ISHS Acta Horticulturae 99: Symposium on Substrates in Horticulture other than Soils In Situ
A PROCEDURE FOR DETERMINING AIR AND WATER CAPACITY OF SOILLESS MEDIA AND A METHOD FOR PRESENTING THE RESULTS FOR EASIER INTERPRETATIONS |
| Authors: | K.M. Goh, E.F. Maas |
| Abstract:
A method is described for the simultaneous determination of the air and water capacity of soilless media. In this method a separate tension funnel is used for each sample. Each funnel is filled with a plaster of Paris - sand mixture and it is connected to the manifold of a tension apparatus in which the tensions are varied using a jack device and water reservoirs. The method is highly reproducible as evident by an overall mean coefficient of variation of 5. 95 % (range of 2. 21 to 10. 69 %) and an overall mean standard error of means of 0. 55 (2. 40 % of grand mean) and a range of 0. 31 to 0. 84 (0. 97 to 5. 34 % of grand mean). The cited statistical estimates were obtained from an experiment using fir sawdust and fir sawdust:fine peat mixtures. The results from the experiment are also presented by a method which allows easier interpretations with direct reading from water release curves values of air and water capacity of soilless media. In this method water release curves are plotted with the 10 cm tension as the base line for zero water content and zero air space. | |
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