地下水位对农业用水量变化响应的模拟研究

我国北方地区农业用水占实际取水总量的80%以上,地表水资源匮乏,地下水成为除降水之外的唯一灌溉水源.农业用水与地下水位的变化密切相关,被认为是引起地下水位持续下降的最大诱因.因此,研究地下水动态只有与农业用水结合才更有意义.本研究将DSSAT和MODFLOW两个不同尺度模型耦合,将作物用水与地下水直接建立关系,屏蔽了复杂的包气带水分运动过程,模型达到了很高的精度.通过对华北山前平原区2000年和2001年的模拟分析表明,农业用水节水28.36%,印减少抽取地下水118.75ram的情况下,才能停止本地区地下水位下降.     

毛乌素沙地神木县沙区农业生态系统限制因子分析

介绍了毛乌素沙地神木县沙区的概况,包括行政区划、地貌特征、植被类型,分析了该区农业生态系统非生物生态因子,发现水和土壤是该生态系统的主要限制因子,最后提出了农业生态系统水因子和土壤因子改善改良措施,采取第四系松散层孔隙潜水可满足该农业生态系统用水需求,且不影响生态用水,使用砒砂岩与沙复配成土的核心技术可有效改良土壤,提高该沙地农业生态系统生产力。     

Changes in large-scale patterns of plant biodiversity predicted from environmental economic scenarios

In the industrialized world large sums of money are spent on measures to preserve biodiversity by improving environmental quality. This creates a need to evaluate the effectiveness of such measures. In response we devel oped a model, NTM, that links plant biodiversity to abiotic variables that are under human control. These vari ables are: vegetation management, and the soil variables groundwater level, and nitrogen availability. We used species richness and the criteria of the Red Lists, i.e., the rarity and decline per species as measure for potential changes in biodiversity. NTM uses a statistical approach, and models potential plant biodiversity based on the above criteria as a non-linear function of the three soil variables. The regression model is calibrated on a data set consisting of 33,706 vegetation relevés. Because field data of vegetation combined with measurements of soil variables are insufficiently available, we used the average of Ellenbergs indicator values of the species in each relevé as a proxy. NTM was subjected to both validation and uncertainty analysis. The validation was car ried out by comparison with an independent data set. The uncertainty analysis showed that uncertainty in abso lute biodiversity values is large, but that comparative scenario studies can be carried out with an acceptable uncertainty. As an example we show the evaluation of the impact of three European economic scenarios on po tential plant biodiversity in the Netherlands. Although there were differences per vegetation type and per region, potential plant biodiversity had a tendency to increase, with the highest increase for the scenario with the highest reduction in atmospheric deposition of nitrogen and acidity.This revised version was published online in May 2005 with corrections to the Cover Date.     

GENESIS OF SOIL ALKALIZATION WITH SODIUM CARBONATE IN HOHHOT PLAIN

<正> Hohhot Plain, lying in the front of the Yingshan Mountains in inner Mongolia, isbounded by the mountain north, the Yellow River south, the Manhan Mountain east andloess hills southeast. Being 986 to 1100 meters above ses level, the plain generally slopesdown to the southwest, just in accordance with the flowing direction of the Great Heihe Riv-er and the Small Heihe River.     

地下水不同灌溉时间对水稻生长发育及产量的影响

对土质、肥力、面积相同的两块水田地分白天、晚间两个时间进行地下水灌溉试验。结果表明,白天灌地下水对水稻的生长发育和产量有较大影响,其中分蘖始期延迟5d、有效分蘖期延迟6d,最高分蘖期延迟6d,抽穗期延迟4d,成熟期延迟4d,产量降低5.1%。     

地下水人工回灌经济效益分析浅析

地下水人工回灌具有悠久的历史,人工回灌地下水的方法可分为两类:一是直接补给法,即把补给水源直接输送到地下水含水层中;二是诱导补给法,即除了达到自身的主要目的以外,还能对地下水起到诱发补给效果的方法。但每种方法都各有其特点和适应条件,要选择合适的地下水人工回灌方法,就必须对地下水人工回灌工程经济效益进行科学评价,这是保证回灌方案科学合理、回灌工程经济可行的必要前提。但目前地下水人工回灌效益研究往往是单方面的分析与评价,缺乏综合、系统的分析,提出的人工回灌经济效益包括7个方面:增加供水效益、扬程效益、减少新建水源工程效益、水质效益、增产效益、洪水控制效益和防治咸水入侵效益,并针对各种效益提出了相应的计算方法,完善了地下水人工回灌经济效益分析理论与计算方法,对于地下水人工回灌工程的可行性分析,实现地下水资源的可持续开发利用,改善生态环境,具有重要指导意义。     

Demand management of groundwater with monsoon forecasting

This paper presents an operational approach to setting prices for groundwater in accordance with the interannual variability of monsoon rainfall and the dynamic cost of groundwater use to society. The pricing system is designed for the state of Tamil Nadu, India, where groundwater is largely unregulated and the electricity for pumping is heavily subsidized. Depletion of aquifers during the primary growing season causes environmental damage and drying of wells. The proposed price-setting system estimates the marginal social cost of groundwater use based on the current state of aquifer storage and the forecast of the coming monsoon. Prices are set prior to onset of the monsoon so farmers can plan crop rotations according to the expectation of seasonal rainfall as reflected in the pricing signal. During years that forecasts accurately characterize the probability distribution of monsoon outcomes the market signal encourages economically efficient use of the resource. When monsoons differ from the expected outcome farmers are cushioned by ancillary effects of the pricing system.     

涉县地下水质量现状评价

为科学把握涉县地下水水资源条件,利用2012年涉县水质监测点数据,采用单组分和多组分质量评价方法,对涉县地下水质量状况进行了评价.评价结果表明,涉县地下水主要超标项目为NO3-、Fe、总硬度、耗氧量、SO42-、NH4+、F-,超标率分别为71.4％、7.1％、7.1％、7.1％、3.6％和3.6％;地下水水质主要由良好区、较好区和较差区组成,分别占研究区的35.47％、5.01％和59.52％.     

2014年赤峰市地下水位监测评估分析

概述了2014年度赤峰市气候特点,并对2014年度该市地下水位变化进行分析.结果表明,2014年赤峰地区气温偏高,光照正常,降水偏少,平均地下水位呈下降趋势,地下水位平均值为14.74 m,较2013年平均下降0.49 m,翁旗下降最多,为1.70m,仅敖汉旗较2013年上升了0.08 m,其余地区下降了0.12～0.84 m.针对赤峰市气候特点,地下水位正在逐年下降,建议各地区积极采取相应措施,因地制宜、开源节流、合理利用和保护地下水资源.     

人工神经网络预测尾砂充填对地下水中锌含量影响

[目的]研究了人工神经网络预测尾砂充填对地下水中Zn含量影响的可行性.[方法]采用误差反向传播神经网络(BP神经网络),建立了充填体放置时间、不同来源地下水水样、浸泡时间与重金属Zn含量之间的动态模型,预测广西某金属矿山全尾砂胶结充填体试块对地下水Zn含量的影响.[结果]当网络隐含层层数为1、节点数为7时,建立的BP神经网络预测模型能够较好地预测全尾砂胶结充填对地下水重金属Zn含量的影响.[结论]该研究为地下水环境的保护和矿区尾砂的安全处理处置提供了科学依据.