A postscript: Macroeconomics and structural adjustment — the minimum for water sector specialists

The need for a grasp of macroeconomic concepts and methods for microeconomists and technical specialists is stressed. At this juncture policy failure is commonplace. Experience in using the World Bank Structural Adjustment in Lowinca as a training exercise is discussed.     

Water management for irrigation in Antiquity (Urartu 850 to 600 B.C.)

The kingdom of Urartu existed in Eastern Anatolia from about 850 B.C. to 600 B.C. Historical references and archaeological evidence indicate the considerable artistic and technical skill of the Urartian people. The supply of the kingdoms capital Tupa/Rusahinili with drinking and irrigation water is an outstanding example of a well-planned and excellently built historical inter-basin water management project. The system has been in operation for more than 2000 years and still serves, at least partly, its original purpose.     

Modernization of furrow irrigation in the South-East of France automation at field level and its implications

Surface irrigation rehabilitation in the South-East of France has shown success ever since the beginning of its development in the early 1980s. The gradual introduction of surface distributors, mechanized or automated has resulted in water savings and above all in decreased labor input. The distributors used are: gated pipes, layflat tubing, buried low pressure pipe and cablegation. They are used over an ever increasing area which attained about 1000 ha in 1987.Improvement is made in furrow head distribution as well as in field levelling, furrow flow evaluation, flow control at the head of the furrow and in the collective system.The effect of a modernized system and improved knowledge has been to make automated surface irrigation (particularly furrow irrigation) a modern application method in competition with techniques such as sprinklers and localized irrigation.Abbreviations ASAE American Society of Agricultural Engineers - CEMAGREF Centre d'Etude du Machinisme Agricole du Génie Rural des Eaux et des Forêts, Division Irrigation, BP 5095, 34033 Montpellier et BP 31 Le Tholonet 13612 AIX - ENGREF Ecole Nationale du Génie Rural des Eaux et des Forêts, Département Maîtrise de l'Eau et Développement, BP 5093, 34033 Montpellier - IRAT Institute de Recherche en Agronomie Tropicale, Zolad Mini Parc Bt7, 34100 Montpellier - P.V.C. Polyvinyl chloride - RNEDHA Réseau National Expérimentation Démonstration secteur Hydraulique Agricole, BP 5095, 34033 Montpellier - SCP Société du Canal de Provence et d'Aménagement de la Région Provençale, BP 100, 13603 AIX en Provence     

A comparative description of two farmer-managed irrigation systems in Nepal

The organization of two farmer-managed irrigation systems in the western hills of Nepal is described by examining the ways in which the activities of water allocation, water distribution, maintenance, and resource mobilization are performed. Due to the topography and environment, these two organizations are structured primarily to mobilize the large amount of labor required for maintenance of the intake and canal. Both organizations precisely define each member's water allocation. In one system, water is allocated in proportion to the area of an individual's land holding, while in the other water allocation is by purchased shares. These two cases were used to analyze the importance of the principle of water allocation for expansion of area irrigated and equity of access to irrigation. Evidence from the two systems shows that in this hill environment water allocation by purchased shares provides the individual incentive and an organizational mechanism for efficient development of irrigation resources. Expansion of area irrigated and equity of access to irrigation were found to be greater in the system which allocates water by purchased shares than where water was allocated in proportion to area irrigated.     

喷灌工程规划设计多方案选优的语言化与定量化相结合模糊综合评判数学模型

本文提出了喷灌工程规划设计多方案选优的语言化与定量化相结合的模糊综合评判数学模型,从而可得到比传统喷灌工程规划设计方案选优方法更为合理、满意的结果。     

保雨灌溉技术的研究与推广

保雨灌溉技术的核心是向天空要水,与蒸发夺水,充分利用自然降水和土壤水分,满足作物需要。在作物需水不足时,提取地下水补充灌溉。三年试验结果表明,保雨灌溉比常规井灌年均节水2091mm/hm~2,增产粮食2020kg/hm~2,促进了优质高效农业的发展。     

Farmers' irrigation practices in a high rainfall area

Recent droughts in the humid southeastern United States have focused attention on the need for and use of supplemental irrigation. Total annual rainfall amounts are sufficient for most crops in the region. However, erratic distribution of rainfall and the low water-holding capacities of most soils in the region cause frequent drought stresses in many crops. An on-farm study was conducted in southeastern Alabama to evaluate the effects of farmers' irrigation scheduling decisions on soil moisture variations in peanut fields irrigated with center-pivot irrigation systems. The study showed that the way irrigation was practiced in this high rainfall area often caused soil moisture deficit (SMD) level higher than the desired SMD limit during over 20% of the 140-day growing season. This is partially due to farmers' tendency to delay irrigation in anticipation of rainfall which may or may not occur, as rainfall during the growing season is often erratic and local. In contrast SMD in non-irrigated fields was higher than the SMD limit for half of the growing season.Abbreviations SMD soil moisture deficit - ET evapotranspiration - R_eff effective rainfall - WHC water holding capacity     

棉花调亏灌溉的生态生理效应

在人工控制试验条件下 ,采用子母盆栽土培法 ,以棉花为试验材料进行了调亏灌溉试验研究。结果表明 ,棉花调亏灌溉是可行的 ,可以实现节水、高产和高效的目标。适时适度的水分调亏显著抑制蒸腾速率 ,而光合速率下降不明显 ,复水后光合速率又具有超补偿效应 ,光合产物具有超补偿积累 ,且有利于向棉铃运转与分配 ;抑制营养生长 ,促进生殖生长。棉花调亏灌溉的适宜指标是 :苗期轻、中度调亏 ,0～ 40 cm土层湿度控制下限为田间持水量的6 0 %或 5 0 %;蕾期轻度调亏 ,0～ 40 cm土层湿度控制下限为 6 0 %;花铃期不宜调亏 ,应保证充足供水 ,0～ 40 cm土层湿度应不低于 75 %;吐絮期可中度调亏 ,0～ 40 cm土层湿度可控制在 5 0 %～ 5 5 %。     

河套灌区灌溉制度研究

根据河套灌区的气象、土壤、灌水等资料,利用ISAREG模型模拟了4种主要作物充分灌溉和非充分灌溉2种灌溉制度方案。根据模型的优化模拟结果分析,在作物产量比率仅略有下降的情况下,作物实施非充分灌溉将减少灌水次数和灌溉定额(平均下降45 mm),建议灌区把作物实施非充分灌溉作为一种节水措施之一。     

地下滴灌棉花栽培试验与技术研究

根据新疆兵团农五师九十团8hm^2地下滴灌棉花栽培、灌溉和施肥等方面的试验研究，地下滴灌与地面滴灌比较，无论投入产出和作物的长势，地下滴灌都比地面滴灌优越。地下滴灌比地面滴灌工程设备、材料费低0．15297万元／hm^2，降低年运行费用841．8元／hm^2。