DEFINING CRITICAL CAPILLARY RISE PROPERTIES FOR GROWING MEDIA: MODEL AND METHODOLOGY
Efficient use of irrigation water is becoming an important issue in nursery and greenhouse production across the world. Different water conserving systems have been proposed with some relying on good substrate capillary rise properties. However, little is known about the appropriate capillary properties of various substrates. Hence, this paper summarizes the different steps that were followed in order to identify the appropriate capillary rise properties for proper plant growth in nurseries. A first step was to develop a model of capillary rise based on the unsaturated hydraulic conductivity curve, the models developed in a second step, and then the models were validated against field data in a third step. Therefore, this conceptual framework is proposed by the authors for assessing the suitability of substrates for plant growth by characterizing the substrate, using the evapotranspirative demand as input, and a model to predict the substrate performance under nursery or greenhouse conditions. Alternatively, a comparison of the unsaturated hydraulic conductivity curve with a chart is proposed as a simpler but less accurate way of assessing the behaviour of substrates prior to nursery use.
Caron, J. and Elrick, D.E. (2008). DEFINING CRITICAL CAPILLARY RISE PROPERTIES FOR GROWING MEDIA: MODEL AND METHODOLOGY. Acta Hortic. 779, 149-154
peat substrates, bark, air-filled porosity, aeration capillary rise, nursery