ISHS Acta Horticulturae 801: International Symposium on High Technology for Greenhouse System Management: Greensys2007
RELATIONSHIP BETWEEN SOLIDITY RATIO, COLOUR AND SHADING EFFECT OF AGRICULTURAL NETS |
| Authors: | S. Castellano, A. Candura, G. Scarascia Mugnozza |
| Keywords: | permeable coverings, radiometric properties, transmittance, porosity, HDPE nets |
| Abstract:
In order to investigate the influence of agricultural nets construction parameters on their shading effect, a set of field tests were performed by means of a spectroradiometer, with an acquisition in the solar radiation range, on 12 different kinds of agricultural nets used as shading and anti-hail. On the same kind of nets, shading factor were measured in laboratory by means of an experimental set-up, based on the Italian UNI10335 which, actually, is the only national standard in Europe providing a methodology to evaluate nets shading factors. Measurements highlighted differences between shading factors calculated by means of UNI10335 provisions and the transmittance measured in open field depending on the following parameters: the influence of net construction parameters; the haze effect in real structures; the differences between the artificial source assigned by the standard and the solar radiation; the distance “d” of the sample from the light source. An analytic correlation was found between the porosity and the shading effect and correlation factors were introduced in order to correlate field test results with those obtained by the standard UNI methodology. | |
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