Comparison of methods to automatically activate irrigation systems for shrub species grown outdoors in containers.

摘要

In general, irrigation systems in nurseries where ornamental plants are grown outdoors in containers are not activated based on objective criteria. When the irrigation system is also used to supply nutrients to plants, the result is inappropriate management of plant irrigation and nutrition in that plants either receive too little or too much of both, water and nutrients. However, a technology is available on the market that can be applied or adapted to this kind of nursery to activate irrigation systems using objective criteria. Optimum irrigation management leads to appropriate plant growth and also limits the generation of leachates, which can pollute the groundwater. These irrigation-activation methods are based on measurements of environmental parameters, the water content of the substrate and the plant's water consumption. The main objective of this study was to compare the effects of four kinds of automatic irrigation management on the growth of a shrub species, the laurustinus (Viburnum tinus L.). The following methods of irrigation activation were applied: activation based on tensiometer readings of the matric potential; activation based on water consumption, as detected by an irrigation-control tray adapted to plants grown outdoors in containers; activation when a preset amount of accumulated radiation is reached; and a combined method consisting on activation when a preset amount of accumulated radiation is reached, but only when the matric potential is low enough. The tensiometer and irrigation-control tray methods were more restrictive with irrigation and this limited plant growth. Leachate percentages in the treatments where irrigation was somehow conditioned by measurement of the matric potential were the lowest of all 4 treatments. The treatment that combines climatic parameters with substrate-moisture parameters may limit water use without excessively limiting production.