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Rain Water Harvesting

Rainwater harvesting and moisture conservation in coconut lands

Water is an essential component for the vegetative growth and nut production of coconut palm. In areas with long spell of dry weather or scanty and ill-distributed rainfall, coconut production is reduced. So conservation of water in coconut growing area is important to ensure availability of water throughout the year. Generally an adult palm requires 600-800 litres of water once in four to seven days, depending on soil type and climatic condition.
This is primarily because nutrients in the soil are absorbed by root only if these are dissolved. Consequently insufficient moisture in the soil reduces palms capability to absorb nutrients, there by resulting in poor growth in young palms and low nut production.
Research shows that clay and organic matters hold the water in the soil and higher content of organic matter in the soil increases the moisture holding capacity. As much of the organic matter is present in the topsoil, so if soil erosion is checked soil continues to retain water holding capacity. It is seen that bare soils in coconut lands result in heavy erosion due to runoff. Continuous soil erosion finally results in barren land where coconut cultivation is no longer profitable. Therefore measures have to be adopted in coconut growing land to maximize the volume of rainwater to be absorbed into the soil sub layers without allowing it to run-off the land. When the rainwater collection and movement is properly managed on a land with the adoption of following measures the productivity of the land can be increased effectively.
1. Establishment of cover crops.
2. Burial of coconut husks in pits
3. Mulching on the manure circle
4. Deep planting of seedlings
5. Contour drains and bunds
6. Construction of water reservoirs along water streams in coconut estates
7. Addition of organic and green manure.
Download the technical brief written by P A Henry NimalAppuhamy, Head/Technology Transfer Division, CRISL, Lunuwila, Sri Lanka.
Some best practices to irrigate coconut lands:
• Irrigate in basins of 1.8m radius and 10-20 cm depth.
• In coastal sandy soils, sea water can be used for irrigating adult palms. But do not irrigate seedlings and very young palms upto 2 year with sea water.
• In irrigated gardens interruption of irrigation leads to serious set-back in yield and general condition of palms. Hence, when once started irrigation should be continued regularly and systematically.
• Drip irrigation is the best suited method of irrigation for coconut. It saves water, labour and energy.
(Source: Coconut Development Board, Kochi, India)

Tags: Rainwater Harvesting
 

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