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。

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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。

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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。

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But a low-head dam that delivered irrigation water also blocked fish movement.

CNN: Migrating fish get help in uphill battle