Author(s)

A. Y. Arku, S. M. Musa & A. L. E. Mofoke

Abstract

Crop water requirements and irrigation timing are particularly important in arid and semi-arid regions where water is scarce. In this paper, theoretical crop water requirements and irrigation timing for Amaranthus hybridus in Maiduguri metropolis, north-eastern Nigeria were determined under drip irrigation for the dry season. Reference evapotranspiration (ETo) was based on the Penman- Montieth formula and CROPWAT 8.0. An elemental irrigated area (Ai), crop canopy factor (Cp) and emitter application rates (ar) at each growth stage, were assumed. The highest reference evapotranspiration (ETo) of 6.6 mm day-1 was obtained in May while the lowest of 3.7 mm day-1 in December compared to other months. Also, water requirement (WR) values were computed based on the Freeman Garzoli correction factors. At 30%, 60% and 100% crop canopy coverage, peak water requirements (WR) of 0.7, 1.8, 2.3 L day-1 and low values of 0.4, 1.0, 1.3 L day-1 were obtained in May and December respectively. Emitter application rates of 0.5, 1 and 1.5 Lh-1 resulted to longest irrigation time (Tirrig.) of 1.4, 3.7, and 3.9 h day-1in May while shortest irrigation were 0.3, 0.7 and 0.9 h day-1 in December for early, development and maturity stages respectively. Keywords: water requirements, drip, irrigation, evapotranspiration, emission, crop, coefficient, conservation, timing, arid, scarce.

Keywords

water requirements, drip, irrigation, evapotranspiration, emission, crop, coefficient, conservation, timing, arid, scarce.