Regulated deficit irrigation in `Clementina de Nules' citrus trees. I. Yield and fruit quality effects

Abstract

SummaryAn experiment on Regulated Deficit Irrigation (RDI) was performed during 1995 and 1996 in a ten year old, drip-irrigated `Clementina de Nules' mandarin orchard in Moncada, Spain. Treatments consisted of a control, where irrigation was applied without restriction during the whole year at 125% ETlys and RDI treatments where irrigation was reduced to 25% or to 50% of crop evapotranspiration measured by a weighing lysimeter (ETlys) during one of the following periods: I) flowering and fruit set (spring, 20 March to 3 July in 1995, and 1 April to 1 July in 1996); II) initial fruit enlargement phase (summer, 4 July to 7 August in 1995, and 2 to 28 July in 1996), and III) final fruit growth and maturation phases (end of summer–autumn, 8 August in 1995, and 29 July in 1996 to harvest). An additional treatment, denominated 50%–Year, was irrigated at 50% ETlys during the whole year. The effects of the treatments on yield and fruit quality in relation to tree water status (pre-dawn (ca) and midday (cmd) leaf ...