词条 | Pulse drip irrigation |
释义 |
Pulse drip irrigation is an experimental irrigation technique primarily used with drip irrigation. Maintaining a high level of soil moisture for germination of seed is one reason this technique may be used. Most conventional drip irrigation systems can be made to pulse by using a timer to reduce the watering duration and increase the watering frequency.[1] Some newer systems have been developed that utilize a pressurized reservoir. When the pressure in the reservoir reaches some predetermined pressure level the valve on the reservoir opens and a portion of the fluid contained within the reservoir is forcefully discharged. While the fluid is discharging, the pressure within the reservoir decreases. When the decrease in water pressure reaches a predetermined level the valve closes to resume the charging phase. The charge-discharge cycling will continue as long as the flow rate coming in through the inlet is less than the expel rate passing out through the outlets while the valve is open. A device called a drip flow controller is placed at the inlet for this purpose to regulate the flow into the inlet.{{cn|date=July 2017}} If properly designed and operated, a low-flow pulse system may be left operating continuously for a period of time without overwatering. Constant and frequent irrigation applications have been cited as one way to reduce water demand.{{cn|date=July 2017}} Some literature also cite the benefits of small frequent watering applications to reduce water stress on plants.[2][3] Low-flow application rates can be used with different soils and growth media. The water can be applied slowly enough to match the water infiltration rate and prevent water loss from deep percolation or runoff. Mineral nutrients added to media with a high void content, such as coarse grained sand, will provide more oxygen to roots than ordinary soil and share some of the advantages with aeroponics. Sand also has a low water retention potential that makes it easier for plants to extract water by expending less energy due to the sand's relatively large particle size,{{cn|date=July 2017}} which consequently does not bind very well to water. This increases the plant's water-use efficiency{{cn|date=July 2017}}. Sand is also less hospitable to pathogens that can attack roots.{{cn|date=July 2017}} AdvantagesPulse drip irrigation has the following advantages:
Disadvantages
See also
References1. ^{{cite web|url=http://cedb.asce.org/cgi/WWWdisplay.cgi?21784 |title=Basic Principles of Pulse Irrigation |publisher=Cedb.asce.org |date=2010-01-09 |accessdate=2013-11-26}} 2. ^{{cite web|title=EFFECT OF PULSE DRIP IRRIGATION ON SOIL MOISTURE DISTRIBUTION AND MAIZE PRODUCTION IN CLAY SOIL|url=https://www.academia.edu/1418565/EFFECT_OF_PULSE_DRIP_IRRIGATION_ON_SOIL_MOISTURE_DISTRIBUTION_AND_MAIZE..}} 3. ^{{cite web|title=The Effect of Discharge Rate and Intermittent Water Application by Point-source Irrigation on the Soil Moisture Distribution Pattern|url=https://dl.sciencesocieties.org/publications/sssaj/abstracts/43/1/SS0430010008}} 2 : Irrigation|Low-flow irrigation systems |
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