Title: Water Use Efficiency and Yield Response of Ocimum Gratissimum (Scent Leaf) under Porous Pot Sub-Surface Irrigation in a Naturally Ventilated Polyhouse.
Authors: Theodora O. Ohajesi, Celestine C. Egwuonwu, Maxwell I. Chikwue, Gladys U. Asonye, Tochukwu A. Ihedioha
Volume: 10
Issue: 8
Pages: 184-189
Publication Date: 2026/08/28
Abstract:
Water scarcity, exacerbated by climate variability and increasing agricultural demand, necessitates efficient irrigation technologies for sustainable vegetable production in developing regions. This study evaluates the consumptive use and yield response of Ocimum gratissimum (scent leaf) under a porous pot sub-surface irrigation system in a Naturally Ventilated Polyhouse (NVPH) setting. The experiment involved transplanting nursery-raised seedlings around 16 buried unglazed clay pots at varying spacings (3, 5, 7, and 9 cm) using a Randomized Complete Block Design (RCBD). Soil moisture retention was observed using calibrated dipsticks, while a set of weighable lysimeters was used to quantify actual crop water loss. Climatic data from the Nigerian Meteorological Agency (NIMET) informed the empirical estimation of crop evapotranspiration (ETc) using the Blaney-Morin-Nigeria (BMN) model. Growth parameters-including plant height, stem girth, number of leaves, and leaf area-were recorded across three developmental stages. Water use efficiency (WUE), crop coefficient (Kc), crop water requirement (CWR), and consumptive use were calculated. Results showed a Kc of 0.92, crop water requirement of 171 mm, and consumptive use rate of 0.5 cm/day. Daily crop evapotranspiration averaged 5.3 mm, and water use efficiency reached 90.6%. An optimal irrigation interval of 6 days was recommended. ANOVA indicated no statistically significant differences (P < 0.05) among the treatment means. These findings demonstrate that the porous pot sub-surface irrigation method is effective for water-saving and yield enhancement in the cultivation of Ocimum gratissimum under controlled environments.