ISHS Acta Horticulturae 294: II Symposium on Horticultural Substrates and their Analysis, XXIII IHC
ESTIMATION OF PORE SPACE AND THE CALCULATION OF AIR VOLUME IN HORTICULTURAL SUBSTRATES |
| Authors: | P.L. Waller, A.M. Harrison |
| Abstract:
Based on regression analysis of the results from the physical analysis of 238 horticultural substrates, expressions have been derived which enable both their Pore Space (PS) and Air Volume (AV) to be calculated without determining Particle Density (PD), namely: PS = 96.72 - 0.038VW and AV = 96.72 + 0.062VW - 100DD where VW (Volume Weight) is the ratio of substrate dry weight and drained volume (g/l) and DD (‘Drained Density’) is the ratio of substrate drained or wet weight and drained volume (g/ml). For these calculations only three simple measurements are necessary. For fundamental reasons, the formulae should not be used for those substrates in which there are a high proportion of closed pores, e.g. where polystyrene is present. In these circumstances it is necessary to measure the true PD of the substrate if the Effective Pore Space (EPS) is to be determined and overestimation of the AV is to be avoided. A suitable method is described. | |
Download Adobe Acrobat Reader (free software to read PDF files) | |
