Methods of Irrigation and Efficiency
A basin of shallow depth (about 10 cm) is prepared around the base of the palm, and the basins of adjacent palms are interconnected with furrows. Water is allowed to flow freely from the furrows to the basin.
This method is not suitable for undulating lands. Even in flat lands, considerable land preparation is required initially to allow free flow of water.
The water requirement for this method is high as considerable amount of water is lost due to soil absorption, leaching, and evaporation. This method is particularly not suitable for sandy soils due to heavy losses of water by percolation. Furthermore, it is difficult to apply a fixed volume of water to a palm by this method. Initial cost is Rs 9500-11000 per acre.
This method is useful to protect seedlings in the dry and dry intermediate zones where mortality rate is high. Following are the steps in the pitcher irrigation
- Take two unglazed clay pots having capacity of 15-20 liters and make a hole at the bottom of each pot and insert a 2feets long rope.
- Paint one side of the pot so that water will not seep through.
- Bury the clay pot up to the neck at 0.7 m distance to the plant with painted surface away from the plant placing the rope in the direction of the plant.
- Fill the pot with water, keep the mouth of the pot closed and top up regularly. Generally, during the dry weather, it may necessary to fill it in twice a week.
Although the water is used efficiently in this method, the rate of water flow to the plant is very slow. Therefore, the method is not very suitable for adult palms. Cost is Rs 250 per plant
An underground PVC pipes network to supply water to outlets is more suitable for coconut plantation. One inch diameter and 100 ft long rubber hoses are used to irrigate 16 palms within the one outlet. This would facilitate other practices in the estate such as weeding, picking and transport of nuts. Also it facilitates to irrigate intercrops and maintenance is very easy and profitable. The pipe system consist main line sub main line and risers. At the end of each riser, 1”ball valves are installed to deliver water to palms.
The hose irrigation system could be done at a cost of Rs: 20000-25000 per acre.
Drip irrigation system is feasible in coconut lands. Drip irrigation involves the wetting of a smaller soil volume in the root zone to provide the water requirement of plant. Advantages of this system are as follows.
- It requires relatively less water as the system can be designed for efficient use of water. The water usage can be regulated.
- Fertilizer could be added to the irrigation water, thereby saving cost of fertilizer application.
- Intercrops also could be irrigated with simple modification to the system.
The high capital investment and maintenance problems are the disadvantages of this system. Installation cost is Rs 30000-45000 per acre.
Pipe network and other accessories are similar to the drip irrigation. But perorated poly ethylene tube ring is used around the base of the palm in order to dippers. Less maintenance problems compare with the drip irrigation. Installation cost is similar to Drip irrigation.
Spray jet Irrigation
Pipe system and other accessories are similar to the drip irrigation. Small sprayers are used to irrigate the root zone of coconut in order to drippers. Advantages of this method are as follows: