提高绿水生产效率之探析

绿水是一种通过土壤蒸发和植被蒸腾等流向大气圈的水汽蒸散流.中国的绿水资源量为3.4万亿m3,占降水资源总量的54%.现综述了绿水在陆地生态系统中的作用及影响绿水流因素,结合国外相关研究进展,给出了提高绿水生产效率的几种途径,为进一步开发利用绿水资源提供参考.     

水稻无水层灌溉水分生产率分析

通过较长时间小区试验,对水稻3种灌溉方法的产量、用水量、水分生产率进行了研究。结果表明:无水层灌溉与薄露灌溉、习惯灌溉相比,早稻分别增产651,990 kg/hm2,增产率为10.3%、16.5%;晚稻分别增产717,1 175 kg/hm2,增产率为9.9%、17.4%。同时,灌溉水量早稻分别节水830,3 150 m3/hm2,节水率为46%、69%;晚稻分别节水1 410,2 955 m3/hm2,节水率为58%、74%。无水层灌溉早稻、晚稻水分生产率分别为2.67,2.94 kg/m3,达到了国际领先水平。     

Sorghum Water Loss in Relation to Irrigation Treatment

Aiming towards rational irrigation water management in a seasonally dry climate, sorghum water losses via evapotranspiration were studied during a two-year experiment in relation to irrigation treatments in Central Greece. Relative to high irrigation (IH), that provided the root depth with 458 mm of water in 1994 and 512 mm in 1995, 56 and 64% of the water was supplied by the medium (IM) and 34 and 46% by the low (IL) treatments, respectively, during the two years. A fourth treatment (IHA) was performed like (IH) until the end of anthesis, when irrigation stopped. Gravimetric soil moisture was measured, biometric measurements were taken and all meteorological parameters required to estimate evapotranspiration by the Penman–Monteith equation were logged. A model estimating sorghum actual water loss was first run with the 1994 data. During the model-establishment year, it was found that (a) surface resistance rs, consisting of a canopy rsc and a soil rss resistance acting in parallel, was almost exclusively dependent on soil water shortage, (b) under the IM and IL irrigation treatments, the lowest possible (immediately after water application) canopy resistance r'sc, higher than the (IH) minimum canopy resistance rsc (min) = 40 sm-1, was irrigation-deficit dependent and (c) the rss (min) was as high as 1200 sm-1, common to all treatments. The model established was then verified with the 1995 data and used to calculate the crop coefficient kc values for sorghum. The model, although tending to underestimate actual evapotranspiration by 4–10%, depending on the treatment, may be considered as reliable. The kc values calculated are considerably higher than the kc values suggested for sorghum by the Food and Agriculture Organization (FAO). Therefore, taking also into account that any additional mm of water supplied results in an increase of 0.052 t of dry biomass per hectare, higher irrigation water applications could be recommended, although the low irrigation treatment made slightly better use of water.     

Water and the CGIAR: A Strategic Framework

Abstract

Among the many institutions addressing development issues at the international level, the 16 research centers of the Consultative Group of International Agricultural Research (CGIAR) focus on the goal of reducing poverty, hunger, and malnutrition by sustainably increasing productivity of resources in agriculture, forestry, and fisheries. The CGIAR has certain comparative advantages in carrying work in water at the various scales, from the farm up to global, that should be offered to the international community. This discussion paper addresses the question: what are the major water issues relevant to the CGIAR goal? The paper also presents a justification of the research needs and opportunities as well as some initial ideas for the development of a specific research agenda on each area. While other international organizations are very active in many international initiatives, the CGIAR is one of the few that could contribute much needed research information in many world areas. The CGIAR must focus more on water in relation to the plight of the poor in particular. There is a need to increase the adaptive capacity of the poor, and to manage the water supply and quality constraints. This could be achieved by focusing at the community level and by developing inexpensive, easy to use monitoring tools that would alert the communities of forthcoming problems and provide them with means to take remedial action. This action is often needed long before there is any hope of changes in policy and other macro-level interventions. The fundamental issue of water as a food requires that attention be given to the quantity and quality of water available for domestic use in poor households and communities. Health issues associated with domestic supply and with irrigation management have been important research themes in the CGIAR and demand increasing attention. Given the current composition, activitiesm and comparative advantages of the CGIAR, it is proposed that research on water management should focus on the following four broad general areas: (1) improving the efficiency of water use in agriculture through increased water productivity; (2) management of watersheds for multiple functions; (3) management of aquatic ecosystems, in particular those sharing boundaries with terrestrial ecosystems; and (4) policy and institutional aspects of water management. As the aim of water management research is to address water constraints and issues in an integrated manner, the four areas cannot be treated in isolation from each other. There is thus a need for the fifth area for achieving integration at and across different scales.     

Water Productivity in Irrigation Systems

Abstract

Situated in the south of the Iberian Peninsula, the Guadalquivir river basin's irrigation systems suffer from frequent water shortage due to the shortfall in this basin's average hydrological balance. Viable solutions are non-existent in the Spanish hydrological planning framework, neither in the Guadalquivir river basin nor in what the National Hydrological Plan (Ministerio de Medio Ambiente, 2001) has to offer. Therefore, it is necessary to turn to economic tools in order to find solutions, which will affect the demand or the reallocation of resources. In this study, a method that calculates the water productivity of an irrigation system and compares the result with the water cost paid by farmers is proposed and put into practice. The economic viability of resource reallocation and the application of the cost recovery principle can be studied using this data and can help with the more efficient use of water resources.     

Transjurisdictional Water Pollution Management in China: The Legal and Institutional Framework

The current study shows that the recent diesel price hike had an insignificant impact on irrigation costs incurred by diesel well owners in eastern India. Further, analysis of the farming enterprises of diesel well owners and water buyers from both diesel and electric wells confronted with a differential cost of irrigation water showed that farmers would be able to cope with a very high rise in irrigation costs through irrigation efficiency improvements and allocating more area to crops that give higher returns per unit of land and water. By doing this, they are able to maintain the farm returns.     

现代灌溉水管理发展理念及改善策略研究综述

对现代灌溉水管理发展理念和改善策略的研究进展与趋势进行综述,探讨了有关的研究重点与内容.现有成果表明,研究探索诸如考虑农田排水或灌溉回归水再利用的灌溉效率、灌溉经济社会净收益极大化的经济效率以及灌溉用水尺度的水分生产率等灌溉水管理发展理念及其改善策略,对加强灌溉水管理、提高农业用水效率、确保食物安全、减少环境负效应、增加农业产出效益具有十分重要的意义和作用.鉴于灌溉效率、经济效率、水分生产率等指标具有明显的尺度效应,应在研究建立相应于各评价指标的尺度化特定表达式基础上,探索不同尺度特定表达式间可能存在的定量转换关系,实现相同评价指标下的尺度数量转换,为评价灌溉用水尺度效用、采用适宜于不同用水尺度的灌溉水管理策略提供科学的分析手段与定量方法.     

浅析ET与农作物产品虚拟水之间的关系

首先引入ET和虚拟水及水分生产率的概念,详细介绍目前ET和虚拟水及水分生产率的计算方法,并对ET与农产品虚拟水的相互联系进行重点探讨,同时就目前国际上较为先进的ET技术和虚拟水战略理论的概要进行解释,提出了农业结构战略性的调整和区域水资源管理的有效措施和建议。     

灌溉定额与灌溉水矿化度对春玉米水分利用效率影响研究

通过在甘肃省石羊河流域开展春玉米咸水灌溉田间试验,研究了灌溉定额和灌溉水矿化度对春玉米耗水量及水分利用效率的影响.研究结果表明:春玉米耗水量随着灌溉定额的增大而增大,随着灌溉水矿化度的增大而减小.而从充分利用土壤贮水的角度考虑,非充分灌溉能够提高土壤播前贮水的利用量,而咸水灌溉则会降低土壤贮水利用量;非充分灌溉有利于提高春玉米的水分利用效率和灌溉水分利用效率,而咸水灌溉会降低春玉米的水分利用效率和灌溉水分利用效率.本次试验得到淡水轻度缺水灌溉处理的水分利用效率和灌溉水分利用效率最大值分别为2.90 kg/m~3和4.23 kg/m~3.与淡水充分灌溉处理相比,在研究区若采用灌溉定额为340 mm和灌溉水矿化度为0.71 g/L的灌溉方式,春玉米的水分利用效率和灌溉水分利用效率可提高25%以上,同时可节水170 mm.     

Water footprints and irrigated agricultural sustainability: the case of Chile

This paper estimates the agricultural production water footprint (WF) of Chile, assessing green, blue and grey WFs of the main agricultural products for the main productive regions, taking into account climatic and soil differences. Chile’s agricultural production blue WF is geographically concentrated in the lower portion of the Northern Dry Pacific and Central Chile area, which present less water availability. Thus, irrigated agricultural production in Chile, a semiarid country, is characterized by high water stress. In this scenario, public policies are required to incentivize better water management in order to reduce water vulnerability while boosting development.     

不同水势对干制辣椒产量和水分利用效率的影响研究

试验主要研究在西北干旱地区膜下滴灌条件下,不同水势处理对干制辣椒产量和水分利用效率的影响,从而确定适合该地区的辣椒滴灌控水下限。试验根据滴头下25cm深处土壤的基质势设置5个控水下限：-10kPa、-20kPa、-30kPa、-40kPa和-50kPa,测量的指标主要有叶面积、株高、土壤水分和产量等。试验结果表明,以-30kPa为灌水下限的处理具有较高的叶面积指数、株高、最高的辣椒产量和水分利用效率。而控水下限过高和过低均会影响产量。因此在西北干旱地区膜下滴灌条件下,建议干制辣椒的控水下限为-30kPa。     

温室盆栽黄瓜耗水量与水分利用效率的试验研究

试验研究表明，从黄瓜移入温室盆内到拉秧，在生育期内，每盆单株黄瓜总耗水量为１１～１９．６ｋｇ，平均耗水１４．９ｋｇ，日耗水量４．３～８．３ｍｍ。每株黄瓜产量０．４～１．３ｋｇ，水分利用效率３８～６６ｇ／ｋｇ株，即每生产１ｋｇ黄瓜需水量１５～２６ｋｇ。经过８３ｄ生育期的灌水，土地盐分的累积十分迅速，土壤盐分平均增加１．１３～１．６７倍，因此必须注意盐分的控制。     

川中丘陵区节水栽培技术对冬小麦水分利用效率的影响

水分不足是限制川中丘陵区冬小麦生长发育及产量的重要因子。通过不同节水栽培措施条件下耗水特性、潜在蒸散量与作物系数的研究成果,对冬小麦的产量与水分利用效率进行了分析。试验结果表明：①在冬小麦全生育期,常规灌溉（保证田间持水量75%）耗水量最高,达到421mm ;依赖于降雨耗水量最低,仅为348mm 。②川中丘陵区冬小麦生育期逐日的潜在蒸散量（ET₀）的平均值在0.93～3.81mm/d 幅度内变动,并呈现出前期平稳、中后期逐渐增加的特征。③在冬小麦全生育期,各处理措施的K_c值幅0.23～1.92之间,并呈现一抛物线特征。在拔节期达到最大值,成熟期达到最低值;且秸秆覆盖+常规灌溉栽培措施平均K_c值最大,对照平均K_c值最小。④冬小麦产量以秸秆覆盖+常规灌溉处理最高,达到 6 222.53 kg/hm²,而以对照（A）最低,仅为3 852.00kg/hm²;冬小麦的水分生产率与灌水生产率则均表现为秸秆覆盖+节水灌溉处理最高,分别达到0.55kg/m³和3.62kg/m³。     

基于生产函数的中国水资源利用效率探讨

通过扩展的省级生产函数计算边际单位水资源价值,构造相关生产函数来描述我国大陆各省、市(自治区)的经济活动。利用2000—2005年的经济数据以及水资源数据,从生产力角度分析各地区的水资源利用状况。分析结果表明,我国大陆各省、市(自治区)以边际水资源利用价值为表征的水资源使用效率在研究期限内都有所提高,北方等缺水地区无论从空间还是从时间段来看,水资源利用效率及其改进幅度都显著地高于南方地区。在此基础上提出了有关政策建议。     

Drivers of change in agricultural water productivity and its improvement at basin scale in developing economies

We approach the issue of water productivity in agriculture by identifying five sets of drivers of change. We find that irrigation efficiencies at the field level can result in real water savings under certain conditions, but that small farmers in most of South Asia and Africa have little incentive to adopt the appropriate measures. Although water productivity improvement and water savings at the regional level are possible through a shift to economically efficient crops, such changes may be constrained by concerns with respect to domestic and regional food security, rural employment, and farming system resilience.     

Moving beyond ‘more crop per drop’: insights from two decades of research on agricultural water productivity

ABSTRACT

Concern over increasing water scarcity has led to the introduction of the concept of agricultural water productivity and an emphasis on interventions to achieve ‘more crop per drop’. Yet, a strong debate continues on how the concept is to be defined and used. Drawing largely from the irrigation literature, the origins of the concept and its methodological developments are reviewed, and its use in applied work over two decades is discussed. Based on this analysis of conceptual and applied research, key insights into the concept’s contributions and limitations are presented, as well as opportunities for further refinements.     

水库水权的稳定性与水权效率探析

通过对水库水权不稳定的效率损失分析,总结出水库水权边界模糊,产权份额分配不清,受自然因素影响,水权收益不稳定4个方面因素导致水权不稳定。研究表明,水权界定明晰,用水者水权稳定,是提高水权效率的重要前提,并提出稳定水库水权的相关政策建议。     

水账户方法及其在流域水分生产率分析中的应用

引入水账户理论和方法,以研究流域水资源的利用状况。介绍了水账户的概念体系、基本数学表述、尺度和平衡要素。该方法根据水平衡原理,对流域内不同用途的水进行分类。通过分析水资源在生态经济系统中的流向、流量和存量等的变化过程,完整地呈现研究区内的所有用户,以便分析提高可用水量的途径及节水的可能性。应用该方法对黑河流域中游张掖市水资源利用情况的分析表明,研究时间内田间尺度所有可用水均被损耗殆尽,导致土壤水储量减少,减少水分的无效损耗量是提高灌区水资源利用率的重要措施。从流域尺度上看总入境水量中92.6%被损耗利用,该市的水资源利用处于不可持续的极限状态。最后讨论了不同尺度水分生产率转化、农业节水措施选择、流域生态健康与水利用效率的关系等,指出仅提高渠系利用率和渠道衬砌率等措施不能从根本上提高水分生产率,水利用效率的提高应以全流域水利用效率为指标。     

冬小麦生理过程调控高效用水研究

文中探讨在水资源严重短缺情况下，如何充分利用冬小麦生理过程的用水调控作用,达到节水、高效。     

Water Productivity in a Rigid Irrigation Delivery System

The rotational irrigation water delivery (warabandi) system practiced in the Indus river basin of Pakistan has continued for 100 years. Irrigation water allocated to the farmers under the warabandi system is proportional to farm size and is fixed. This rigid allocation system has been partly justified by its contribution to social equity though this may have been at the cost of economic gains. In order to assess the operation of warabandi’s basic rules, a farmers’ survey was completed from 124 farmers located on five watercourses. A questionnaire was administered to each farmer and farm management data were gathered. As fresh water resources are under stress and becoming scarce their efficient use in all applications should be assured in water allocations. It is shown from the survey results that water allocation based on very limited criteria does not maximize the socio-economic benefits gained from the use of scarce water. Thus, it is suggested that the existence or non-existence of fresh groundwater resources along with other critical variables should be taken into consideration when making canal water allocation decisions. Missed water deliveries due to failure of the canal system appear to be the largest cause of losses. Water charges need to be increased to fund large improvements in canal maintenance programs. It is pointed out that a framework should be developed as a tool to improve water productivity for Pakistan. This should include: consideration of the gross area of a tertiary canal, sensitivity of crop growth stage to water shortage, crop value, bias of allocation towards most water use efficient areas and water use efficient crops, the potential losses from water deficiency.