Negatively pressurized irrigation (NPI) method, a newly irrigation technology, in which the elevation of the emitters is higher than that of the water source, runs under negative hydraulic head.
负压灌溉法是一种新近提出的节水灌溉技术，灌溉时供水水头为“负值”，即灌溉水源高程低于灌水器高程。
The research results will have an important value for studying further varying-head infiltration and soil moisture characteristic of water storage pit irrigation.
这一研究成果对进一步研究蓄水坑灌条件下的变水头入渗及土壤水分运动特性具有重要价值。
The research results have an important value for further study of varying-head infiltration and soil moisture characteristic of water storage pit irrigation.
这一研究成果对蓄水坑灌条件下的变水头入渗及土壤水分运动特性的进一步研究具有重要价值。
A mathematical model whose variable is water head can simulate the effects of water head and properties of subsurface irrigation pipe on irrigation.
以压力水头为因变量的数学模型可以模拟供水压力和灌水器特性对灌溉效果的影响。
The research results will have an important value for to study further varying-head infiltration and soil moisture characteristic of water storage pit irrigation.
这一研究成果为进一步研究蓄水坑灌条件下的变水头入渗及土壤水分运动特性奠定基础。
The tubing will be primed from the pump head to the irrigation tip.
管路中从泵端到灌溉点必须必须注满水。
Water infiltration of water storage pit irrigation is under varying-head conditions.
蓄水坑灌条件下的土壤入渗是在变水头作用下进行的。
The technology of natural low-head irrigation has the advantage of water-saving and energy-saving, but its uniformity is poor for the low pressure.
自流灌区的自然低水头微灌技术，既节水又节能，但因自然水头低导致微灌系统灌溉均匀性差。
Axial flow pump with flow rate, head low, which is widely used for agricultural irrigation and urban water supply.
轴流泵具有流量大、扬程低的特点，广泛地用于农业排灌、城市供水等领域。
Some useful methods provailed in our country are presented here for calculating the economical head in pumping irrigation.
本文介绍了国内关于经济扬程现有的几种计算方法，并分别进行了分析评价。
The optimal sprinkler configuration of center-pivot irrigation system can be obtained with the model, at the same time, the demand flow and head pressure were given.
利用该方法和数学模型可确定中心支轴式喷灌机的最佳喷头配置方案，同时得出与该方案相匹配的机组入机流量和入机压力。
The different structure of the three-way pipe lead to the different local loss of head, it cause a great influence on operating costs of irrigation.
“三通”结构形式的不同会造成不同的局部水头损失，对灌溉运行费用影响很大，所以对三通结构进行优化，减小灌溉水头和局部水头损失有相当大的意义。
This scenario would also apply to the situation of using irrigation waters from a farm dam to provide power because the water level, and therefore the Gross Head, would vary enormously.
这种情况也适用于使用情况从一个农场水坝提供灌溉用水的权力，因为水位，因此，在总团长，将大相径庭。
Applies to the lower groundwater levels for high head sites, and other occasions, such as mines, high-rise buildings, water booster, mountain water for irrigation and other fruit.
适用于地下水位较低的场所及其它扬程要求高的场合，如矿井、高楼大厦、自来水增压、山区果农灌溉用水等。
Because of these low-lying areas water lift is not high but the irrigation or drainage water a considerable loser should adopt a "low-head large flow" performance characteristics of axial flow pump.
这些地区由于地势低洼，提水扬程不高，但农田灌溉或排涝的输水量相称大，应该采用“低扬程、大流量”性能特点的轴流泵。
Because of these low-lying areas water lift is not high but the irrigation or drainage water a considerable loser should adopt a "low-head large flow" performance characteristics of axial flow pump.
这些地区由于地势低洼，提水扬程不高，但农田灌溉或排涝的输水量相称大，应该采用“低扬程、大流量”性能特点的轴流泵。
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