English

Abstract

In the face of increased competition for water resources, optimal irrigation scheduling is necessary for sustainable development of irrigated agriculture. However, the most favourable irrigation scheduling has many constraints and conflicting objectives and deals with an environment which has a lot of uncertainty. In this study, a comparative approach was undertaken for irrigation scheduling using Aquacrop 5.0 and the Cropwat 8.0 FAO models using data from a case study at Thornpark station, University of Zimbabwe, Zimbabwe from 2014 to 2017 in which the maximum net benefits of yield and water use efficiency were obtained based on soil, crop, meteorological data, normalised CO2 and field management. The maximum irrigation requirement predicted by Aquacrop was at 555.3 mm, for Cropwat it was at 675.0 mm per cropping season. The yield predicted by the Cropwat model was 2.93 t h-1a versus a yield of 3.40 t h-1 for Aquacrop. The water productivity stood at 0.94 kg m-3 for Cropwat and for Aquacrop it was at 0.97 kg m-3. Under the scenarios presented and other conditions of study, Aquacrop 5.0 produced optimum results for a tomato crop during the hot and dry season in Harare. Key words: Water productivity, drought, dynamic climate data, precision irrigation, precision agriculture, Cropwat, AquaCrop.