灌区经济灌溉面积分析

<正> 在发展灌溉的地区,水资源不足已成为制约因素。利用外调补充的地上水源发展灌溉,既昂贵而又十分有限,这就要求改革现行的灌溉制度和采取节流措施,限制灌溉次数,扩大灌溉面积、取得大面积粮食均衡增产,提高灌区的总体经济效益。 本文从水资源经济利用观点出发,应用“边际原理”,提出了以作物经济用水量为依据的、确定灌区最优规模的新方法。     

基于径向基函数神经网络右江灌区有效灌溉面积的预测

根据人工神经网络的理论和方法,建立径向基函数神经网络模型,以右江灌区的统计数据为例预测该灌区的有效灌溉面积,结果表明模型有较强非线性处理能力和逼近能力,具有学习时间短,预测精度高,适应性强等优点。     

石津灌区灌溉面积萎缩及对策研究

石津灌区建于20世纪50年代，是河北省最大的自流灌区。近年来，灌区灌溉面积逐渐萎缩，在对灌区内因和外因两方面影响因素进行分析的基础上，提出了改善工程条件、对水资源进行统一管理、发展节水灌溉、加快基层用水管理体制改革、提高职工素质等具体对策。     

Logistic方程灰色建模预测辽宁省有效灌溉面积

应用灰色系统理论,对Logistic方程参数进行灰色估计,建立Logistic方程灰色预测模型,并对辽宁省有效灌溉面积进行了模拟和预测,模拟结果与原始资料吻合很好,相关性达到0.95。辽宁省有效灌溉面积预测模型显示:有效灌溉面积的上限是158.8万hm2,2018年预测值为158.3万hm2,已经非常接近界限值,有效灌溉面积的发展不大,进行农业资源的结构调整非常必要。     

曲靖灌区新增灌溉面积0.7万公顷

云南曲靖灌区以加强水利基础设施建设和改善生态环境为根本 ,注重经济发展、生态保护和水利资源开发利用的相互协调 ,实现了水利资源的优化配置 ,变工程水利为资源水利。灌区自 1997年以来 ,共新增灌溉面积 0 .7万ｈｍ2 ,年增产粮食5 6 6 9万ｋｇ。曲靖灌区位于珠江干流南盘江上游 ,是西南地区继都江堰之后的第二大灌区 ,是目前云南省的第一大灌区。灌区的续建配套与节水改造给灌区老百姓带来了巨大的经济效益、社会效益和生态效益。首先是农民再也不用白天黑夜地去“抢水”了 ,争水吵斗的现象消失了 ,安定团结加强了。二是干渠续建配套与节…     

对大中型灌区扩大灌溉面积的思考

大中型灌区是国家的基础设施,在防洪、灌溉、供水等方面为国民经济和社会发展提供了安全保障和水资源保障,发挥了巨大的社会效益和经济效益.然而,随着农村改革的逐步深入和市场经济的冲击,大中型灌区自20世纪80年代以来灌溉面积大幅下降,以山西省滹沱河灌区为例,其主要原因有河源来水减少、渠首调蓄能力不足、地下水开发无序、粮价持续偏低、基层水利管理不力、建设用地挤占等.为了确保灌溉面积,应采取有效利用河源来水、实行水资源的统管统调、大力发展"两高一优"农业、强化基层水利组织建设、推广节水灌溉新技术等对策.     

全国大型灌区灌溉用水有效利用系数空间变异性分析

根据2006—2009年全国大型灌区样点灌区灌溉用水有效利用系数测算分析结果,采用地质统计学方法,对大型灌区灌溉用水有效利用系数空间变异性进行分析。结果表明,在650km左右范围内,大型灌区灌溉用水有效利用系数具有自相关性,结构性因素起主要作用,各向异性不明显。     

我国有效灌溉面积影响因素的灰色关联分析

定性、定量分析了我国有效灌溉面积的影响因素,并采用灰色关联分析法确定各指标对有效灌溉面积的影响。结果表明,以灰色综合关联度作为标准,5个主要影响因素依次为灌溉工程及设备、灾害影响、耕地面积、资金投入、灌溉用水量,其灰色综合关联度分别为0.577、0.546、0.538、0.534、0.525。     

确定干旱缺水灌区作物灌溉面积的线性规划模型

提要在Jensen提出的作物产量模型的基础上,考虑作物前一个生育期的灌水状况对本次灌水的影响,以及充分利用天然降雨,以灌区最大净收益为目标,建立了寻求各次灌水不同类型土壤和灌水定额的灌溉面积的线性规划模型.最后,给出了模型运行的一个实例.     

Evaluation of irrigation systems in the irrigated area of Chanza (Huelva)

In the irrigated area of Chanza (Huelva, Spain) there are about 1500 ha of strawberries under localized irrigation. A survey, covering 12% the farms and 20% of the area, was performed in order to characterize the farms, their water use, the cultivation techniques and crop yields and the localized irrigation systems used. Results of this survey were employed to select 20 farms for the evaluation of the irrigation systems using the procedure of Merriam and Keller (1978) modified according to local conditions. Results of the survey and evaluations of the strawberry crops are presented and the unitary water use determined. The conclusions summarize the main problems detected as well as their causes and possible solutions.     

太阳能应用于节水灌溉发展现状与发展趋势

近些年来,太阳能作为一种新能源在农业中得到利用,基于太阳能的灌溉技术在世界各地迅速发展起来,尤其是基于太阳能供能的节水灌溉技术更是受到较大关注。高效、节能、低碳与环保是开展现代农业的前提与基础,是开展节水灌溉与太阳能技术相互结合的保证。围绕着国内外太阳能节水灌溉技术的发展现状等研究情况进行了阐述,指出了现有太阳能节水灌溉系统的特点,并在此基础上指出了我国发展太阳能节水灌溉的必要性,开发研制相应的人工智能—太阳能自动节水灌溉系统装置,并在实践中得到较好的应用是现阶段的主要研究方向。     

黑龙江垦区灌溉工程发展建议

从垦区水资源特点、开发利用现状出发，针对垦区发展灌溉工程存在的主要问题，提出了垦区发展灌溉工程的建议。     

泾惠渠灌区作物需水量特征及影响因素分析

通过CROPWAT模型分析泾惠渠灌区冬小麦和玉米蒸发蒸腾量及灌溉需水量的变化,同时运用SPSS软件,计算灌区作物需水量与气象因子的相关系数,分析结果表明:冬小麦整个生育期蒸发蒸腾量平均值为634.04 mm,蒸发蒸腾量最高峰出现在4月中旬—5月中旬,灌区各分区蒸发蒸腾量趋势基本一致;玉米蒸发蒸腾量平均值为525.22 mm,蒸发蒸腾量高峰期出现在7月中旬—8月下旬,其中三原最大为535.97 mm,富平最小为514.68 mm;灌区冬小麦在播种—越冬期灌溉需水量最低,返青—拔节期需水量增加;灌区玉米在拔节—抽雄期需水量增加,灌溉平均需水量为133.04 mm;7月—8月为籽粒形成乳熟期,需水量为359.15 mm,至9月下旬,玉米灌溉需水量下降;灌区作物需水量与气温呈正相关,与降水呈负相关,与风速和相对湿度相关性较小,气温、日照时数和相对湿度是影响作物需水量的主要因素.     

机电一体化技术的现状和发展趋势

机电一体化是现代科学技术发展的必然结果,文章简述了机电一体化技术的基本概要和发展背景,综述了国内外机电一体化技术的现状,分析了机电一体化技术的发展趋势。     

插秧机的现状及发展趋势

作为农业生产的一部分,插秧机经历了很多个阶段,一直在随着时代的进步而改变着,因为只有适应时代发展的工具对人们来讲才是有用的,才不会被淘汰.文章通过对插秧机的现状的描述,分析其发展趋势,对其以后的研发方向进行了展望,供有关人士参考查阅.     

关于现代数控技术的发展趋势的分析

文章通过对实际情况及现代数控技术发展特点阐述,分析现代化数控技术的发展趋势的技术特点及发展方向。旨在通过分析数控技术发展趋势,对现代化数控技术又好又快发展做出一点贡献。     

Analysis of uniformity of sprinkle irrigation in a semi-arid area

One of the most appropriate sprinkler systems for arid or semi-arid areas – where a great deal of irrigating water is required – are the permanent set systems and the continuous-move laterals. To know the reality of water application in this type of areas, many field evaluations of solid set systems and centre pivot irrigation were conducted in Castilla-La Mancha region (Spain). The main factors affecting water application and evaporation and drift losses with these systems (pressure, wind speed, sprinkler type, etc.) were analysed. A set of performance guidelines and recommendations for the design and management of sprinkle irrigation is presented to attain the highest uniformity and efficiency in water application in semi-arid areas. To use working pressure as low as possible, but with sprinklers that produce a great deal of middle size water drops along with night irrigation for minimising evaporation and drift losses are important aspects.     

Expansion of urban area and wastewater irrigated rice area in Hyderabad,India

The goal of this study was to investigate land use changes in urban and peri-urban Hyderabad and their influence on wastewater irrigated rice using Landsat ETM + data and spectral matching techniques. The main source of irrigation water is the Musi River, which collects a large volume of wastewater and stormwater while running through the city. From 1989 to 2002, the wastewater irrigated area along the Musi River increased from 5,213 to 8,939 ha with concurrent expansion of the city boundaries from 22,690 to 42,813 ha and also decreased barren lands and range lands from 86,899 to 66,616 ha. Opportunistic shifts in land use, especially related to wastewater irrigated agriculture, were seen as a response to the demand for fresh vegetables and easy access to markets, exploited mainly by migrant populations. While wastewater irrigated agriculture contributes to income security of marginal groups, it also supplements the food basket of many city dwellers. Landsat ETM + data and advanced methods such as spectral matching techniques are ideal for quantifying urban expansion and associated land use changes, and are useful for urban planners and decision makers alike.     

Water use and lint yield response of drip irrigated cotton to the length of irrigation season

A 2-year experiment was conducted at Tal Amara Research Station in the Bekaa Valley of Lebanon to determine water use and lint yield response to the length of irrigation season of drip irrigated cotton (Gossypium hirsutum L.). Crop evapotranspiration (ET_crop) and reference evapotranspiration (ET_rye-grass) were directly measured at weekly basis during the 2001 growing period using crop and rye-grass drainage lysimeters. Crop coefficients (K_c) in the different growth stages were calculated as ET_crop/ET_rye-grass. Then, the calculated K_c values were used in the 2002 growing period to estimate evapotranspiration of cotton using the FAO method by multiplying the calculated K_c values by ET_rye-grass measured in 2002. The length of irrigation season was determined by terminating irrigation permanently at first open boll (S1), at early boll loading (S2), and at mid boll loading (S3). The three treatments were compared to a well-watered control (C) throughout the growing period. Lint yield was defined as a function of components including plant height at harvest, number of bolls per plant, and percentage of opened bolls per plant.Lysimeter-measured crop evapotranspiration (ET_crop) totaled 642 mm in 2001 for a total growing period of 134 days, while when estimated with the FAO method in 2002 it averaged 669 mm for a total growing period of 141 days from sowing to mature bolls. Average K_c values varied from 0.58 at initial growth stages (sowing to squaring), to 1.10 at mid growth stages (first bloom to first open boll), and 0.83 at late growth stages (early boll loading to mature bolls).Results showed that cotton lint yields were reduced as irrigation amounts increased. Average across years, the S1 treatment produced the highest yield of 639 kg ha⁻¹ from total irrigations of 549 mm, compared to the S2 and S3 treatments, which yielded 577 and 547 kg ha⁻¹ from total irrigations of 633 and 692 mm, respectively, while the control resulted in 457 kg ha⁻¹ of lint yield from 738 mm of irrigation water. Water use efficiency (WUE) was found to be higher in S1 treatment and averaged 1.3 kg ha⁻¹ mm⁻¹, followed by S2 (1.1 kg ha⁻¹ mm⁻¹), and S3 (1.0 kg ha⁻¹ mm⁻¹), while in the control WUE was 0.80 kg ha⁻¹ mm⁻¹. Lint yield was negatively correlated with plant height and the number of bolls per plant and positively correlated with the percentage of opened bolls. This study suggests that terminating irrigation at first open boll stage has been found to provide the highest cotton yield with maximum WUE under the semi-arid conditions of the Bekaa Valley of Lebanon.