Crop Diversification in the Asia-Pacific region - United Nations in ...

CROP DIVERSIFICATION IN SRI LANKAS.S.B.D.G. Jayawardane * and L. A. Weerasena **1. INTRODUCTIONSri Lanka is an island in the Indian ocean located between 79 o 50’ and 82 o longitudeand 6 o and 9 o 50’ latitude. The total land area of the island is 6.5 million hectares and thepopulation is 19 million.The extent of irrigable land in the country has been increased to 483,000 ha including80,000 ha of well drained upland with the commissioning of lands under the Mahaweli riversystem and other major irrigation schemes in the post independence era resulting in abreakthrough in rice production. Sri Lanka has become nearly self-sufficient in riceproduction. However, cultivation of rice in well drained soils in major irrigation schemes isconsidered to be a waste of irrigation water due to high percolation rates observed.Cultivation of non-paddy crops in the well drained soils could save water and thus pave theway for crop diversification in major irrigation schemes.The cost of rice production has increased tremendously during the past few decadesand consequently rice production has become uneconomical in marginal rice lands,especially in the wet part of the island. Therefore, more lands have become available forcrop diversification. The potential areas of crop diversification in the island are found indifferent ecological settings. Cultivated crops and cropping patterns adopted vary with theagro-ecological conditions. Hence, the definition of crop diversification contains anextensive meaning for Sri Lanka. Thus it could be defined as the cultivation of alternativecrops or adoption of alternate cropping patterns instead of traditional crops and croppingpatterns.1.1 ClimateSri Lanka is located in the tropical belt of the world climatic map. The central hillsof the country divide Sri Lanka into three major climatic zones by acting as a barrier to themonsoon winds. The three major climatic zones are named as wet, intermediate and dryzones which receive an average annual rainfall of >5000-2500 mm, 2500-1750 and 1750-900 mm, respectively. Further, three main regions in the island have also been identified,based on elevation, namely, the low country (0 – 300 m), mid country (300 – 900 m) and upcountry (>900 m). These climatic zones are further sub-divided into 24 agro-ecologicalregions, each one being more or less uniform in climatic conditions and in soils. Majorirrigation schemes are predominantly found in the dry zone and a few are found in the othertwo zones. Rainfed wetland rice cultivation is mainly practiced in the wet zone.* Director General of Agriculture, Department of Agriculture, Peradeniya, Sri Lanka.** Deputy Director (Research), Regional Agriculture Research Centre, Angunakolapellessa, Sri Lanka.112