Effect of water management strategies on two vegetable crops under a Bhungroo irrigation technology in Upper East Region, Ghana

Abstract

Exploring options to access water for irrigation and water management strategies at the field level is pivotal for improving crop yield and water productivity. Farmer-participatory field trials were conducted in Gorogo and Sepaat communities, Upper East Region, Ghana, in the 2020/2021 and 2021/2022 irrigation seasons to evaluate the yield response of tomato and onion crops to varied levels of deficit irrigation using Bhungroo irrigation technology. The experimental factor was water application depth at four levels: 65, 85, and 100% of crop water requirement (CWR) and farmers’ discretion. Irrigation water productivity (IWP) was computed as a function of the yield and water applied. Seasonal water used in the tomato fields ranged from 232 to 502 mm, while the onion trials varied from 358 to 750 mm. The fresh fruit yield of tomato ranged from 6.0 to 17.5 t ha−1 in the two seasons, while the dry onion bulb yields ranged from 15.2 to 25.4 t ha−1. The IWP ranged from 2.11 to 3.61 kg m−3 for tomato and from 2.05 to 4.51 kg m−3 for onion. The lowest values were obtained from the least water applied, while the highest values were obtained from the highest. The deficit irrigation schedules significantly decreased both yield and IWP compared to 100% CWR in tomato and onion, while the farmers’ discretion led to over-irrigation in both study locations. It is recommended that tomato and onion crops be irrigated to meet the full crop water requirement in the study areas.