黑河流域中游人工水循环系统在分水前后的变化

介绍了黑河流域中游人工水文循环过程及其中各系统之间的关系,目标是为黑河流域生态—水文过程模拟提供一套较准确的数据集。利用张掖市水利年报、莺落峡水文站资料以及张掖市水资源管理年报等调查数据分析了黑河分水前后,2000年和2010年黑河流域中游引水、输水和用水系统的变化过程,得出以下结论:①人工水文循环过程通过引水系统、输水系统、储水系统和用水系统来影响农业水资源在时空上的分配,它是人类活动影响下的中游水文循环过程的重要组成部分;②2010年比2000年引水口门减少了26处,渠道综合水利用率提高了3.6%;③与2000年相比,2010年地表水和地下水资源开发利用在空间上产生了很大变化,地表水引水量减少了1.05亿m3,地下水开采量增加了1.64亿m3。最后,从径流、地下水、大气水方面分析了人工水循环过程对自然水循环过程的影响。     

Advances in the study of the Crop Evapotranspiration in Changing Environment

Significant changes in the regional energy process, water recycling and the biological process have taken place due to the climate change and human activities, and the regional agriculture has been affected by these changes. It is therefore a key issue for the regional agricultural water resource management to accurately monitor and evaluate the change of crop evapotranspiration under a changing environment. The development of the evapotranspiration theory was first reviewed, and then, the driven mechanisms and the research progress of crop evapotranspiration were illustrated. The suitability of the current monitoring method and evaluation model of the evapotranspiration in the crop evapotranspiration research under climate change were analyzed. After that, the current studies of the agricultural water resources management of “ET-based” were reviewed, and finally, the research tendency of the crop evapotranspiration on the theory, methods and application management in the future were prospected.     

玛纳斯河流域水资源利用及其存在的问题

新疆玛纳斯河流域平原区的水资源开发利用历史悠久。随着研究区工农业和社会经济的不断发展,灌溉工程体系日趋完善。总的水资源开发利用思路较为合理,对当地经济和生态环境的发展起着积极的推动作用,但也存在一些不合理的因素,导致了生态环境形势严峻、溢出带泉流量减少、地下水位持续下降和水质恶化等环境问题。据此,本文提出了水资源合理开发利用建议。     

Water security and rainwater harvesting: A conceptual framework and candidate indicators

Rainwater-harvesting tanks (reservoirs) in Tamil Nadu, India support agricultural livelihoods, mitigate water insecurity, and enable ecosystem services. However, many tanks have fallen into disrepair, as private wells have supplanted collectively managed tanks as the dominant irrigation source. Meanwhile, encroachment by peri-urban development, landless farmers, and Prosopis juliflora has reduced inflow and tank capacity. This exploratory study presents a conceptual framework and proposed indicator set for measuring water security in the context of rainwater harvesting tanks. The primary benefits of tanks and threats to their functionality are profiled as a precursor to construction of a causal network of water security. The causal network identifies the key components, causal linkages, and outcomes of water security processes, and is used to derive a suite of indicators that reflect the multiple economic and socio-ecological uses of tanks. Recommendations are provided for future research and data collection to operationalize the indicators to support planning and assessing the effectiveness of tank rehabilitation.     

Entrainment of E. coli and Listeria monocytogenes from sediment in irrigation canal

E. coli and Listeria monocytogenes (or L. monocytogenes) are bacteria affecting fresh produce that is harmful for health of humans and animals. If these bacteria are present in surface waterbody (e.g., irrigation canals), they will impair irrigation water quality and threaten produce safety. This paper studied the resuspension of E. coli and Listeria from bed sediment into irrigation water through several sets of laboratory experiments in an open channel flume. We studied three types of sediments using several flow rates in different velocities and shear stress. Bacteria's concentration in water increases with the bed shear stress. Two empirical relations were derived to correlate the concentration of E. coli and L. monocytogenes with the dimensionless bed shear stress. The experimental data favorably verified the relationships for sandy loam, loamy sand, and loam. The results showed that both bacteria could entrain from sand more efficiently compared to other sediments (i.e., sandy loam or loam). These relationships can be applied to water quality models for simulating E. coli and L. monocytogenes transport in irrigation canals for better managing irrigation water quality.     

An integrated methodology for assessing soil salinization, a pre-condition for land desertification

Soil salinization is mainly an arid-zone problem leading to land desertification. It reduces soil quality and limits the growing of crops. The control of this problem involves inventorying, mapping, and monitoring soil salinity, which requires cost-effective, rapid, and reliable methods for determining soil salinity in the field, and rapid, specific data-processing methods. This paper shows the usefulness of an integrated methodology involving a hand-held electromagnetic sensor (Geonics-EM38) and the ESAP (Electrical conductivity or salinity, Sampling, Assessment and Prediction) software for assessing, predicting, and mapping soil salinity. The salinity of a 0.45-ha surface-irrigated plot was analysed by reading the EM38 at 161 locations, and by employing the ESAP software for calibrating the sensor, and predicting and mapping soil salinity at multiple depths. To calibrate the EM38 sensor, the electrical conductivity of the saturation extract (ECe) of 57 soil samples taken at 19 points was measured. The multiple linear regression (MLR) calibration model predicted ECe from EM38 readings with R² ranging from 0.71 to 0.95 for the multiple-depth profile. Furthermore, the MLR calibration model provided field range average estimates of soil salinity. Fifty-seven percent of the field had ECe values above 4 dS m⁻¹. The salinity levels and distribution in the root zone identified areas with inverted profiles, which revealed drainage problems. The integrated method presented is a breakthrough in the ability to accurately and rapidly assess soil salinity in agricultural lands.     

内蒙古河套永济灌域渠道底泥有机质和总氮含量特征

排灌系统底泥特征是反映土地利用变化生态影响的重要途径,为此对内蒙古河套灌区永济灌域灌排系统底泥有机碳和总氮含量进行了系统研究。结果表明:灌域内永济给水干渠(简称永济干渠)与四号、五号排水干沟(简称四排干、五排干)表层底泥的有机质(OM)及总氮(TN)含量特征分布有所差异。其中均以五排干上游底泥中含量最高,OM与TN平均值分别为3.60%和0.35%,超出河套地区平均值的4.82倍和2.94倍;其底泥有机指数也达到重污染水平,富营养化程度较高;永济干渠底泥OM与TN含量最低,分别为1.41%和0.03%,属于清洁贫营养化级别;四排干底泥OM与TN含量介于五排干和永济干渠之间,其上游较为清洁,基本接近平均值,C/N平均在17左右。排干底泥有机质与总氮含量之间显著相关,y_(TN)=0.141x_(OM)-0.180(r=0.978;P<0.001)。     

作物的耐盐性及盐水灌溉管理

盐从水分关系、离子毒害、营养和能量平衡等方面影响植物的生长。不同的植物具有不同的耐盐性,同一植物在不同生长期的耐盐性也有差异。有效的灌溉管理是盐水灌溉农业的基础,高频率灌溉有利于缓解由于盐引起的水分亏缺,和对根系带洗盐,同时必须保持植物根系带土壤良好的通透条件。沙地更适合于盐水灌溉,滴灌是最为有效的灌溉方式。灌溉水盐分的增加将导致大多数作物的产量下降,但某些作物品质的改善可在一定程度上补偿产量下降的损失。     

干旱地区灌溉生产函数与经济用水灌溉定额的确定方法探讨

本文利用最优化计算方法,分析了干旱地区作物产量与灌溉定额之间的关系,论证了灌溉生产函数的求解与经济用水灌溉定额的确定方法,为灌区计划用水提供科学根据。     

甘肃秦王川灌区农业节水途径探讨

 甘肃秦王川灌区水资源紧缺,兰州新区城镇化建设加速水资源消耗趋势,使灌区水资源供需矛盾日渐突出,农业节水势在必行。根据中国西北干旱地区农业节水取得的成效和灌区农业生产节水试验,提出适宜于秦王川灌区农业节水的5条具体途径:①发展以地面灌溉为主的先进灌溉技术;②渠道衬砌;③农业节水技术与地膜覆盖栽培技术相结合;④推行膜下滴灌技术;⑤倡导节水文化,共建节水型社会。通过这些农业节水技术的实施,使秦王川灌区从简单的农业灌溉,转变为农业、城乡生活、生态、工业等多元用水格局,促进灌区经济可持续发展。