Water use efficiency of orange-fleshed sweetpotato ( Ipomoea batatas L. Lam.)

Abstract

The objectives of this research were to assess the yield response of orange fleshed sweet potato to water supply at different frequencies; to evaluate how beta carotene content and nutritional water productivity of orange fleshed sweet potato will be affected by water supply at different frequencies and; to calibrate and validate the Soil Water Balance (SWB) model for orange fleshed sweet potato. A field trial was established in December 2011 at the University of Pretoria experimental Farm (Hatfield, Gauteng Province), under a rainshelter. The trial comprised of four irrigation regimes namely, Ttw (irrigated twice a week), Tow (irrigated once a week), Totw (irrigated once in two weeks) and Tdryl (rain and supplemental irrigation dependent). Tdryl, an independent field block, was established outside the rain shelter. Growth and yield analyses were carried out during the growing season. Irrigation was applied to field capacity (FC), depending on water required by each treatment, as determined with a neutron probe three times in a week.