Economic Evaluation of Rainwater Harvesting and Conservation (RWHC) Technologies for Sweet Potato Cultivation in Sierra Leone
International Journal of Agricultural Economics
Volume 4, Issue 3, May 2019, Pages: 94-100
Received: Mar. 7, 2019;
Accepted: Apr. 26, 2019;
Published: May 29, 2019
Views 517 Downloads 85
Patrick Andrew Sawyerr, Department of Soil Science, School of Agriculture, Njala University, Njala, Sierra Leone
Osman Nabay, Sierra Leone Agricultural Research Centre, Njala Agricultural Research Centre, Njala, Sierra Leone
Keiwoma Mark Yila, Sierra Leone Agricultural Research Centre, Njala Agricultural Research Centre, Njala, Sierra Leone
A field trial was conducted to evaluate the economic performance of rainwater harvesting and conservation (RWHC) technologies for sweet potato cultivation in Sierra Leone during five intensive cropping seasons (2014 second – 2016 second cropping season) at the on-station research site of the Njala Agricultural Research Centre. The experiment was laid out in a randomized complete block design in three replications following a factorial combination of two levels of mulch (no mulch and mulch) and three levels of RWH structures (open ridge, tied ridge and arch ridge). Six RWHC technologies evaluated: open ridge without mulch (OR-M), open ridge with mulch (OR+M), tied ridge without mulch (TR-M) and tied ridge with mulch (TR+M), arch ridge without mulch (AR-M) and arch ridge with mulch (AR+M). Profitability (gross margin, net income and breakeven), investment (NPV, IRR and BCR) and sensitivity analyses (25% root yield loss and 10% fall in the market price of sweet potato roots) were used to evaluate the economic performance of the RWHC techniques. The TR+M (SLL 2,091,280) had the highest net income followed by the AR-M (SLL 693,640) and AR+M (SLL 2,218,160) RWHC technologies. The traditional OR-M was not profitable (SLL -2,487,760) for sweet potato cultivation. Based on the cost of production, the OR-M, OR+M, and TR-M RWHC technologies require a root yield increase of 50.5%, 3.0% and 35.4% to breakeven. The AR+M had the highest and positive net seasonal cash flow returns throughout the five cropping seasons. The breakeven point on the net season seasonal cash flow returns for the TR+M, AR-M and OR+M RWHC technologies was in the 2015 main cropping season. At discount rates of 10%, 15%, 20% and 25% the highest NPV was obtained from the AR+M followed by the TR+M and AR-M RWHC technologies. The highest IRR was obtained from the AR+M (111%) followed by TR+M (84%) and AR-M (61%). The AR+M, TR+M and AR-M RWHC technologies had benefit-cost ratios greater than 1. Under uncertain conditions of 25% root yield loss and 10% fall in the market price of sweet potato roots, the AR+M and TR+M are the most profitable RWHC technologies that could be invested in. These technologies should, therefore, be promoted for adoption through on-farm trials in order to enhance intensive sweet potato cultivation on upland gravelly soils in Sierra Leone.
Patrick Andrew Sawyerr,
Keiwoma Mark Yila,
Economic Evaluation of Rainwater Harvesting and Conservation (RWHC) Technologies for Sweet Potato Cultivation in Sierra Leone, International Journal of Agricultural Economics.
Vol. 4, No. 3,
2019, pp. 94-100.
Barros, V. R., Field, C. B., Dokken, D. J., Mastrandrea, M. D., Mach, K. J., Bilir, T. E., Chatterjee, M., Ebi , K. L., Estrada, Y. O., Genova, R. C., Girma, B., Kissel, E. S, Levy, A. N., MacCracken, S., Mastrandrea, P. R., White, L. L., Niang, I., Ruppeln, O. C., Abdrabo, M. A., Essel , A., Lennard , C., Padgham, J., & Urquhart, P. (2014). Africa, climate change 2014: impacts, adaptation, and vulnerability. Part B: regional aspects. Contribution of working group II to the fifth assessment report of the intergovernmental panel on climate change. Cambridge University Press, Cambridge, pp 1199–1265.
Critchley, W. & Gowing, J. (2012). Water harvesting in Sub-Saharan Africa Routledge 2 Park Square, Milton Park, Abingdon, Oxon OX14 4RN.
Lal, R. & Stewart, B. A. 2013. Principles of Sustainable soil management in agroecosystems. Advances in Soil Science. CRC Press. Taylor and Francis Group. Boca Raton. London, New York.
Oweis, T., & Hachum , A. 2009. Water harvesting for improved rainfed agriculture in the dry environments. Integrated Water and Land Management Program, International Center for Agricultural Research in the Dry Areas ICARDA), Aleppo, Syria.
Nedunchezhiyan, M., Byju, G. & Jata, S. K. (2012). Sweet Potato Agronomy. Fruit, Vegetable and Cereal Science and Biotechnology. Global Science Book.
Oweis, T., Hachum, A. & Bruggeman, A. (eds) 2004. Indigenous Water Harvesting Systems in West Asia and North Africa, ICARDA, Aleppo, Syria.
Rockstrom, J., Barron, J., Fox, P. (2002). Rainwater management for increased productivity among smallholder farmers in drought-prone environments. Physics and Chemistry of the Earth. 27, 949–959.
Kassali, R. (2011). Economics of Sweet Potato Production. International Journal of Vegetable Science. Vol 17, 2011, Issue 4 Pages 313-321.
Hatibu, N., Mutabazi, K., Senkondo, E. M. & Msangi, A. S. K. (2006). Economics of rainwater harvesting for crop enterprises in the semi-arid areas of East Africa. Agricultural Water Management 80,74-86.
Yuan, T., Fengmin, L. & Puhai, L. (2003). Economic analysis of rainwater harvesting and irrigation methods, with an example from China. Agricultural Water Management 60 217–226.
Kunze, D., 2000: Economic Assessment of Water Harvesting Techniques: A demonstration of Various Methods. - Quarterly Journal of International Agriculture 39 (1): 69-91.
Senkondo, E. M. M., Msangi, A. S. K., Xavery, P., Lazaro, E. A. and Hatibu, N. (2004). Profitability of Rainwater Harvesting for Agricultural Production in Selected Semi-Arid Areas of Tanzania.