Effects of Irrigation Method on Pollination and Pollinators (Hymenoptera: Apoidea) in an Open-Field Tomato Crop

Abstract

Tomato is one of the highest water-demanding crops, and the use of different irrigation systems and different water management strategies may affect crop yield. Despite the fact that tomato is a self-fertilizing (autogamous) plant, research has shown that bees ("buzz pollination") improve yield and fruit quality. Here, we assess the effect of the irrigation method on bee visitation and pollination on flowers of the tomato crop. The study was conducted from Jul to Oct 2017 in Minas Gerais State, Brazil, using 6 plots with 150 tomato plants per plot. Three plots received water by sprinkler irrigation and the other 3 by drip irrigation, in a randomized complete block design. Bees were sampled from plants watered with both irrigation systems to evaluate visitation rate. Fruit set and fruit weight were compared between irrigation systems. Bee visitation rate was not affected by the irrigation method, and the mechanical impact of the sprinkler did not provide the same level of bee pollination. As pollination and pollinators were not negatively affected, the best irrigation method should take into account agronomic aspects, such as financial viability and water use efficiency. The drip irrigation system seems to be the most effective, because it exhibits these characteristics, even though it may have a higher cost.