ISHS Acta Horticulturae 172: Composts as Horticultural Substrates
COMPARATIVE STUDIES ON THE EFFECT OF SOIL CONDITIONERS ON THE BIOLOGICAL ACTIVITY OF ORGANIC WASTES |
| Authors: | N. Salem, O. Verdonck, M. De Boodt, J. Timmerman |
| Abstract:
A laboratory study was conducted to investigate the influence of soil conditioners on the biological activity of organic wastes in terms of oxygen consumption and carbon dioxide production. Egyptian sandy soil was mixed with three types of organic matter (El-Khanka fertilizer, Farm yard manure and rice straw) at rate of 5 % on dry matter. The soil mixed with the first and the second mentioned organic matter were thoroughly mixed with soil conditioners (bitumenous emulsion, polyacrylamide, ureaformaldehyde and rice straw). The following experiment was carried out. Incubation experiment under constant temperature, relative humidity and final 10 % moisture content. The aim of this experiment is, to investigate the effect of ureaformaldehyde, free formaldehyde and polyacrylamide on the biological activity as a function of time. The results show that, addition of soil conditioners reduce the biological activity in the first week. This activity increases gradually with respect to the control over the first 3 months. The presence of free formaldehyde in the non fully polymerized ureaformaldehyde is responsible for retarding effect on the biological activity. The highest values of oxygen consumption and carbon dioxide production is observed, when rice straw is added and the moisture content is adjusted at 17 % by weight. Thus great microbiological activities, means high consumption of the organic matter. The values of oxygen consumption and carbon dioxide production is decreased when the moisture content is decreased from 17 % to 10 % by weight. The mechanisms of these effects on the biological activity are discussed. | |
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