Rangeland Monitoring and Invasive Weeds

One of the serious biological obstacles that must be addressed in any comprehensive revision of rangeland ecological condition assessment is what to do with sites dominated by exotic self-invasive species. In certain cases such species have truncated succession so that with a bare minimum of disturbance, the sites will never return to dominance by native perennial species. Are such sites destined to remain always in what is defined as "poor" ecological condition. Many communities dominated by exotic annuals are closed to the recruitment of seedlings of native perennial species. At the same time the communities are open to invasion by other introduced species. Should susceptibility to future invasions be a criteria in assessing the ecological condition of rangeland communities. The sustainability of communities dominated by exotic invasive species is assessing the ecological condition of such communities. Deviation from the plant community concepts of range condition and trend judgement involves setting new benchmark standards. This is an endeavor fraught with many perils.     

内蒙古哈素海水质环境状况及其污染特点

本文根据１９９１年对内蒙古呼和浩特市哈素海的水质调查结果，分析和评价了哈素海水质状况及其污染特点。结论是哈素海水质仅符合《地面水环境质量标准》的第五类标准。其主要污染特点营养物质偏高，造成了湖泊富营养化。     

Rangeland Monitoring and Fire: Wildfires and Prescribed Burning,Nutrient Cycling,and Plant Succession

Prescribed fires are used to manipulate and manage rangelands, but effective monitoring techniques are needed to ensure that management goals and objectives are being met. The application of an effective fire program on rangelands is not a simple task. Overgrazing by livestock since the early development of the livestock industry has altered the vegetative complex on most rangelands with an increase in woody plants. Because of its relatively low cost, prescribed fire, both cool and warm season, are sustainable practices if proper grazing management is part of the management scheme. Grazing management and prescribed fire have often been treated as separate issues by rangeland managers; however, development and application of an effective prescribed burning program requires an understanding of the relationship between fire and grazing. Ranchers need fuel (grass) to burn and they also need income from livestock, which requires forage (grass, a major part of forage). In the short-term, fire reduces carrying capacity for livestock but, in the long-term, fire increases grass production, resulting in increased carrying capacity. Therefore, some monitoring technique is needed that will allow the manager to budget grass for both fuel and forage. The Grazing Manager (TGM) is a software program that projects both forage production (expressed as animal unit days) and, animal demand (expressed as animal unit days) for each forage year. TGM has been successfully used on the Texas A&M University Research Station at Sonora as a tool to integrate prescribed fire and grazing management.     

水环境质量综合评价方法的比较研究

本文利用西山湾水库多个水质监测断面多项指标的监测数据,依据《地表水环境质量标准》(GB3838—2002),通过理论阐述及实例分析,对模糊综合评价法、基于遗传算法的模糊贴近度评价法和基于遗传算法的逻辑斯蒂曲线评价模型三种评价方法进行了对比分析。结果表明:基于遗传算法的模糊贴近度评价法评价结果更趋合理。     

论生态环境与资源保护区的经营管理方法--2000年6月与选择性诺贝尔奖获得者Prof.Dr.Michael Succow考察新疆有感

本文通过对中德比较研究,论述了生物圈保护区、水源保护区等的经营管理方法,建议形成新的人生哲学、建立实用地理学。     

塔里木河水质评价研究

受人类活动的影响,塔里木河干流的水质受到不同程度的污染。水质评价结果表明,源流河水污染很轻,而流上,中游污染较重,干流下游由于有孔雀河水量加入,水质污染较上,中游稍轻。在监测指标中,主要是矿化度,硫酸盐和氯化物的超标率上升造成污染负比的上升。     

人工神经网络在水环境质量评价和预测中的应用

在人工神经网络在水质评价和预测方面的应用研究现状、发展趋势进行讨论的基础上 ,用人工神经网络和综合污染指数法 ( N.M.L.)对同一实例进行比较研究 ,结果看出人工神经网络的优越性 ,在用于水质评价和预测时适应性强 ,结果客观、合理 ,具有深入开发的研究价值和良好的应用前景 ,并可实现对水质变化进行预测和预警的目的。     

胡杨种子萌发和胚根生长对环境因子变化的响应

通过温度、水分、PEG和NaCl溶液对荒漠河岸树种胡杨（Populus euphratica Olivier.）种子萌发和胚根生长的影响研究,结果表明：胡杨种子在10～40℃时萌发率均超过50％;其种子能够在完全水分浸泡情况下萌发生长;在NaCl和PEG-6000溶液胁迫下,萌发率与水势呈显著线性负相关（R^2〉0．89）,并受到温度的微弱影响;水势对种子萌发和胚根生长的抑制作用,在高水势时,NaCl比PEG-6000溶液明显,而在低水势时后者超过了前者;在各种胁迫下,胚根生长都比种子萌发受到的抑制明显。实验结果显示,早期的低盐和充分的水分条件是胡杨幼苗存活的关键。     

三工河流域水量转换特征及水资源利用

三工河流域从源头至尾流经了不同的地质单元,在河流的不同地段上,水资源表现形式各不相同,或由地下水补给地表水,或由地表水给地下水。本文分析了不同地段上的水量转化特征,并在此基础上探讨了该区水资源利用现状,存在的问题,提出了有效的对策。     

控制病虫灾害提高森林质量

本文列举了森林病虫灾害造成森林质量低下的事实，提出了通过可持续治理挡制森林病虫灾害，提高森林质量的措施。     

Water use efficiency and photosynthesis of glyphosate-resistant soybean as affected by glyphosate

Previous studies comparing cultivars of different maturity groups in different soils demonstrated that early maturity group cultivars were more sensitive to glyphosate injury than those of other maturity groups. In this work, we evaluated the effect of increasing rates of glyphosate on water absorption and photosynthetic parameters in early maturity group cultivar BRS 242 GR soybean. Plants were grown in a complete nutrient solution and subjected to a range of glyphosate rates either as a single or sequential leaf application. Net photosynthesis, transpiration rate, stomatal conductance, sub-stomatal CO₂, carboxylation efficiency, fluorescence, maximal fluorescence and chlorophyll content were monitored right before and at different stages after herbicide application; water absorption was measured daily. All photosynthetic parameters were affected by glyphosate. Total water absorbed and biomass production by plants were also decreased as glyphosate rates increased, with the affect being more intense with a single full rate than half the rate applied in two sequential applications. Water use efficiency (WUE) was significantly reduced with increasing rates of glyphosate.     

岳普湖县水资源开发利用状况及发展方向

本文据野外实地考察和有关资料，论述岳普湖县水资源开发利用现状及存在的问题，探讨了水利发展方向及对策。     

水土保持专家系统的探索与试验

本文介绍了黄土地区水土保护专家系统的建筑原理与方法，系统采用压缩编码方式存贮各种地学图形与遥感图象数据，具有数据与图象的存贮更新，查询检索，分析处理，图象显示和自动制图功能，该系统可对黄土地区的土壤侵蚀进行快速，准确的预测，预报，并对水土流失的综合治理，水土保护规划提出几种可行性建议供用户选择，用该系统对山西省离石县王家沟流域羊道沟的土壤侵蚀进行了试验研究，并对试验结果进行了系统评价。     

沙质荒漠化土地评价指标体系研究

本研究根据我国沙质荒漠化 (亦称沙漠化 )土地现状评价与监测工作的需求 ,在实地调查的基础上 ,依据地表形态、植被、土壤三大特征 9项指标 (裸沙占地百分比、地表结皮、植被盖度、植被生物量、土壤有机质、全氮量、速效磷、速效钾、土壤物理粘粒含量 ) ,应用多元回归方法筛选评价指标 ,采用多因素综合指标分级数量化法建立了地方、区域、国家 3种尺度的沙质荒漠化土地现状监测评价指标体系。经三个不同气候区野外实地验证 ,结果表明 ,地方、区域、国家 3种评价尺度的判对率分别为 81 .0 3%、84.48%、89.66%。该指标体系具有实用性、可操作性、准确性高、简便易行、便于推广等特点 ,适用于我国各层次的沙漠化土地监测与评价 ,并有利于与国际接轨     

额济纳平原水资源特点与合理利用

水资源是额济纳平原生态环境恢复和绿洲稳定发展的决定性因素。本文根据额济纳平原不同形式水资源构成调查资料 ,分析了额济纳平原这个以河流补给为主的水资源系统的主要特点。通过对水资源的开发利用引起的环境变化分析 ,提出额济纳平原水资源的开发利用应以生态环境的恢复和建设为主要目标 ,要采取各种节水技术 ,合理的开发利用有限的水资源。     

水中12 种农药的固相萃取及GC-MS 测定方法研究

利用气相色谱法进行测定 ,用己烷和丙酮做洗脱溶剂 ,用 Isolute TMENV+SPE柱对水中 12种农药的固相萃取方法进行了研究 ,并用 MS选择离子模式进行了定量分析。水中添加浓度为 1、5、10μg· L-1三个水平 ,其中 11种农药的添加回收率在 6 2 .3%～ 10 5.0 % ,只有克百威的回收率较低。     

榆林市水资源可持续开发和利用研究

对榆林市水资源的基本特征和开发利用现状进行系统分析,通过科学合理的预测,提出了榆林市水资源可持续开发和利用的主要思路和途径。     

区域水资源可持续利用指标体系的设计及评价方法研究

通过对区域水资源可持续利用评价指标体系和方法的初步研究 ,设计出了包括水资源可持续利用综合指数 1个目标层、水资源量等 5个准则层和人均水资源量等 2 8个评价指标的层次性指标体系 ,并利用均方差权数决策方法 ,对区域水资源可持续利用进行全面分析和定量评价。     

和田河流域水文特征及区域水资源评价

1.和田河流域自然地理概况和田河流域地处我国新疆塔里木盆地中西部,东经77°40′-81°40′,北纬35°00′-40°30′。和田河水系发源于昆仑山北坡,是塔里木河水系中仅次于叶尔羌河和阿克苏河的第三大河。其上游有两源;东源玉龙喀什河;西源喀拉喀什河。两河在阔什拉什会合后,横穿塔克拉玛干沙漠腹地,在阿瓦提县肖夹克之西与叶尔羌河、阿克苏河相汇构成塔里木河,形成     

几种旱生植物盆栽苗木的水分关系和抗旱性排序

盆栽条件下,当土壤含水量逐步下降时;①植物的水饱和亏缺加剧,但不同植物间仍有差别;②植物水势趋于下降,其中旱生植物梭梭变幅最大,水势最低;③各植物的蒸腾强度均呈下降趋势,但旱生植物的蒸腾低于中生植物。在充分供水条件下,旱生植物苗木的生物量均大于中生植物,但梭梭例外,说明旱生植物苗木并非真正喜旱。对上述植物抗旱性的主分量分析(PCA)表明,其抗旱性从强到弱的顺序为:梭梭>山川柽柳>多枝柽柳>乔木状沙拐枣>头状沙拐枣>红果沙拐枣>沙枣>箭杆杨。并在二维主分量坐标上可将其分为三类。旱生植物苗木的主要抗旱途径为生理性抗旱,首先是有效的吸水能力,其次是完善的保水机制。