ISHS Acta Horticulturae 481: International Symposium on Growing Media and Hydroponics
CHARACTERISATION OF THE HYDROPHYSICAL AND MECHANICAL PROPERTIES OF PRESSED BLOCKS FOR TRANSPLANTING |
| Authors: | G. Wever, E. Eymar |
| Keywords: | Hypol®, peat, stonewool, texture profile analysis, transplant production |
| DOI: | 10.17660/ActaHortic.1999.481.9 |
| Abstract:
The use of pressed peat blocks to raise plants is a very common system for transplant production. These blocks are usually placed on the soil or on a substrate. For the use as blocking medium, the substrate should have a good hydrophysical behaviour and aeration and also meet specific mechanical qualities. In particular, the cohesion between the substrate particles determines if the medium can be handled. If there is insufficient cohesion, the blocks fall apart, causing problems with planting and possibly also damage to plant roots. There is no suitable technique available for measuring this quality parameter. A technique based on TPA (Texture Profile Analysis) was developed and tested for different media under various growing conditions. The method was effective in determining the mechanical properties of pressed substrate blocks. The stress measured at peak load during the first compression of the TPA cycles is a good indicator for hardness. For stability, it is important not only to consider the hardness but also the ratio of the peak load (stress) of the second to the first compression (cohesion). Concerning the handling of blocks it is premature to set standards because there is not enough information about the influence of the measured parameters in transplant production. | |
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