ISHS Acta Horticulturae 37: I Symposium on Artificial Media in Horticulture
SOME PHYSICAL AND CHEMICAL CHARACTERISTICS OF LOAMLESS POT-PLANT SUBSTRATES AND THEIR RELATION TO PLANT GROWTH |
| Author: | A.C. Bunt |
| Abstract:
The effect of the ratio and grades of peat and sand on the total porosity, air capacity, bulk density and easily available water in the substrate has been examined. An increase in the particle size of the sand increased the air capacity much more than an increase in the grade of the peat, the volume of water available at low tensions was correspondingly reduced. Plants receiving an excessive number of irrigations showed a progressive reduction in growth as the air capacity of the substrate was reduced below 10 %. Approximately 83 % of the mineral N, 70 % of the K and 60 % of the P in peat-sand substrates could be lost by leaching, the rate of loss being an exponential function of the volume of leachate. Inclusion of vermiculite in the substrate significantly reduced the rate of loss. Of the several slow-release fertilisers examined, crotonylidene diurea had a much slower rate of mineralisation than hoof and horn whilst coated fertilisers had a more rapid release rate than hoof and horn. | |
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