Aboveground–Belowground Community Ecology

Abstract

The country has an annual rainfall between 750 and 6,000 millimeters (mm), with large spatial and temporal variation. The availability of clean drinking water is a national imperative, but agriculture consumes the bulk of available water resources. Economic development, population pressure and rising demands from different sectors are placing increasing pressure on available water resources. Climate change could aggravate this situation in Sri Lanka. There is a danger that the demand for water will outstrip supply, particularly in the Dry Zone of Sri Lanka where most irrigation schemes are located. Sri Lanka: Issues and opportunities for investment I Key water issues Revitalizing irrigation There are over 600,000 hectares (ha) of irrigated farmland in Sri Lanka. Cultivation takes place during the two seasons with an average cropping intensity of 1.65. The main irrigated crop in the country is paddy (94% of irrigated area), with an average yield of 4.3 tonnes (t)/ha, and a surplus is being produced at the moment. While the current productivity ranges between 0.2-0.5 kilograms (kg)/cubic meter (m 3), the irrigation efficiency at systems level is about 35-45%. There is a growing need for substantial investment in the rehabilitation of existing irrigation facilities and overall improvements in productivity. Therefore, future investment in the irrigation sector needs to be more focused on increasing productivity of expensive irrigated water through increased yields and multiple use.