我国荒漠化地区土地退化的防治措施

该探讨了荒漠化的定义及我国荒漠化危害，从荒漠化过程监测、生物措施稳定性、荒漠化治理综合效益、荒漠化土地造林技术和荒漠化的防治途径方面进行了研究和探讨，并对今后我国荒漠化防治工作提出了几点建议。     

我国沙尘暴灾害初步研究

2000年北京地区发生了12次沙尘暴、扬沙和浮尘天气，这是全国引起强烈反响。据建国50年来全国67773条气象站沙尘暴记录分析认为，我国沙尘暴易发区域广泛，但多发区集中在我国西部，与荒漠化状况相近；70年代前沙尘暴有增无减，但因当时人们生态环境意识薄弱并未引起足够重视；70年代是我国沙尘暴发生频率最高时期，80－90年代局部和小范围沙尘暴发生次数逐渐减小，强度有所减轻。但随着区域经济的发展，沙尘暴灾害损失日趋增大。建设林草植被、改善生态环境对减小局部和小范围沙尘暴发生次数及灾害程度具有重要作用。     

宁夏地区荒漠化现状与治理对策

介绍了宁夏地区荒漠化问题的现状,论述了荒漠化的成因,指出了相应的治理对策及其今后应着力研究和开发的关键技术.     

石羊河下游农户对生态退化的感知及响应

石羊河下游生态环境日趋恶化,严重影响和制约着该流域的可持续发展,急需寻求有效的响应策略。本文基于农户调查数据,运用多元回归方法分析了石羊河下游农户对生态退化的感知及响应策略。结果表明:农户对水资源紧缺感知最强烈,对沙尘暴频发感知度次之,对土地荒漠化和盐碱化的感知度较低;坝区、泉山区和湖区农户对水资源紧缺和土地盐碱化的感知强度依次增加,对沙尘暴发生频率的感知强度依次降低;坝区、泉山区、湖区的水资源紧缺响应策略多样化指数和土地盐碱化响应策略多样化指数依次增加,湖区土地荒漠化和沙尘暴的响应策略的多样化指数最高,泉山区土地荒漠化的响应策略的多样化指数最低;不同区域农户对生态退化的响应措施各异,生计资本和农户对生态退化感知度对响应策略有显著影响。结合研究区域的生态和社会经济状况,对上述结果进行了深入的剖析,并在此基础上提出了改善当地生态退化的建议。     

松嫩平原水资源可持续利用战略探讨

分析了我国北方荒漠化形势和实施农田保护性耕作对防止沙尘暴的作用和意义。根据生态学原理,提 出了加强农田防护林建设和实施留茬、免耕、覆盖等保护性耕作技术措施以及加强农田防沙配套技术体系研究 的一些设想。     

石羊河流域生态环境恶化原因及综合防治思路与措施

石羊河流域生态环境日益恶化，其主要特征是土地荒漠化，导致沙尘暴频繁发生。石羊河流域土地荒漠化的原因有自然因素和人为因素，由于自然因素和人为因素的共同作用，加剧了流域生态环境的进一步恶化。在分析原因的基础上，提出了合理利用和保护水资源；完善土地荒漠化防治的有关法规；制订优惠政策，鼓励全民进行综合防治；开展科学研究，探索科学合理的土地荒漠化防治模式的对策及建议。     

河西走廊生态环境治理与保护

针对河西走廊地区目前存在的生态环境恶化现象,重点阐述并分析了土壤盐渍化、土地沙化、荒漠化以及沙尘暴等问题,并在此基础上提出了合理利用水资源、提高生态工程质量、加强自然环境保护及协调人与环境的关系等几项保护与改善措施。     

石羊河流域荒漠化评价指标体系研究

石羊河流域作为西北干旱区内陆河流域生态退化的典型,因其特殊的地理位置,成为我国北方沙尘暴的重要源地之一,影响到整个北方地区的天气状况。本研究在建立解译标志的基础上,对1999年和2004年两期卫片进行比较,并到现场进行重点核实,首次建立了石羊河流域荒漠化评价指标体系,结果表明石羊河流域荒漠化面积呈发展趋势,而且从程度上来说,向两极发展,即极重度、轻度面积增加,中度和重度面积减少,这与有关专家的预测和实际情况基本一致。     

石羊河下游民勤绿洲荒漠化影响因素趋势预测

 从荒漠化治理的实践出发,用Hurst指数对内陆河下游民勤绿洲荒漠化影响因素进行预测分析,对体现民勤绿洲荒漠化主要影响因子的农村人口、耕地面积、农村用电量、机井眼数和沙尘暴时间5个指标进行预测。结果表明:未来10年内,农村人口Hurst指数为0.381,与1989—2003年的上升趋势相反,具有下降趋势;年耕地面积Hurst指数为0.578 3,与1989—2003年时的上升趋势一致,但持续性不强;农村用电量Hurst指数为0.3324,与1989—2003年的上升趋势相反,具有下降趋势;年机井眼数Hurst指数为0.2618,与1989—2003年的上升趋势具有较强的长期相关性,但为相反趋势;年沙尘暴时间Hurst指数为0.4043,呈与1953—1998年的下降趋势相反的弱持续相关性。通过预测认为:应该加强对耕地面积的宏观调控,抑制土地利用所引起荒漠化的发展,控制开荒,提高现有耕地的利用效率;同时要继续宏观调控农村人口、农村用电量、机井数量变化向良性方向发展。     

农牧交错带土壤及表生植被某些特性变异与荒漠化的相关性——以冀北康保县为例

农牧交错带因特有的自然条件,体系稳定性差,自调能力弱,平衡易破坏,生境十分脆弱。虽然近20年大风与沙尘暴平均次数有所减少,主要气候要素趋向良性,但因人畜增长,人为过度垦、牧、樵等负面活动强化,导致该区表层土壤颗粒粗化,有机质含量降低,植被覆盖度下降,植物群落结构变异、退化,土地荒漠化加重。由此表明:该区土壤及表生植被的某些特性变异与荒漠化十分相关。     

LANDSAT IMAGES REVEAL TRENDS IN THE AEOLIAN DESERTIFICATION IN A SOURCE AREA FOR SAND AND DUST STORMS IN CHINA'S ALASHAN PLATEAU (1975–2007)

The development and reversal of aeolian desertification have been widely recognised as the dominant causes of changes in the source areas of dust storms. The Alashan Plateau, which is near China's Hexi Corridor, is one of the major dust storm source regions in northern China. To investigate the relationship between climatic and anthropogenic factors and the development of aeolian desertification, we reconstructed the temporal and spatial evolution of aeolian desertification and the underlying processes from 1975 to 2007 using Landsat images and analysed the driving forces. The results show that aeolian desertified land in the study area covered 32 847·79 km² in 2007, amounting to 11·3 per cent of the total area, with an initial period of desertification expansion from 1975 to 2000 and a reversal of desertification from 2000 to 2007. On the basis of the analysis of effects of climate changes and human activities in the region, aeolian desertification was principally driven by human activities in this area; climatic variations had little effect on the area of severe desertification. Copyright © 2011 John Wiley & Sons, Ltd.     

土壤水分与氮肥对玉米根系生长的影响

利用田间小区试验研究了不同土壤水分条件下N肥对根系生长（根长、根重和根冠比）的影响。结果表明,玉米拔节期和开花期无论水分条件如何。施N肥可增加其总根长、麦层根长和根重并使根冠比下降;灌浆期施N肥可增加总根长和表层根长,但正常水分条件下N肥使根重和根冠比下降,而干旱条件下N肥对根重和根冠比则无影响,不同处理根冠比大小与N吸收和分配有很大关系。     

河北省风蚀沙化与防治

风蚀沙化现象在河北山区普遍存在 ,在 2 0 0 0年的沙尘暴中扮演了重要的角色。分析了河北省风蚀沙化的原因 ,结果认为是干旱和人类不合理的生产活动造成了植被的严重破坏 ,发展为风蚀沙化。提出了防治沙化的 5大措施 ,即增加人工降雨改造利用沙地、发展灌溉农业提高水资源利用率、治理水土流失、优化种植结构、立体开发、建立健全监测预报系统。     

基于RS和GIS的甘肃省沙漠化现状及潜在沙漠化程度评价

通过对1986,2000年两期TM图像的解译,获得甘肃省14年间土地利用与土地沙漠化变化情况.通过GIS,建立了甘肃省土地沙漠化与土地沙漠化潜在程度数据库.利用沙漠化发展指数与主成分分析法,进行了甘肃省土地沙漠化发展与潜在沙漠化程度空间格局分析.研究表明,甘肃省沙漠化发展规模呈现河西走廊大于东部其他地区.但是,东部总体沙漠化发展程度要强于河西走廊地区.由于受沙漠化致灾因素的影响,潜在沙漠化程度的空间格局基本与沙漠化发展规模空间格局一致.     

中国北方农牧交错区研究展望

近年北京和华北地区的沙尘灾害天气引起了广泛关注,其上风向地区的农牧交错区不但是防护的重要屏障,也是沙尘的源地之一。为了减轻农牧交错区本身的生态压力和环境恶化,需要明确其范围、界线、发展历史和治理方式。综述了上述中国北方农牧交错区的研究进展,并展望了农牧交错区研究中比较紧迫的区域和研究方向。在研究的领域当中,荒漠化及物质迁移仍然是持续研究的基础,景观（土地利用）变化及其模拟和水土保持等生态恢复研究是针对性较强的研究内容;在农牧交错区中,河北坝上地区和内蒙古乌盟后山、长城沿线、毛乌素和科尔沁等农牧交错地带是重     

阿拉善地区沙尘暴发生的时空变化规律探讨

统计分析阿拉善地区1961-2003年43a的沙尘暴发生的空间分布特征,月际、年际和年代际的时间变化特征及其原因。结果表明：阿拉善地区沙尘暴天气在空间分布上以拐子湖为中心向外辐射减少,且北部、东部区域沙尘暴发生多,西部、南部区域发生少;在季节变化上呈现出沙尘暴春夏多发、秋冬少发的分布规律,年际间沙尘暴发生时间（以d计）高于多年平均发生时间的年份少,年代际间则以20世纪70年代沙尘暴发生时间最多,之后表现为逐渐减少趋势;沙尘暴出现时间是该地区特定气候、地理和生态环境等条件的反映,沙尘暴发生时间与大风发生时间呈正相关。与当年气温、上年降水量呈负相关,且月均沙尘暴发生时间与月均大风发生时间呈紧密的线性正相关关系,相关系数达0．9885。研究结果可为阿拉善地区沙尘暴的防治提供科学依据。     

Chemical Composition Change in TSP Due to Dust Storm at Gosan, Korea: Do the Concentrations of Anthropogenic Species Increase Due to Dust Storm?

Aerosol composition change between dust storm and non-dust storm periods in spring is studied using the total suspended particle data measured at Gosan, a background area in Korea. The concentrations of eight inorganic ions and 12 elements were analyzed for the TSP samples collected from March 1992 to May 2006. Two-step statistical analyses were carried out for the data: F test and t test. The concentrations of anthropogenic ionic species showed increasing trend since 2003. The absolute concentrations of most anthropogenic species such as sulfate or nitrate increased (from 7.33 to 9.25 µg m^?3 and from 2.04 to 4.84 µg m^?3, respectively) during the dust storm period. However, the enrichment factors or normalized concentrations based on Al of most anthropogenic species decreased during dust storm period (factor of 0.1–0.5). It suggests that, in general, relative importance of anthropogenic species during dust storm would be not high.     

Transport of polycyclic aromatic hydrocarbons through a partly urbanized river basin

The PAH-pollutant loads resulting from storm runoff to a receiving stream are associated with high concentrations of suspended sediments. This is explained by the sorption coefficients and isotherms on street dust, suspended solids, bedload and other sorbents. Pollutographs for a stream with storm runoff mainly from storm water overflows from a combined sewered medium sized town show strong ‘first-flush’ phenomena. Rainfall and bedload contribute only to a lesser extent to the overall transport which stems from street dust washoff. High correlation between total PAH load and maximum flow, but no relation between total PAH load and the number of days since the previous storm, indicates a ‘low washoff case’ under ‘transport limited’ conditions. 3.4-Benzopyrene load was modeled by a pollutant washoff function analoguous to that of the EPA storm water model.     

A New Approach for Understanding Lead Transfer in Agricultural Soil

A multi-stage particle sampling instrument and a particle counter were operated at the ground monitoring site in Fukuoka where was directly exposed to the outflow of air masses from the Asian continent during the springtime of 2005. The bulk and individual dust particles were analyzed simultaneously by ICP-MS and micro-PIXE, respectively. The ground-based observation of dust storm by the Japan Meteorological Agency and by the NOAA HYSPLIT dispersion-trajectory model indicated that dust storm was driven from the Chinese continent including dust source area. The number concentration of gigantic particles (e.g., larger than 5 μm) was measured to be 10 times higher in an Asian dust storm (hereafter called “ADS”) period than in a non-ADS period. There is an outstanding increase of mass concentration in the range of 3.5–7.7 μm in ADS event. In ADS event, soil fraction accounts 57.9–70.1% of particle mass concentration in coarse particles larger than 3.5 μm. Micro-PIXE analysis enables us to classify individual dust particles into several types. The particles with 3.5–5.1, 5.1–7.7, and 7.7–10.9 μm experienced aging processes by 60.6, 69.2, and 77.2%, respectively. On the basis of the reconstructed elemental maps by micro-PIXE analysis, the chemical transformation of dust particles was also presumed.     

拐子湖地区沙尘天气风蚀起沙量的估算

为研究沙尘暴中心在沙尘天气下风蚀起沙量和一些参数的具体情况,以巴丹吉林沙漠拐子湖地区一次沙尘天气过程为例,通过经验公式与野外仪器观测对比分析,对拐子湖地区风蚀起沙过程的一些参数进行了分析。结果表明:摩擦速度与风速成正相关,并影响着风蚀起沙量变化;临界摩擦速度为0.36m/s;估算了平均顺风向沙尘通量和垂直沙通量分别为1.7E-02kg/(m.s)和1.38E-07kg/(m2.s),顺风向沙尘通量要远大于垂直沙通量。这些参数的得出对防风治沙有着重要的意义。