REDUCING THE USAGE OF POTABLE WATER FOR HOME GARDENING BY WATER CONSERVATION TECHNIQUES IN DRY ZONE AREAS OF SRI LANKA
COVID-19 pandemic brought in significant impacts to the society and the threat to immediate food security is on top of the list. The government is highly encouraging home gardening as one of the remedial measures to this situation. The interest of the society in home gardening has drastically increased especially midst of the pandemic. On the other hand, water requirement for home gardening shall contribute to the increase of the domestic per capita water usage in the country. This shall impose additional stress on water utility organizations.
One of the approaches in this regard is to minimize water usage and identify the cost- effective techniques and easily adopted means of reducing water use. Sri Lanka has traditionally been generalized into three climatic zones, namely, wet zone, intermediate zone and dry zone. The dry zone is covering predominantly Northern, Eastern and down South parts of the country. These water conservation techniques are made for Dry zone areas of Sri Lanka.
There are many crop types suitable for dry zone areas. Vegetables/crops such as ginger, turmeric, brinjal, chili, beans and sprout spinach shall be planted in the home garden in dry zone areas. These are the plants growing tremendously by using the available water from dug well of dry zone areas despite water quality. Ginger and turmeric can be grown to make more income in the small land area whereas brinjal, chili, beans and sprout spinach are grown for day to day use of a family or two.
Required water shall be distributed through the Sprinkler irrigation system to the home garden to minimize the wastage of water. Three Nos. of sprinkler shall be introduced (each shall be covered 4 to 5m radius area) to cover the area of 30-35m2. In the sprinkler method of irrigation, water is sprayed into the air and allowed to fall on the ground surface similar
to rainfall (Fig: 01). The spray is developed by the flow of water under pressure and pressure shall be obtained by pumping by using an agro tube well pump (160ft &0.5HP). The following table illustrates the water and land area requirements to carryout home gardening in an average house having a land extent of 25-30m2 for gardening purposes
Land use pattern of crop/vegetable shall be allocated efficiently to maximize the usage of water with effective and efficient manner as shown in fig.02
There are four techniques used to conserve water while carrying out the home garden as follows;
Technique 1: Introducing Sprinkler irrigation
In this system, water is being sprayed into the air and allowed to fall on the ground surface similar to rainfall. This will most suitable for irrigating crops/vegetables, where the plant population per unit area is very high (same as in the home garden with the small area) and closer control of water application convenient for giving light and frequent irrigation and higher water application efficiency.
Technique 2: Adding more organic matter (cow dung, animal matter, and vegetable matter) to the soil.
Because adding compost to the soil will help reduce the plants' need for water specially in the areas of the dry zone. Increasing the amount of organic matter will quadruple the water holding capacity of the soil.
Technique 3: Using mulches to reduce evaporation.
Mulching helps to reduce evaporation and cool the soil. Mulching can reduce the plant's water needs by a great amount. It is proposed to use straw, which is a great mulch and as it breaks down it will add organic matter to the soil, as layers, about 3-4 inches above the soil. This technique is to cut down on reducing evaporation from the soil and retain water in great amounts. Further straw is gettable for very cheap, even for free of charge in dry zone areas like Vavuniya, Mannar, Polonnaruwa, Anuradhapura, Kilinochchi, Mullaitivu, Jaffna, Batticaloa and Amparai.
Technique 4: Adding charcoal into plant bags/container
By adding a layer of horticultural charcoal to the plant container/bags It will keep the vegetable plants healthy. This will enable retaining water around the roots and providing adequate moisture to the soil. Further, it will protect the plant against bacteria, fungus and rot. It also helps to eliminate odours.
Water shall be metered daily as shown in fig.03 and shall be recorded in order to ensure the precious usage of water
Followings are the photograph to show the home gardening which is already implemented and in operation at present.
Pic 02: Crops Growth from Seeds to Plant
Pic 03: Plantation of Crops in Containers with Sprinkler irrigation
BSc.Eng.(Hons), MBA, CEng., MIE(SL), GREEN SL® AP, MSLAAS
Chief Engineer (Sector Planning),
Regional Support Centre (North),
National Water Supply & Drainage Board