ARTICLE IN PRESS
Biosystems Engineering (2007) 96 (3), 419–425 doi:10.1016/j.biosystemseng.2006.12.002 SW—Soil and Water

Adaptation of an Automatic Irrigation-control Tray System for Outdoor Nurseries
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R. Caceres; J. Casadesus; O. Marfa
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Departament de Tecnologia Hortı´ cola, Institut de Recerca i Tecnologia Agroalimentaries (IRTA), Centre de Cabrils, Cra. de Cabrils s/n 08348
Cabrils, Catalonia, Spain; e-mail of corresponding author: rafaela.caceres@irta.es
(Received 4 April 2006; accepted in revised form 4 December 2006; published online 29 January 2007)

Inefficiency in water and nutrient management in outdoor nurseries causes environmental concerns. In this sense, the irrigation-control system should …ver más…

Bearing in mind that outdoor ornamental plant nurseries grow a wide variety of species and use different formats, strategies to promote water conservation require to consider many different factors, such as the needs of different species, the distribution of growing containers, and the design and maintenance of irrigation systems (Bilderback, 2002; Garber et al., 2002).
To increase irrigation efficiency in a group of homogeneous plants in a nursery (i.e. plants of the same species and of similar size), it is necessary to determine the dosage of water to be applied and the criteria for activating the irrigation system.

Irrigation dosage is based on substrate characteristics, container volume and leachate-fraction percentage
(Salas & Urrestarazu, 2001; Moreno, 2003).
In outdoor ornamental plant nurseries, irrigation is usually activated empirically, which means irrigation dosage and frequency are not based on objective criteria
(Michelot, 2000). It is very common for irrigation to be programmed at regular time intervals without taking into account objective parameters such as substrate moisture (Lieth & Burger, 1989; Biernbaum, 1992). The aim is for irrigation to be activated automatically when plants need it, while bearing in mind water-retention capacity of the substrate and plant water consumption.
Many methods have been described and sensors have been developed that provide reliable information so irrigation can be