The impacts of highland agro wells on Dry Zone land use

Abstract

The inadequacy and unavailability of irrigated water and lack of rainfall are the main barriers to the dry zone farmers in Sri Lanka to maintain their agricultural activities throughout the year. Therefore they have realized the need of an alternative source of water. The strategy was the construction of wells in low lying areas of their degraded high lands including chena lands to tap the shallow ground water to cultivate perennial crops as well as seasonal crops throughout the year. The farmers who have entered this cultivation system at the very beginning, obtained positive results. This was an attractive model to mother farmers. However, the farmers are expanding this agro well based perennial agricultural system. This context provided a unique opportunity to explore this new land use type based on agro wells. Field research for this study was conducted covering 20 agro well based agricultural lands out of the total of 68, in the "Aluth Divul Wewa sub watershed" in Yan Oya watershed, in the dry zone of Sri Lanka. Data were collected using map and aerial photograph interpretation, field mapping, questionnaire survey, interviews and in depth field surveying. The collected data were analyzed using qualitative and quantitative methods including LER value and canopy cover mapping. Aluth Divul Wewa sub watershed is a naturally rich ground water area, because of two mountain ranges situated in the Eastern and the Western boundaries. According to this aspect 100% farmers have constructed agro wells in the vicinity of small tanks or near the dry streams. 65% of agro wells indicate an average water depth of 6-8 ft. during the dry months, and these wells show a mean depth of 24ft, and a mean diameter of 22ft. The chena lands which are situated in low lying areas were the most popular lands for excavating agro wells. As a result of this, chena cultivation decreased down to 22% from 30% between 1994-2004. 95% of farmers have stopped the shifting cultivation and 100% of farmers are using live fences and dry field system for water conservation, and shade management. The land equivalent ratio (LER) has revealed that 90 % of lands represent more productivity and canopy cover has increased up to 41.5 % from 7.9%. These farmers have introduced 27 new tree species.