Pulse drip irrigation is an experimental

irrigation Irrigation (also referred to as watering) is the practice of applying controlled amounts of water to land to help grow crops, landscape plants, and lawns. Irrigation has been a key aspect of agriculture for over 5,000 years and has been dev ...

technique primarily used with

drip irrigation Drip irrigation or trickle irrigation is a type of micro-irrigation system that has the potential to save water and nutrients by allowing water to drip slowly to the roots of plants, either from above the soil surface or buried below the surface. ...

. Maintaining a high level of

soil Soil, also commonly referred to as earth or dirt, is a mixture of organic matter, minerals, gases, liquids, and organisms that together support life. Some scientific definitions distinguish ''dirt'' from ''soil'' by restricting the former ...

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 A timer is a specialized type of clock used for measuring specific time intervals. Timers can be categorized into two main types. The word "timer" is usually reserved for devices that counts down from a specified time interval, while devices th ...

to reduce the watering duration and increase the watering frequency. 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. 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. Some literature also cite the benefits of small frequent watering applications to reduce

water stress Water scarcity (closely related to water stress or water crisis) is the lack of fresh water resources to meet the standard water demand. There are two types of water scarcity: physical or economic water scarcity. Physical water scarcity is whe ...

on plants. 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 Groundwater recharge or deep drainage or deep percolation is a hydrologic process, where water moves downward from surface water to groundwater. Recharge is the primary method through which water enters an aquifer. This process usually occurs ...

or runoff.

Mineral nutrients In the context of nutrition, a mineral is a chemical element required as an essential nutrient by organisms to perform functions necessary for life. However, the four major structural elements in the human body by weight (oxygen, hydrogen, carbon, ...

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 Aeroponics is the process of growing plants in the air or mist environment without soil or an Construction aggregate, aggregate medium. The word "aeroponic" is derived from the Greek language, Greek meanings of ''aer'' ("air") and ''ponos'' ("la ...

. 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, which consequently does not bind very well to water. This increases the plant's

water-use efficiency Water-use efficiency (WUE) refers to the ratio of water used in plant metabolism to water lost by the plant through transpiration. Two types of water-use efficiency are referred to most frequently: *photosynthetic water-use efficiency (also ...

. Sand is also less hospitable to pathogens that can attack roots.

Advantages

Pulse drip irrigation has the following advantages: *Less run off on heavy soils. *Less

leaching Leaching is the loss or extraction of certain materials from a carrier into a liquid (usually, but not always a solvent). and may refer to: *Leaching (agriculture), the loss of water-soluble plant nutrients from the soil; or applying a small amoun ...

or water loss in sandy soils. *Water can be applied more efficiently on shallow soils and in hilly areas. *Intermittent operation of sprinklers and foggers can provide

evaporative cooling An evaporative cooler (also known as evaporative air conditioner, swamp cooler, swamp box, desert cooler and wet air cooler) is a device that cools air through the evaporation of water. Evaporative cooling differs from other air conditioning s ...

for temperature control. *Size of growing containers in greenhouses may be reduced due to very low discharge rates. *Low flow inputs may reduce supply system costs because smaller pipes and lower capacity pumps would be needed.

Disadvantages

* The additional expense of buying and maintaining a pulse drip system to a pre-existing irrigation system. * The system requires a minimum of water pressure to run efficiently. * Maintaining the integrity of a pressurized water supply is of critical importance. Leaks in the piping can run up substantial costs due to the long duration of the watering periods. * Close attention to the watering cycles is needed to avoid salt build up in the soil. Light watering can leave salt residues behind as the water evaporates and leave little added moisture to the soil. * The additional expense of leak prevention devices (LPDs) or check valves are recommended to be fitted at each watering distribution point along the system to ensure even distribution of water. If the lines are allowed to drain between pulses, most of the water will preferentially flow to those at the beginning of the line.

References

{{reflist Irrigation Low-flow irrigation systems

Advantages

Disadvantages

See also

References