Sri Lanka is situated between 6 and 10 degrees north of the equator and 80 to 82
degrees east near the southern tip of the Indian sub-continent. It is accorded with a climate
that varies from tropical to subtropical. Based on average annual rainfall Sri Lanka is divided
into three climatic zones: wet, intermediate and dry. These climatic zones are subdivided
into seven major agro-ecological zones by latitude, temperature and landform. Further,
these can be subdivided into 46 well-defined agro-ecological regions, each with its unique
combination of rainfall pattern, elevation, landform, temperature and soil types (Figure 1).
Sri Lanka has an area of 65,610 km2 and a population of 19.9 million, of whom 72 per cent
live in rural areas 22 per cent in urban areas, and the balance of 6 per cent in estates. The
population is increasing at an average annual rate of about 1.1 per cent. The population
density is 317 per km2 and there is an average of ratio of one person to 0.08 ha of
agricultural land.