Conservation farming practices for small reservoir watersheds: a case study from Sri Lanka
Traditional agricultural villages in the dry zone of Sri Lanka are minor watersheds where small earth bank reservoirs provide water for irrigation and domestic purposes. The farmers practise rainfed farming on a shifting basis called chena in the reservoir catchments, which are being degraded due to soil erosion. The consequent sedimentation in reservoirs has reduced the extent of irrigation, and the total farming system has lost its ecological balance and economic sustenance. The present study aimed at identifying suitable farming methods for reservoir catchments in order to prevent further deterioration.
The investigation was carried out on plot basis to assess soil loss and runoff from forest, scrub and cultivated lands as well as from four other types of farming lands namely plough-farming, bund-farming and two conservation farming practices: strip mulch and graded hedgerow farming. In graded hedgerow farming hedgerow trees are planted across the slope with a mild gradient of 0.4–0.5%. The study was carried out in a reservoir watershed at Maha Illuppallama, Sri Lanka during 1989/90 major rainy season.
Results indicated that the two conservation farming practices generate 33–34% annual runoff while replenishing soil moisture of the watershed. Soil loss data showed that the conservation farming practices provide more than 80% protection against soil erosion while bunding can provide only 40% protection compared to existing shifting cultivation practices.
Key wordssoil erosion runoff shifting cultivation strip-mulch farming hedgerow farming agroforestry Universal Soil Loss Equation (USLE)
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- Dent FJ (1984) Land degradation: present status, training and education needs in Asia and the Pacific. In: Janatawat S (ed) Proceedings of the International Workshop on Soil Erosion and Its Counter Measures, Chianmai, Thailand, pp 27–43Google Scholar
- Dharmasena PB (1989) Optimum utilization of the storage in village tanks. Trop Agric, Dept of Agriculture, Sri Lanka 145: 1–11Google Scholar
- Dharmasena PB (1991) Present use of land and water resources in village tank farming. J Soil Sci Soc Sri Lanka 7: 1–17Google Scholar
- Dharmasena PB (1992) Soil erosion control measures for rainfed farming in the dry zone of Sri Lanka. PhD thesis, University of Peradeniya, Peradeniya, Sri Lanka, 133 ppGoogle Scholar
- Handawela J and Kendaragama KMA (1991) Effect of Gliricidia sepium on upland soil fertility in the dry zone of Sri Lanka. In: Gunasena HPM (ed) Proceedings of 2nd Regional Workshop on Multi-purpose Trees, University of Peradeniya, Kandy, Sri Lanka, pp 50–59Google Scholar
- Joachim AWR and Kandiah S (1948) The effect of shifting (chena) cultivation and subsequent regeneration of vegetation on soil composition and structure. Trop Agric, Dept of Agriculture, Sri Lanka CIV: 3–11Google Scholar
- Moormann FR and Panabokke CR (1951) Soils of Ceylon. Trop Agric, Dept of Agriculture, Sri Lanka CXVII: 3Google Scholar
- Roberts RW (1980) Report No. 1 of the Land Use Planning Team, Pilot Dryland Farming project, Muthukandiya Reservoir Scheme, Sri LankaGoogle Scholar
- Senevirathne Banda KM, Kendaragama KMA and Sangakkara UR (1993) Root distribution of Gliricidia and Leucaena trees and maize in an alley cropping system. In: Gunasena HPM (ed) Proceedings of 4th Regional Workshop on Multipurpose Trees, University of Peradeniya, Kandy, Sri Lanka, pp 155–159Google Scholar
- Thilakasiri SL (1986) Village irrigation. Economic Review, Peoples Bank, Colombo, Sri Lanka 2 (II): 3–15Google Scholar
- Udawattage UDS (1985) The Development of Micro Catchments in Sri Lanka. J Hydrol 80(198): 351–359Google Scholar
- Weerakoon WL (1982) Managing a sustainable farming system in Sri Lanka. Proceedings of British Crop Protection Conference — Weed 1982, UK, pp 689–696Google Scholar
- Wischmeier WH and Smith DD (1965) Agricultural Handbook No 282. USDA, USAGoogle Scholar