Planning for sustainable agriculture in Ghana using tank irrigation
2000
Amu-Mensah, F.K. (Tottori Univ. (Japan)) | Yamamoto, T. | Inoue, M.
Using soil, crop and climate data from three agro-ecological zones of Ghana and rainfall-runoff coefficients from Niger, the authors, show by computer simulation, that tank irrigation offers a sustainable alternative to rainfed agriculture in Ghana. Water balance of rainwater catchment apron, water storage tank and a 350 squire-meter-cultivated field is simultaneously carried out bounded by the condition that the tank does not empty during the period of simulation. Suitable apron areas are determined for three crops grown under different climates with sprinkler and drip irrigation. Results indicate that drip irrigation economies on apron area by as much as 41% in the case of citrus, 22% for Tomato and 28% for maize compared to sprinkler. Optimum tank capacities are also economized by over 40%. This is attributed to reduced field evapotranspiration under drip irrigation. Irrigation type makes little difference to apron area under moist conditions, because then, drip behaves similarly to sprinkler irrigation. Small tank capacities produce excessive tank overflows which, are aggravated in sprinkler irrigation. Low rainfall years also force the system to have large apron areas that cause excessive overflow in good rainfall years
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