficient land reclamation is possible in areas that have traditionally been considered degraded beyond redemption. This paper describes a method of land reclamation that combines tradition and simple mechanics that can be applied in all arid areas that face desertification. Because the work builds on cultural practices long used in non-industrialized societies, it is particularly adapted to rural areas. The methods described have the potential to open new low-tech economic opportunities to all segments of local non-urban populations while combating desertification and creating a more ecologically sound environment.     

Community Production Practices and Desertification in the Sahelo-Sudanian Region of Cameroon at the Turn of the Millennium

The Sahelo-Sudanian region of Cameroon extends over 10 million hectares. Varied flora and soil types, a complex mosaic of vegetation and plant communities and a diversified wild animal population are the major natural resources of this region. Desertification in the region can be related to two major known causes: a. short or long-term drought due to short-term or long-term climatic trends toward aridity; b. human activities which degrade the biological environment. Globally, humans generally have less effect on desertification than climatic change in the short run. The only strategy to fight against this situation particularly in the developing countries is to withdraw populations from the areas and to settle them elsewhere. However, most local or regional desertification processes in general, and in the Sahelo-Sudanian region in particular, are due to the misuse or unsound exploitation of natural resources by humans and their animals. Often, comprehension of the complexity of even small interactions between parameters affecting our local environment remains limited. Poor economic assessments of the long-term benefits of proper natural resource conservation and management increase the extent of the exploitation, in turn increasing the degradation process. Yet ecologically sound management of natural resources integrating indigenous knowledge and basic population interest and concern can secure restoration in several areas and sustained productivity of Sahelo-Sudanian lands.     

The Role of Soil Surface Crusting in Desertification and Strategies to Reduce Crusting

Soil crusting decreases infiltration, increases erosion, and impedes vegetation establishment, so reducing the impact of crusting is of major importance in combating desertification. Although surface crusting has been the subject of considerable research over the past 50 years or more, the practical management of soil crusts remains a challenge for many dryland communities. Crusting occurs in two steps, an initial aggregate breakdown period that occurs under rainfall and a subsequent hardening phase during drying. Several factors influence crust development, but the single most important one is soil aggregate stability. Strategies to reduce crusting can be based either on protecting the surface from raindrop impact or improving aggregate stability, or a combination of both. However, crust control is labor and/or capital intensive and must be thought out clearly in terms of the benefits to be achieved.     

大力加快生态建设步伐努力推动鄂尔多斯荒漠化治理进程

加强生态建设，是推动荒漠化治理进程的有效之策。文章从荒漠化的概念以及造成荒漠化的原因，分析了鄂尔多斯市荒漠化的现状。提出以生态建设为出发点，治理与开发并重，走生态建设-可持续发展-更加富裕的路子。     

基于GIS和RS的雅鲁藏布江中游地区荒漠化动态变化研究

选取1988年TM、2000年ETM以及2007年的ALOS影像数据为主要数据源,对雅鲁藏布江中游地区荒漠化动态变化进行了研究。结果表明:近20年沙质荒漠化经历了1988—2000年沙质荒漠化总面积呈上升趋势和2000—2007年沙质荒漠化总面积呈下降趋势两个发展阶段,但是总体上却是呈上升趋势,其中轻度、中度和重度沙质荒漠化土地增加的速度分别为1.93%、1.50%和3.20%,表现为沙质荒漠化土地总面积在较大幅度增加的同时荒漠化程度的提高速度相当快;沙质荒漠化的形成,一方面与青藏高原高寒干燥的气候和脆弱的植被生态系统有关,另一方面也受人为活动的驱动。该研究可为该地区荒漠化治理提供科学依据。