地下水源保护区划分原理及其在龙口市城市供水水源地中的应用

介绍了地下水源保护区划分方法以及解析单元法基本原理,以地下水流运移至水源井的时间长短为标准,利用解析单元法对龙口市的2个地下水源地进行了保护区划分,并针对不同级别保护区提出了地下水保护的具体措施。对龙口市今后制订地下水资源管理、土地利用、环境保护及城市规划等政策措施具有重要的指导作用。对其它地区地下水源保护区的划分具有一定借鉴作用。     

旱地春小麦集雨补灌增产机制初探

为查明集雨补灌对不同种植模式小麦的增产机理，于1998年在甘肃中部旱农区进行了田间试验。结果表明：少量灌水使沟播春小麦出苗率提高，小穗数及穗粒数增加；在植株生长的需水关键期补灌，小麦叶面积增大，叶绿素含量提高，地上部干物质及籽粒干物质积累量增加，有效小穗数及穗粒数增多，穗粒千重及千粒重增大，最终经济产量和生物产量提高。籽粒平均灌浆速率和最大灌浆速率提高是旱田补灌作物增产的主要机制。     

扎龙湿地对乌裕尔河流域水文特征的响应

流域的地表径流是河滨湿地的主要补给水源,对于其生态系统的演变起决定性的作用。本文对乌裕尔河流域的水文特征及其变化趋势进行了详细的分析,并阐述了这种水文特征对扎龙湿地景观、水质、生物及生态功能方面的影响,在此基础上,提出了维持湿地健康的管理对策。     

利用水系自动提取技术确定干旱区季节性干沟

为了研究极端干旱区季节性河流集水网的自动生成技术,采用ArcGIS平台提供的水文分析模型,在数字高程模型的基础上,进行戈壁集水区干沟的自动提取,讨论汇流累积阈值对提取干沟的影响,并与TM影像中的干沟进行叠加比较,检验自动提取沟谷的精度。结果表明：集水面积阈值越小,提取河网越致密,反之则提取河网稀疏。由于研究区地域辽阔,根据研究目标当集水面积阈值为4.5 km2时,提取沟谷已经较好地刻画了戈壁集水区干沟分布状况,所提取的沟谷在整个集水区上游山区以及支干主干沟道与实际沟谷吻合较好,可以满足应用需要。集水面积阈值与河源1级沟谷数相关曲线存在转折点,可以根据转折点时对应的集水面积阈值,初步确定沟谷提取的最佳阈值。     

Spatial patterns of lacustrine fish assemblages in a catchment of the Mississippi Alluvial Valley

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Characteristics of Caragana korshinskii and Hippophae rhamnoides stemflow and their significance in soil moisture enhancement in Loess Plateau, China

Stemflow of xerophytic shrubs represents a significant component of water replenishment to the soil-root system and influences water utilization of plant roots at the stand scale,especially in water-scarce semi-arid ecosystems.The stemflow of two semi-arid shrubs(Caragana korshinskii and Hippophae rhamnoides)and its effect on soil moisture enhancement were evaluated during the growing season of 2011 in the semi-arid loess region of China.The results indicated that stemflow averaged 12.3%and 8.4%of the bulk precipitation for C.korshinskii and H.rhamnoides,respectively.Individual stemflow increased in a linear function with increasing rainfall depth.The relationship between funneling ratios and rainfall suggested that there existed a rainfall depth threshold of 11 mm for both C.korshinskii and H.rhamnoides.Averaged funneling ratios were 156.6±57.1 and49.5±30.8 for C.korshinskii and H.rhamnoides,respectively,indicating that the canopy architecture of the two shrubs was an effective funnel to channel stemflow to the root area,and C.korshinskii showed a greater potential to use stemflow water in the semi-arid conditions.For individual rainfall events,the wetting front depths were approximately 2 times deeper in the rooting zone around the stems than in the bare area outside canopy for both C.korshinskii and H.rhamnoides.Correspondingly,soil water content was also significantly higher in the root area around the shrub stem than in the area outside the shrub canopy.This confirms that shrub stemflow conserved in the deep soil layers may be an available moisture source for plant growth under semi-arid conditions.     

洞庭湖流域径流量对气候变化和人类活动的响应研究

为了定量化研究气候变化和人类活动对洞庭湖流域径流量变化的影响,采用累积距平分析和Mann-Kendall趋势检验对流域内4个水文站和16个气象站1985—2010年的水文及气象数据进行统计分析,并利用径流量变化定量分析方法,计算了气候变化和人类活动对径流的改变量及其贡献率。研究结果表明:降水量的下降和潜在蒸散发量的上升导致整个洞庭湖流域及湘江、资水、沅江、澧水4个子流域突变后相对于突变前径流量分别减少了28、15、130、112 mm和102 mm;洞庭湖流域径流量的减少主要受气候变化的影响,其贡献率为64%,人类活动虽然能增加径流,但是两者的叠加影响整体上仍使径流量减少。因此,洞庭湖流域的水文干旱是自然环境演化的结果,与全球气候变化的大格局息息相关。     

Re‐introduction of structurally complex wood jams promotes channel and habitat recovery from overwidening: Implications for river conservation

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临沂市茶叶产业发展现状与对策

结合临沂市"南茶北引"发展史、茶叶产业发展现状,分析了临沂市茶叶产业发展中遇到的问题,从政策资金、科技创新、宣传推介、挖掘茶文化内涵等方面提出了发展建议,旨在以市场为导向,探索适应时代进步和社会发展要求的茶叶产业发展对策。