Programación de riego en cítricos en base a sensores de medida del estado hídrico del suelo y de la planta

Abstract

An experiment on regulated deficit irrigation (RDI) strategies was performed during 2004 in an orchard of ‘Clementina de Nules’/’Citrange carrizo’ In Valencia Spain. Three different irrigation scheduling protocols were compared. Two approaches were based on the information derived from the plant and a third one managed on a sustained, fixed deficit application. Deficit irrigated treatments were compared to a well-watered control treatment, irrigated at 100% of a weighting lysimeter evapotranspiration (ETlis) located in the same orchard. Water restrictions were applied during the fruit growth period after June fruit drop, from July to October, and during the rest of the year all treatments were irrigated at 100% ETlis. Irrigation management based on plant measurements consisted of a variable application rate in order to maintain the maximum daily stem contraction close to 125% and 135% of MDS value of control treatment (MDS ratio management). Finally, the third deficit irrigation treatment was irrigated at 52% of ETlis during the whole restriction period. The results show that was possible to schedule irrigation based on MDS information in order to maintain the MDS ratio respect to the control around the preset values of 125% and 135% respectively. Yield and number of fruit per tree was significantly lower (p <0,05) respect to control the RDfixed and MCD1,35, but not in the MCD1,25 treatments. Fruit size distribution and fruit quality in all treatment did not differ significantly (p <0,05) respect to control, despite the water saving achieved, which ranged from 12 to 19%, on an seasonal basis.