Water Use in Drip- and Microsprinkler-Irrigated Citrus Trees

Abstract

Advanced citrus production systems (ACPS) are being evaluated in Florida citrus groves for sustainable, profitable citrus production. The ACPS practices provide tight control over water and nutrient-mediated plant growth and development using irrigation to train the root system into a limited area and fertigate with daily nutrient requirements. Thus, a study was undertaken to (i) compare daily water use using the stem heat balance method on ≤5-yr-old citrus trees using two ACPS irrigation methods (using daily drip and microsprinkler irrigation) and conventional irrigation on two Florida sandy soils; (ii) determine relationships between hourly sap flow and time of day, and daily water use vs. total available soil water in the irrigated zone; and (iii) evaluate the effect of Huanglongbing (HLB) disease on water uptake. The sap flow data suggest that intensive drip and microsprinkler irrigation systems resulted in similar or higher water use than conventional irrigation. Water use was greater (P ≤ 0.01) with ACPS than conventional microsprinkler practice irrigation in summer 2010, spring 2011, and late summer 2011 at the Entisol site. Water use was 29 to 38% greater using ACPS than conventional irrigation in June 2011 at the Spodosol site, albeit, not significantly different. All irrigation systems showed water contents close to field capacity at both sites, indicating that water was nonlimiting in each irrigation system despite having different irrigation schedules. The high water uptake using intensive irrigation systems is ascribed to frequent irrigation and improved water distribution in the irrigated zone.