Water is the basis of life and the key input in agriculture. All civilizations developed and proliferated along river courses. As population increases, demand for food, fuel, fiber, feed and shelter also increases and the natural resources which supports all of it are dwindling. It is envisaged that the biggest crises in the contemporary world will be water crisis in the form of water scarcity.
Water is the single most important natural resource affecting crop productivity. Majority of our agriculture is rainfed but due to unpredictable rainfall, crop yields are low, highly variable and unstable. Climate change is further increasing the problem with regard to rainfall pattern and distribution.
In Nagaland, out of 1657900 ha total geographical area, about 380222 ha is the net cultivated area and 488522 ha is the gross cultivated area. Only about 19% of the gross cultivated area in the state is irrigated and about 81% is rainfed. On an average Nagaland receives 144.65 mm rainfall in a year, enough to sustain farm needs, but it is often distributed very unevenly and in many cases, crops are unable to use a high proportion as much of it is lost through runoff or leaching. Rainfed agriculture is crucial to the country’s economy and security because about 44% of the total food production is contributed by rainfed agriculture.In this context, the concept of rain water collection/ harvesting and conservation becomes imperative and important to achieve higher goals of optimum or high productivity. The basic principle of rain water harvesting is to ‘catch the water where it falls’. However, in a broader sense, rain water harvesting refers to harvesting water from any available source, and use the harvested water in situ or at adjoining places. Rain water harvesting is the process of collecting, storing and improving the productive use of rainwater, and reducing unproductive depletion. In other words, it involves collection, storage and recycling of rainwater for agricultural, domestic or industrial purposes. Rain water harvesting does not imply harvesting water received directly from rains only, but also from all other natural sources like rivers, streams, lakes, ponds, wells, water springs, groundwater aquifers, etc., as all these sources of water draw water from the rain itself.
Rain water may be harvested and stored in small farm ponds on individual farmer basis (100-200 m³ capacity) or larger reservoirs on community basis. On-farm, i.e., in situ rain water harvesting (through land shaping and inter-terrace runoff collection, etc.) is another approach. The choice depends on the objectives, agro-ecological situation, and people’s willingness and their participation. However, under Nagaland situation it is best to harvest in small farm ponds which is relatively more feasible and practicable.
Water harvested from rains or other secondary sources can be very costly and thus should be used in such a way to give maximum productivity- using for cultivating high value cash crops, such as vegetables, floriculture, medicinal plants, etc. Based on studies and trials, it is found that a 150-200 m³ capacity pond is adequate for cultivating vegetables in about 400 m² area. Further, the water productivity can be increased if harvested rainwater is used for irrigation in conjunction with poly-houses.
Rainfall is the main natural source of water, and we can do very little to modify it, but we can modify/strengthen the secondary sources of water like water springs, ground water, wells, ponds, rivers, etc. efforts should be made to protect the natural water resources against drying, pollution or physical destruction.
