玉米节水灌溉技术研究现状及发展趋势

节水灌溉技术可以帮助农民有效管理水资源，提高作物产量和水利用效率。以玉米为研究作物，基于玉米种植中灌溉环节存在的问题，提出玉米节水灌溉技术的必要性，系统论述了玉米节水灌溉技术研究现状，总结目前玉米节水灌溉新技术及未来发展趋势。研究结果旨在为提高玉米产量和水资源利用率提供理论参考与借鉴。     

金乡县发展节水灌溉回顾与思考

从金乡县水资源状况和节水灌溉现状出发，介绍了发展节水灌溉取得的成就，对各种节水灌溉模式作了分析。提出了目前发展节水灌溉过程中值得思考的问题及建议，可为同类地区推广节水灌溉技术提供参考。     

开封市农业节水措施研究

开封市是一个水资源严重短缺的地区，供需矛盾异常尖锐，发展节水灌溉是缓解开封市水资源短缺的唯一出路。在阐述开封市水管理状况、水资源利用现状和水资源利用趋势基础上。对开封市农业节水的必要性及其节水潜力等方面存在的问题进行分析，并提出了灌区农业灌溉节水措施。     

衡阳市节水灌溉发展模式的探讨

发展节水灌溉的目的是缓解农业灌溉水资源的紧张局面，发展节水灌溉主要是通过工程措施与非工程措施来提高水资源的利用率和水分生产率。衡阳市是湖南省的三大干旱区之一，其节水灌溉的发展模式，可供条件类似的山丘干旱地区在发展节水灌溉时参考。     

推广多途径的农业节水措施

随着全球水资源的日趋紧张，发展节水农业愈来愈重要。发展节水农业，需要推广多途径农业节水措施。我国大力发展了节水灌溉面积，推广了田间节水灌溉技术，减少作物及田间的水量损失，并逐步发展污水灌溉等。研究和推广全面的节水技术，加强水资源的管理，是促进节水工作效益显著的关键。     

高扬程灌区节水灌溉中存在的问题

水是农业的命脉，是国民经济发展的生命线，我国是一个水资源较为短缺的国家，甘肃省水资源短缺尤为严重，特别是甘肃省高扬程灌区分布较多，水资源综合利用成本较高。因此，必须大力推行节水灌溉，才能保障经济社会可持续发展。以兴电灌区为例，在分析了节水灌溉中存在的问题，提出了今后高扬程灌区发展节水灌溉应采取的对策和思路。     

推广多途径的农业节水措施

随着全球水资源的日趋紧张，发展水农业愈来愈重要，发展节水农业，需要推广多途径农业节水措施。我国大力发展了节水灌溉面积，推广了田间节水灌溉技术，减少作物及田间的水量损失，并逐步发展污水灌溉等，研究和推广全面的节水技术，加强水资源的管理，是促进节水工作效益显著的关键。     

大型灌区农业高效用水的对策

为探讨在水资源短缺和干旱条件下，大型灌区如何实现农业高效用水，提出了优化配置和联合运用灌区内的各种水资源，调整灌区的作物种植结构，采用节水灌溉制度，因地制宜选用节水灌溉技术，节水灌溉与农业综合技术相结合，改革灌区的用水管理等对策措施。     

推广水稻节水灌溉,促进农业可持续发展

由于水资源贫乏，干旱程度加重，水田面积增长，用水供需矛盾突出及节水灌溉的巨大效益，必须推广水稻节水灌溉技术。介绍了普通旱育移植和水稻超稀植栽培条件下的节水灌溉试验成果。同时，介绍了推广水稻节水工作采取的主要措施及节水灌溉的经济效益，发展前景。     

节水灌溉技术推广中的几个问题

在过去的几年中，为探索缓解水资源紧缺问题的路子，我们做了大量的节水灌溉示范推广工作，建成了一批节水灌溉示范区，全国各地尤其是西北、东北和华北地区，节水灌溉发展迅速，修建了大量的节水灌溉工程。以低压管道灌溉和喷滴灌为主的节水灌溉面积迅速增加，全国低压管道、喷灌、滴灌等各种先进节水灌溉技术推广面积已达333．33万hm2。应该说：节水灌溉技术的发展与推广，对减少农业用水的浪费，提高水的利用率，缓解用水紧张矛盾，提高作物产量等方面起到了非常重要的作用，收到了较好的社会效益与经济效益。特别是对于水资源紧缺地区，…     

Water scarcity: Fact or fiction?

It is surprisingly difficult to determine whether water is truly scarce in the physical sense at a global scale (a supply problem) or whether it is available but should be used better (a demand problem). The paper reviews water scarcity indicators and global assessments based on these indicators. The most widely used indicator, the Falkenmark indicator, is popular because it is easy to apply and understand but it does not help to explain the true nature of water scarcity. The more complex indicators are not widely applied because data are lacking to apply them and the definitions are not intuitive. Water is definitely physically scarce in densely populated arid areas, Central and West Asia, and North Africa, with projected availabilities of less than 1000 m³/capita/year. This scarcity relates to water for food production, however, and not to water for domestic purposes that are minute at this scale. In most of the rest of the world water scarcity at a national scale has as much to do with the development of the demand as the availability of the supply. Accounting for water for environmental requirements shows that abstraction of water for domestic, food and industrial uses already have a major impact on ecosystems in many parts of the world, even those not considered “water scarce”. Water will be a major constraint for agriculture in coming decades and particularly in Asia and Africa this will require major institutional adjustments. A “soft path” to address water scarcity, focusing on increasing overall water productivity, is recommended.     

沈阳地区作物需水量的预测研究

采用水量平衡法实测和模型模拟对两种作物的需水状况进行了对比研究，并对预测作物需水量的模型在本地区的有效性进行检验；目前，沈阳地区作物需水量的研究尚少，本研究对沈阳地区作物需水情况的进一步研究提供基础资料。结果表明，作物需水量的预测和实测值非常接近，相对误差和绝对误差很小，另外，对多气象因素和土壤蒸发的关系进行了拟合。得到拟用模型对沈阳地区大豆和玉米作物的需水量预测精度很高，在缺失土壤蒸发资料时，可用气象数据对其预测。     

Sensitive variables controlling salinity and water table in a bio-drainage system

Bio-drainage can be considered as an important part of sustainable irrigation water management. Bio-drainage has potential for managing shallow water conditions in arid and semiarid areas especially when traditional subsurface drains are not available. Bio-drainage theory does not go back too far. The relationship between soil characteristics, water management regimes, and climatic conditions is not yet well defined. This study attempted to use a mathematical model (SAHYSMOD) to evaluate factors affecting design and operation of a bio-drainage system and study its sensitivity to different variables. The study showed that the major constraint of bio-drainage is salt accumulation in tree plantation strips in arid and semiarid regions. Maximum soil water salinity which can be controlled by bio-drainage is around 3 dS m^?1 in rather medium run and sustainability may only be achieved where a salt removal mechanism is considered. The study also showed that the effectiveness of the system is higher where the neighboring strips are narrower. It also showed that bio-drainage is very sensitive to the amount of applied water. While the barrier depth does not have an important effect on water table draw down, it does have a great influence on lowering the salinization rate of tree plantation strips. The application of bio-drainage could be economically controversial since in humid areas water is sufficient for agricultural crops, allocating parts of the expensive land to mostly non-fruit trees may not be feasible, while in arid and semiarid regions there is usually enough cheap land to grow trees.     

Determining the disaggregated economic value of irrigation water in the Musi sub-basin in India

In this paper the residual method is used to determine the disaggregated economic value of irrigation water used in agriculture across crops, zones and seasons. This method relies on the belief that the value of a good (its price by its quantity) is equal to the summation of the quantity of each input multiplied by its average value. By applying this method to the Musi sub-basin; a subdivision of the Krishna basin in India, it was found that the value of irrigation water use is not equated across the crops, zones and seasons. The reasons why there is no sinlge value of irrigation water use are suggested. As farmers do not have perfect knowledge, do not all possess the same resource base, plant different crops for a variety of reasons (some for a financial return on land instead of water and others for sustenance), possess different crop rotation practices and are possibly riks adverse, they all value water differently. However, the results need to be interpreted with care as the crop with the lowest return to water is probably not the one to be sacrificed if water is restricted, since farmers plant crops for a variety of reasons (and sometimes not for the highest return to water that they can achieve).     

塑封保温过水即热式电磁涡流热水器设计

提出了一种塑封保温过水即热式电磁涡流热水器,电源线在绝缘容器外部,发热部件在绝缘容器内部,电源线与发热部件不接触,电源与被加热的水完全隔离,具有高效安全加热流动水的特点,推导了水加热过程中吸收热量、消耗电功率、过水流量与电磁涡流热水器热效率之间关系的计算公式,数值算例表明塑封保温过水即热式电磁涡流热水器技术上是可行的,具有较高的热效率。     

新型蓄水保墒机具的开发前景

中国水资源的时空分布很不均衡,降雨由东向西减少.西北干旱半干旱区域,年降雨总量少,且按季节分配不均,年降水的60%～70%集中分布于6-9月,降水强度大.要解决西北干旱缺水问题,可从增水、蓄水、保水、高效用水等4个方面综合考虑.就目前形势来看,西北地区水资源的补充主要靠天然降水.为此,研发一种经济、有效的蓄水保墒技术及机具对雨水资源的利用将产生重大的影响.该机具一机多用,少耕免耕,不破坏原有植被,不会引发水土流失,有良好的开发前景.     

水位-流量关系曲线在山区无量水设施渠道水量测量中的运用

贵州省灌区渠道兴建较早,渠系量水设施不配套,导致农业灌溉用水量长期以来不能准确测定。因此,探索简单易操作的农业灌溉用水量测定方法,对制定合理的水量分配制度具有重要意义。通过选取贵州省黔西县民乐灌区总干渠作为试点,采用流速仪测定该干渠不同水位下的流量,绘制水位流量关系曲线,并归纳该渠道水位流量关系经验公式,为落后山区无量水设施灌区的农业灌溉用水量探索一种简单实用的测定方法。     

农民对农业水价承受能力研究

农民是农业水价承受的主体，其承受能力的大小决定着农业水价改革的力度和进程，通过对人民胜利渠道灌区农民对农业水价承受能力的调查:揭示了灌区的运行能力是随着农业水价的上调逐步增加的，而用水是逐步减少的;农民对农业水价改革的承受能力是非常有限的;当农业水费占到农民年收入的4%一6%(支出的6%一8%)、农业投入的10%-12%和产出的8%-10%时，农民普遍认为水价合理或者基本合理，表示可以接受、愿意缴纳，说明水费没有超出农民的经济和心理承受能力;提出了促进农业水价改革的综合对策。     

Improving agricultural water productivity: Between optimism and caution

In its broadest sense, water productivity (WP) is the net return for a unit of water used. Improvement of water productivity aims at producing more food, income, better livelihoods and ecosystem services with less water. There is considerable scope for improving water productivity of crop, livestock and fisheries at field through to basin scale. Practices used to achieve this include water harvesting, supplemental irrigation, deficit irrigation, precision irrigation techniques and soil-water conservation practices. Practices not directly related to water management impact water productivity because of interactive effects such as those derived from improvements in soil fertility, pest and disease control, crop selection or access to better markets.However, there are several reasons to be cautious about the scope and ease of achieving water productivity gains. Crop water productivity is already quite high in highly productive regions, and gains in yield (per unit of land area) do not necessarily translate into gains in water productivity. Reuse of water that takes place within an irrigated area or a basin can compensate for the perceived losses at the field-scale in terms of water quantity, though the water quality is likely to be affected. While crop breeding has played an important role in increasing water productivity in the past, especially by improving the harvest index, such large gains are not easily foreseen in the future. More importantly, enabling conditions for farmers and water managers are not in place to enhance water productivity. Improving water productivity will thus require an understanding of the biophysical as well as the socioeconomic environments crossing scales between field, farm and basin.Priority areas where substantive increases in water productivity are possible include: (i) areas where poverty is high and water productivity is low, (ii) areas of physical water scarcity where competition for water is high, (iii) areas with little water resources development where high returns from a little extra water use can make a big difference, and (iv) areas of water-driven ecosystem degradation, such as falling groundwater tables, and river desiccation. However, achieving these gains will be challenging at least, and will require strategies that consider complex biophysical and socioeconomic factors.     

生物慢滤技术在宜昌农村饮水安全

生物慢滤技术适用于农村小型分散式饮水处理技术。通过五峰、秭归等地的实践，阐述了生物慢滤工艺的技术特点及净水原理，指出慢滤是一种不用任何机械动力和化学药剂的水处理方法。通过生物慢滤技术，水质满足饮用水要求，与同等规模的水处理设施比较，投资节省达90%，施工方便。慢滤池结构简单，运行管理方便，自耗水量少，出水水质好，在农村饮水工程中具有广泛的应用前景。