Irrigation water strategies to intensify vegetable production on smallholder farms in Guyana

Abstract

As part of its development program, Guyana is diversifying and expanding its agricultural sector to increase the production of higher-value vegetable crops. Apart from ensuring food security, this also reduces the country's food import bill. Abandoned sugarcane lands are targeted for the intensification and expansion of vegetable production. This study seeks to determine the supplemental irrigation requirements of vegetable farms located along coastal lands, recommend scenarios to manage water during the two annual dry seasons, and understand the effects of irrigation thresholds on the yields of six commonly planted vegetables. The AquaCrop model was used for this purpose, together with inputs of field-measured soil and climate data obtained from 2005 to 2012. Yield simulations of seven irrigation thresholds (40, 50, 60, 70, 80, 90, and 100% total available water [TAW]) were evaluated. At 40, 50, and 60% TAW, a decreasing irrigation requirement did not significantly reduce yield (pairwise t-test, p > 0.05). The use of 40, 50, or 60% TAW irrigation thresholds during the two annual dry seasons is recommended. The low irrigation requirements for vegetables do not compete with the water requirements of rice and sugarcane production.