灌区节水灌溉用水量的计算

灌区灌溉用水量的计算,过去多是采用水量平衡方法,即根据土壤水分平衡原理,计算出作物需水量,进而推算出高产条件下的灌溉制度,然后根据作物组成和灌溉面积计算出总用水量。这种计算方法没有考虑经济问题。本文利用农业生产投入与产出的关系,用极值法确定合理节水用水的灌溉定额,由此计算出产值最大时的灌溉用水量,即经济效益最大时的灌溉用水量。     

傍河井取水与引黄河水之间的关系分析

以莘县为例,探讨傍河井抽取的地下水与引黄河水之间存在的关系。研究结果表明,引黄沟渠在抽水井影响半径2倍以外时,傍河井的数量或者抽水量足以引起引黄沟渠周围区域性地下水位下降,则引黄河水对该区域的地下水补给量就会增加,取水量越大,地下水位下降越大,补给量增加的也越多;当引黄沟渠在抽水影响半径2倍之内时,引黄河水就会直接补给水井,补给量与水井的单位时间出水量、水井与引黄沟渠的距离、抽水时间有关,出水量越大、距离越近、抽水时间越长,引黄河水的侧渗补给量越大,反之依然。     

井灌工程优化规划方法的研究

以平原灌区旱、涝、碱综合治理为前提,以控制地下水位等为约束条件,进行灌溉水资源供需平衡计算;用供需平衡计算确定的最大开采量作为各种布井方案的标准,计算各种布井方案的投资、运行管理费用和能耗;进行各种井灌工程方案的优选。     

井灌工程优化规划方法的研究

以平原灌区旱,涝,碱综合治理为前提,以控制地下水位等为约束条件,进行灌溉水资源供需平衡计算;用供需平衡计算确定的最大开采量作为各种布井方案的标准,计算各种布井方案的投资,运行管理费用和能耗;进行各种井灌工程方案的优选。     

河北省栾城县地下水数值模拟

为了研究现阶段条件下河北省栾城县的地下水资源状况，在数值模拟的基础上，对地下水资源量进行了评价，同时，预测了农业节水20%、30%，以及工业使用南水北调客水条件下，栾城县地下水位的动态变化趋势。数值模拟表明，地下水超采是造成地下水位持续下降的主要原因，若农业灌溉节水20%～30%，则对防止地下水位的持续下降具有明显的效果。     

灌区引黄水和地下水联合运用的最优规划

开封市农业灌溉用水主要由引黄水和当地地下水供给,针对灌区多年年份的供水条件,在地下水削减的不同情况下,提出在全灌区地面水和地下水联合运用最优分配和最优用水量的问题.在提出的这一问题中,通过采用变量的一维搜索技术,并将非线性函数用分段线性函数来近似,将建立的被控对象的数学模型的非线性规划问题转化为线性规划问题.通过单纯性法计算,选择不同的决策变量和不同的参数,逐步逼近不同的供选方案,求得近似最优解.对研究开封农业水资源承载力分析有参考价值.     

水资源评价新途径商榷

<正> 通常在利用地面水灌溉的规划设计中,都是按照灌溉面积、灌水次数和灌水定额的乘积,除以渠系水的利用系数,计算灌区灌溉用水量,在开发利用地下水灌溉规划设计中、常根据地下水的补给量(降水和地面水的入渗补给、地下径流的侧向补给、不同含水层间的越流补给,以及灌溉回归水的补给等)计算地下水的可开采量,然后与灌区需要的水量对比,说明地下水资源的盈亏。     

Web下节水灌溉远程监控系统——评《节水灌溉规划》

我国水资源人均占有量仅为全球人均水量的25%左右,是世界贫水大国。在水资源消耗中,农业用水量约为总用水量的90%左右。在开展大棚种植及大规模的农田种植中,传统需要进行人工灌溉,以确保农业种植的产量。现如今,农业灌溉系统采用多个传感器分布节点进行水量控制,实现多点灌溉。为减少灌溉用水量,达成节水灌溉,要求开展节水灌溉的远程监控系统设计,依托监控系统对灌溉点出水量进行监测,并开展智能调节,进而确保灌溉效率。     

渭-库河三角洲绿洲农作物需水量分析

对渭一库河三角洲绿洲的主要农作物需水量为研究对象,采用FAO-PM公式,主要农作物不同灌溉方式的需水量进行计算及统计分析。结果显示:主要农作物的传统灌溉总用水量为44.66亿m3,节水灌溉定额总需水量只有为11亿m3,传统灌溉总用水量比节水灌溉定额总需水量大约4.06倍多(33.03亿m3),导致农业用水浪费严重;在渭-库河三角洲绿洲大部分农田仍然采用粗放的大水漫灌和宽河大渠输水的灌溉方式为主,因此,通过采用滴灌、膜上滴灌、膜下滴灌和喷灌等高效节水灌溉技术,可以增加节约水量,并达到农业节水灌溉的目的,这表明可挖节水灌溉潜力相当大。研究对渭一库河三角洲绿洲水资可持续利用提供经验和技术保障,并提出高效节水灌溉的新思路、新方法、新举措,为渭-库河绿洲发展高效节水灌溉农业提供科学依据。     

邯郸市地下水压采效果简析

邯郸市地处河北省最南部,属极度资源性缺水地区。各种用水量中,农业用水量在所有行业中所占比例最大,特别是邯郸东北部平原地区,由于水资源严重匮乏,不得不依靠大量超采深层地下水来维系,所以要开展地下水超采综合治理,大力推广节水灌溉技术。本文以邯郸市地下水压采项目为基础,分析在此节水灌溉水平下,所能达到的节水量与存在的问题,为今后有关部门的决策部署提供参考。     

Overland water and salt flows in a set of rice paddies

Cultivation of paddy rice in semiarid areas of the world faces problems related to water scarcity. This paper aims at characterizing water use in a set of paddies located in the central Ebro basin of Spain using experimentation and computer simulation. A commercial field with six interconnected paddies, with a total area of 5.31 ha, was instrumented to measure discharge and water quality at the inflow and at the runoff outlet. The soil was classified as a Typic Calcixerept, and was characterized by a mild salinity (2.5 dS m⁻¹) and an infiltration rate of 5.8 mm day⁻¹. The evolution of flow depth at all paddies was recorded. Data from the 2002 rice-growing season was elaborated using a mass balance approach to estimate the infiltration rate and the evolution of discharge between paddies. Seasonal crop evapotranspiration, estimated with the surface renewal method, was 731 mm (5.1 mm day⁻¹), very similar to that of other summer cereals grown in the area, like corn. The irrigation input was 1874 mm, deep percolation was 830 mm and surface runoff was 372 mm. Irrigation efficiency was estimated as 41%. The quality of surface runoff water was slightly degraded due to evapoconcentration and to the contact with the soil. During the period 2001–2003, the electrical conductivity of surface runoff water was 54% higher than that of irrigation water. However, the runoff water was suitable for irrigation. A mechanistic mass balance model of inter-paddy water flow permitted to conclude that improvements in irrigation efficiency cannot be easily obtained in the experimental conditions. Since deep percolation losses more than double surface runoff losses, a reduction in irrigation discharge would not have much room for efficiency improvement. Simulations also showed that rice irrigation performance was not negatively affected by the fluctuating inflow hydrograph. These hydrographs are typical of turnouts located at the tail end of tertiary irrigation ditches. In fact, these are the sites where rice has been historically cultivated in the study area, since local soils are often saline-sodic and can only grow paddy rice taking advantage of the low salinity of the irrigation water. The low infiltration rate characteristic of these saline-sodic soils (an experimental value of 3.2 mm day⁻¹ was obtained) combined with a reduced irrigation discharge resulted in a simulated irrigation efficiency of 60%. Paddy rice irrigation efficiency can attain reasonable values in the local saline-sodic soils, where the infiltration rate is clearly smaller than the average daily rice evapotranspiration.     

瓦房店市水果生产标准化发展研究

瓦房店市是我国重要的水果生产基地,在国内水果生产领域占有重要地位。随着水果市场化的不断深入,如何满足和适应国内外市场需求成为瓦房店市水果生产的关键问题。从瓦房店市水果生产实际出发,阐述了实施水果生产标准化的必要性,提出了发展水果生产标准化的具体措施。     

金谷子耐旱TG118引种试种及推广应用

对引进的谷子新品种金谷子耐旱TG118进行品种比较试验和多点试种。结果表明：该品种抗旱、耐瘠、适应性强,稳产、高产、抗病抗风抗倒伏强,品质优良,粮草兼用,种植简单,省工易管;一般产量在6000kg/hm2以上,比当地主栽品种增产20%以上。最高产量达9450kg/hm2,适于在辽西北地区推广应用。     

对《种子法》存在问题的探讨

《种子法》是我国种植业第一部法律。自实施以来,为依法加强种子管理提供了有力的法律支撑,促进我国种子产业发生翻天覆地的变化。但随着依法管理工作的深入和种子产业的快速发展,《种子法》及配套规章的一些问题逐步显现出来。对《种子法》及配套规章存在的问题进行深入分析,对需要进一步补充的章节以及需要调整的内容进行深入探讨,以求更加完善和明确。     

Review of the Egyptian experience in implementing land drainage projects

About 30 years have passed since the Government of Egypt embarked on implementing a series of large scale drainage projects. At present, about 3.8 million acres have been provided with drainage systems on the basis of systematic pre-drainage investigations and designs. The target is to provide drains in approximately 6.4 million acres in the Nile Valley and Delta.The implementation of the subsurface drainage system is carried out by the public sector and private contractors under direct supervision of governmental regional departments. The implementation process depends on many factors related to the drainage material, machinery, manpower, site requirements, farmers and organizations involved. Problems and constraints are sometimes challenging, however, the annual rate of implementation has gradually increased to 170,000 acre/year.This paper discusses the different aspects involved in the implementation process of drainage systems. The development in materials, machinery and construction technologies will be reviewed. Institutional and management factors are going to be also considered.     

和谐社会理论建设的几点哲学思考

在新世纪,面对机遇和挑战,党的十六大把“社会更加和谐”作为全面建设更高水平的小康社会的一个重要目标。中国人素有社会和谐的理想;西方人自古也向往社会和谐;借鉴东西方两种和谐社会思想的经验、教训,构建社会主义和谐社会理论。     

A European irrigation map for spatially distributed agricultural modelling

We present a pan-European irrigation map based on regional European statistics, a European land use map and a global irrigation map. The map provides spatial information on the distribution of irrigated areas per crop type which allows determining irrigated areas at the level of spatial modelling units. The map is a requirement for a European scale assessment of the impacts of irrigated agriculture on water resources based on spatially distributed modelling of crop growth and water balance. The irrigation map was compiled in a two step procedure. First, irrigated areas were distributed to potentially irrigated crops at a regional level (European statistical regions NUTS3), combining Farm Structure Survey (FSS) data on irrigated area, crop-specific irrigated area for crops whenever available, and total crop area. Second, crop-specific irrigated area was distributed within each statistical region based on the crop distribution given in our land use map. A global map of irrigated areas with a 5′ resolution was used to further constrain the distribution within each NUTS3 based on the density of irrigated areas. The constrained distribution of irrigated areas as taken from statistics to a high resolution dataset enables us to estimate irrigated areas for various spatial entities, including administrative, natural and artificial units, providing a reasonable input scenario for large-scale distributed modelling applications. The dataset bridges a gap between global datasets and detailed regional data on the distribution of irrigated areas and provides information for various assessments and modelling applications.     

粉质仪和拉伸仪在面粉生产中的应用

在介绍粉质仪和拉伸仪结构和原理的基础上,探讨了粉质曲线中吸水率、形成时间、稳定时间、弱化度和评价值等指标与面粉品质的关系,以及如何根据拉伸曲线中面团最大拉伸阻力、延伸度和拉伸曲线面积等指标来评价面团品质,并结合生产实际,概述了粉质仪和拉伸仪在面粉生产中的作用。     

农村信息化服务的现状及建设措施

分析当前我国农村信息化服务的现状,提出加强农村信息化服务的新举措。     

车辆ABS控制算法的研究及探讨

对现代汽车的ABS控制算法作了一些简单的介绍,同时指出了它们的一些缺陷,相应地提出了几种对ABS的其它控制方法并加以探讨,其中着重论述了ABS门限值控制算法中参考车速的确定方法和基于附着系数的控制算法。