ISHS Acta Horticulturae 819: International Symposium on Growing Media 2007
EVALUATION OF THREE METHODS FOR DETERMINATION OF STABILITY OF COMPOSTED MATERIAL DESTINED FOR USE AS A COMPONENT OF GROWING MEDIA |
| Authors: | D. NiChualain, M. Prasad |
| Keywords: | compost, Dewar, Oxitop®, Solvita™, greenwaste |
| Abstract:
Comparative studies were undertaken to evaluate three compost stability determination methods; Dewar self heating, Solvita™ and a pressure sensor method (OUR/Oxitop®). Criteria studied included the relationship between the three methods; the relationship with the duration of the composting process (not on one windrow but on a number of windrows); and a comparison of the three analytical methods. As the duration of the composting progresses, a drop in pile temperature occurs as a result of microbial activity, hence a number of researchers have used the relationship between temperature and duration of the composting process to evaluate the efficacy of a particular test. In addition, if the respiration is related to temperature, and since temperature is microbially mediated, a relationship with pile temperature profile would give an indication of microbial activity. In this trial three methods, Solvita™ kit, the OUR method and a self heating test were used to determine the stability of composting piles, destined for use in growing media, at various stages of composting. The piles were made up of greenwaste and spent brewery grains, and were sampled during composting and degree of stability determined. Each method was compared and the relationship between stability determination and pile age was determined. An increase in compost stability was observed with all methods. One method-the self heating test, indicated compost stability had been reached after 6 weeks; OUR and Solvita™ had identified the piles as stable after 9 weeks. The methods showed good correlations with pile age. There were good correlations between the self heating and Solvita™ methods, self heating and OUR, and OUR and Solvita™. | |
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