Pulse drip irrigation

Illustration of a pulse drip irrigation system.[1] Magnets hold the valve closed while water comes in through the inlet and drip flow controller[2] to charge the reservoir. When the building pressure finally overcomes the attractive force of the magnets the top set of magnets are forced upward to open the valve. As the water is released the pressure decreases to a point where the magnets drop back down and the charging phase begins anew.
One of two pulsing impact sprinkler at The Crescent Grange in Broomfield, Colorado providing 5000 sq. ft. of coverage of their Permaculture garden. The sprinklers were run continuously delivering 5 second pulses per minute for the first twelve days to germinate the seeds. Thereafter it was gradually cut back to 8- to 10-hour watering periods three times a week.
Landscaping in sand with in situ seed germination. A one gallon per hour drip flow controller feeding an eighty-two foot drip line with check valves[3] comprising eighty-two drip points along its length so each drip point is putting out about 1/82 gallons per hour.
Crimson clover sprouts grown on 1/8" urethane foam mats and flagstone. Four micro-sprinklers cycle pulsing continuously over a 7 day period, each putting out about 1/2 gallon per hour. The four micro-sprinklers were each fitted with an LPD to keep the lines fully charged between pulses.

Pulse drip irrigation is a scalable low-flow irrigation technique that allows for close management of water usage and can be employed with either drip or sprinkler irrigation devices and extend conventional low-flow irrigation systems to ultra-low micro-irrigation levels.[4] Pulse irrigation is common in locations such as Israel where water conservation is a priority.

Pulse drip irrigation systems operate by passively letting water flow into a reservoir at a controlled rate to steadily build pressure within the pressurized reservoir.[5] 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.

Low-flow pulse systems can be left operating continuously without overwatering. Constant and frequent irrigation applications have been cited as one way to reduce water demand.[6][7] Some literature also cite the benefits of small frequent watering applications to reduce water stress on plants.[8][9]

Low-flow application rates can grow in different mediums. The water can be applied slowly enough to match the water assimilation rate and prevent water loss from percolation or run-off. Mineral nutrients added to mediums 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,[10] which consequently does not bind very well to water. This increases the plant's water-use efficiency. Sand is also inhospitable to pathogens that can attack roots.

Advantages

Pulse drip irrigation has many advantages for drip and sprinkler systems:

Disadvantages

References

This article is issued from Wikipedia - version of the Monday, April 25, 2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.