The Total Coverage Irrigation Method

Author: Menachem Cohen, Chief design engineer , NaanDanJain

This article presents a new sprinkler irrigation method for total coverage of the area. You may ask what can be new about this irrigation method, which is known around the world and is used to irrigate many crops. The new method combines the advantages of the conventional irrigation method (wetting the entire area) with the advantages of low volume irrigation (precipitation rates that are adapted to the rate that water is absorbed by the soil). This irrigation method serves a variety of crops, such as sugar beet, potatoes and leaf vegetables. The new method combines the advantages of the conventional irrigation method (wetting the entire area) with the advantages of low volume irrigation (precipitation rates that are adapted to the rate that water is absorbed by the soil). This irrigation method serves a variety of crops, such as sugar beet, potatoes and leaf vegetables.



Ornamental nursery in Mexico with Mamkad mounted on IrriStand Conifer nursery in Holland with Mamkad mounted on IrriStand
Ornamental nursery in Mexico with
Mamkad mounted on IrriStand
Conifer nursery in Holland with
Mamkad mounted on IrriStand


System structure

1. A system of three impulse sprinklers of different sizes with a plastic hammer and one or two nozzles (NaanDanJain’s 5022-U and Super Mamkad sprinklers).

2. The sprinklers are connected to 25-50 mm diameter PE laterals. Low density PE laterals, which enable flexible laying out and winding up of the laterals without tearing, have special importance.

3. Male and female bayonets in the sprinkler and PE laterals enable quick connection under operating pressure of up to 5 kg.

4. Other system components: Water supply line and manifold, operation valves, pressure regulators, head control and more – as required by every pressure irrigation system.

If the water is dirty (sand, organic matter), filters must be used to ensure the proper operation of the sprinklers, without the need to clean the nozzles during the irrigation cycle.

 

Principles of the method

1. Focus on the creation of an irrigation regimen that will create optimum soil-water-air ratio and nutrition.

The possibility of irrigation with a wide pressure range (2.0 to 5.0 kg), with a variety of nozzles and different sprinkler spacing, enables precise planning of the precipitation rate required according to the soil types, surface slope, required irrigation interval and required operating hours.

The low precipitation rate, which in many cases is close to the precipitation rate received with a dripline system, enables the absorption of the water by the soil without quick compacting of clay soil, loss of water, air compression from the soil. It enables the creation of a balance between air and water in the capillary spaces and prevention of upper drainage in sloped areas.

2. Achievement of a high irrigation efficiency.

In conventional irrigation, the accepted values for irrigation efficiency are about 80%. The ratio between the volume of water that reaches the root zone and the volume of irrigation water is always influenced by the distribution uniformity of sprinkler irrigation, loss of water in the accessories, wind, etc.

In this Total Coverage system, where the precipitation rates are relatively low, the distribution uniformity of the sprinklers is particularly high. The scheduling factor (Sc) of around 1 to 1.5 provides high irrigation efficiency of about 90%. A high irrigation efficiency ensures efficient use of water according to the crop requirements – an important factor especially in arid regions.

3. A combination of fertilization and irrigation

Creation of a fertigation system, one of the factors for increasing the quality and quantity of the yields in the low volume irrigation system, is also possible with this sprinkler system. Since most of the system’s components are made of plastic, in addition to the other aforementioned factors, combining the fertilizer with the irrigation is an especially important factor. Fertilization through the irrigation system also serves as a maintenance operation. For example, injection of phosphoric acid as phosphoric fertilizer also removes sediments of carbonates and increases the pH in the water.

Article tags: low volume irrigation, leaf vegetables, potatoes