Effects of peat compression on expanded volume and other physical parameters
Peat still represents the most important raw material used in Europe by growing media producers in order to prepare substrates for professional users. In an effort to reduce transport costs and overuse of plastic, large number of substrates industries compress and deliver growing media in large packages for the professional market. Final users of substrates or growing media manufacturers complain sometimes with their suppliers about the discrepancy between the declared and the final volume obtained following from the expansion process. The aim of this work was to study the influence of three different pressures applied to peat for compression before shipping. Trials were carried out to evaluate the final expanded volume, and other physical parameters, using peats with two degrees of decomposition, two moisture content values and different granulometry of particles. Results obtained showed a direct correlation between applied pressure and loss of expanded volume expected when peat is decompressed for final use. Furthermore, the influence of pressure was highest in peat with the lowest degree of decomposition, the coarsest structure of particles and the lowest content of water. Pressure applied affected principally the volume of air, the amount of easily available water and buffering water capacity; to a lesser degree the shrinkage and the bulk density. Finally, negligible effects were observed on total porosity and water retention.
Cattivello, C., Mattiussi, A. and Spessot, M. (2019). Effects of peat compression on expanded volume and other physical parameters. Acta Hortic. 1266, 153-158
air volume, granulometry, pressure, degree of decomposition, moisture content