Estimation of crop evapotranspiration of Okra using drainage Lysimeters under dry season conditions

Abstract

Water scarcity is a major constraint to dry season vegetable production in Sub-Saharan Africa. Therefore, crop evapotranspiration (ETc) and fresh pod weight (FPW) of okra were determined over two cropping seasons for water management in dry season irrigated farming. Two commonly grown okra varieties (NH47–4 and UI4–30) in Nigeria were investigated under three reference evapotranspiration (ETo) rates (High: ETo-H, Medium: ETo−M and Low: ETo-L) in a 2 × 3 factorial experiment using drainage lysimeters. The average ETc of UI4–30 (2.46 mm day−1) and NH47–4 (2.39 mm day−1) did not differ significantly and ranged from 1.00 mm day−1 (ETo-L) to 3.97 mm day−1 (ETo-H) and 1.04 mm day−1 (ETo−M) to 3.62 mm day−1 (ETo-H), respectively. Okra ETc was in the order: 2.89 mm day−1 (ETo-H) > 2.33 mm day−1 (ETo−M) > 2.04 mm day−1 (ETo-L). Average okra FPW over two cropping seasons was higher by 13.0% in UI4–30 than NH47–4, and had the largest strong positive correlation with ETc (r = 0.905*). UI4–30 appears superior to NH47–4 in efficient water use for high yield production, while high okra yield production during dry seasons might require a variety with high crop evapotranspiration.