灌区实时灌溉供水模型研究

研究了灌溉系统供水计算模型.将灌区内作物概化为水稻和旱作物两种,分别以水量平衡原理和土壤水分模拟理论为基础建立稻田和旱作物灌溉供水计算模型.模型中所需要的参数如水文气象、土壤和作物参数均可通过分析历史资料或实测得到.模型系统可进行实时计算操作,并可预测下次灌溉方案,并在取得实测资料后对原预报方案进行实时修正,从而编制实时灌溉方案.模型还可研究灌溉系统内各子系统的优化供水流量和优化轮灌方案.     

新疆平原区井渠结合地下水数值模拟与分析

为了减少引用地表水量,充分利用地下水以实现节水的目标,针对新疆克孜河下游平原区伽师县新垦 58 团盐碱化严重的现象,采用井渠结合的灌溉排水模式.利用 Modflow 对确定典型区的地表水、地下水联合调度进行模拟,并对区内水源地开发规模进行模拟预测,得到区内合理的地下水开采规模,实现地下水控制到临界深度,减少土壤返盐,减少潜水无效蒸发,提高用水效率.     

河南省节水灌溉及其对策研究

在河南省节水农业技术研究项目的实践基础上,系统阐述了河南省节水灌溉的重要意义、现状和存在问题,并在综合分析研究全省的气候、地形地貌和土壤条件之后,结合水资源、经营规模、管理能力和经济社会发展状况,把全省划分成若干个节水灌溉的类型区,同时分别提出节水灌溉和调整农业结构的措施和对策.     

塔里木河南岸14团灌区地下水资源评价与分析

本文运用水均衡法和开采系数法,依据水均衡原理建立14团灌区内地下水水均衡模式,对灌区的地下水资源进行评价和分析,目的是科学合理开发利用地下水,保持水土平衡,促进灌区经济可持续发展.     

旱作物灌溉用水预测公式

从土壤湿润层水量平衡出发,推导出旱作物灌溉用水预测公式,利用历史实测灌溉用水及同期降雨资料率定有关参数,根据降雨预报资料预测灌溉用水量。方法简便,适用于种植结构不明的灌区,特别是数个灌区构成的灌溉区域。     

膜孔灌溉点源入渗模型的建立与验证

膜孔灌溉的田面人渗属于充分供水条件下的点源三维人渗问题。根据对点源人渗所做的系统室内试验研究,建立了包含有膜孔直径、土壤质地及土壤初始含水量等多因子的点源人渗模型,经检验模型具有一定的拟合精度,从而为膜孔灌溉理论与灌水技术要素的深入研究奠定了基础。     

覆膜旱作水稻作物系数试验研究

分析了覆膜旱作水稻需水量试验资料,得出覆膜旱作水稻各生育阶段综合作物系数。综合考虑了覆膜旱作技术对水稻生理生态的影响,提出了涵盖水稻冠层叶面积指数、天顶角绿叶覆盖串、含遮阴地表植被有效覆盖串及移栽后天数等稻株生长影响因素等综合作物系数计算公式。计算结果与实测值较吻合,经F检验具有极显着性水平,可以用于覆膜旱作水稻实际蒸发蒸腾量的计算。     

灌溉水库水资源综合利用的多目标决策模型

以湖南龙源水库为例,应用系统分析方法,建立了以灌溉为主综合利用水库优化续建规划和调度运用的大系统多目标决策模型,并提出用带有变动惩罚项的动态规划法求解多目标动态规划模型.实例研究表明:数学模型和求解方法是可行的,优化调度所取得的效益是显著的.     

Estimation of Columbia River virgin flow: 1879 to 1928

The Columbia River is a major source of and conduit for Pacific Northwest economic activity, and is one of the more heavily modified rivers in North America. Understanding human and climate‐induced changes in its hydrologic properties is, therefore, vital. Long streamflow records are essential to determining how runoff has changed over time, and Columbia River daily streamflow record at The Dalles began in 1878. To understand and separate anthropogenic and climate effects, however, it is also necessary to have a basin‐scale estimate of virgin or naturalized flow. The United States Geological Survey has calculated a monthly averaged adjusted river flow at The Dalles for 1879–1999 that accounts for the effects of flow regulation. The Bonneville Power Administration has estimated the monthly averaged virgin flow at The Dalles, i.e. the flow in the absence of both flow regulation and irrigation depletion for 1929–89. We have estimated the monthly virgin flow of the Columbia River at The Dalles from records of irrigated area for the missing early years, i.e. for the period 1879–1928. In addition, to allow hindcasting of a virgin flow sediment transport for the system, a daily virgin flow index with realistic higher moments and spectral properties has been calculated. Examination of the virgin flow record shows that climate change since the late 19th century has decreased annual average flow volume by > 7%; irrigation depletion has reduced the flow by another ∼7%. Copyright © 2005 John Wiley & Sons, Ltd.     

Responses of canopy transpiration and canopy conductance of peach (Prunus persica) trees to alternate partial root zone drip irrigation

We investigated canopy transpiration and canopy conductance of peach trees under three irrigation patterns: fixed 1/2 partial root zone drip irrigation (FPRDI), alternate 1/2 partial root zone drip irrigation (APRDI) and full root zone drip irrigation (FDI). Canopy transpiration was measured using heat pulse sensors, and canopy conductance was calculated using the Jarvis model and the inversion of the Penman–Monteith equation. Results showed that the transpiration rate and canopy conductance in FPRDI and APRDI were smaller than those in FDI. More significantly, the total irrigation amount was greatly reduced, by 34·7% and 39·6%, respectively for APRDI and FPRDI in the PRDI (partial root zone drip irrigation) treatment period. The daily transpiration was linearly related to the reference evapotranspiration in the three treatments, but daily transpiration of FDI is more than that of APRDI and FPRDI under the same evaporation demand, suggesting a restriction of transpiration water loss in the APRDI and FPRDI trees. FDI needed a higher soil water content to carry the same amount of transpiration as the APRDI and FPRDI trees, suggesting the hydraulic conductance of roots of APRDI and FPRDI trees was enhanced, and the roots had a greater water uptake than in FDI when the average soil water content in the root zone was the same. By a comparison between the transpiration rates predicted by the Penman–Monteith equation and the measured canopy transpiration rates for 60 days during the experimental period, an excellent correlation along the 1:1 line was found for all the treatments (R² > 0·80), proving the reliability of the methodology. Copyright © 2005 John Wiley & Sons, Ltd.