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Monitoring nutrient turnover during composting has to be based on a constant reference parameter. Is total ash content really a good choice?

Raupp, Dr Joachim (2002) Monitoring nutrient turnover during composting has to be based on a constant reference parameter. Is total ash content really a good choice? In: Thompson, Robert (Ed.) Proceedings 14th IFOAM Organic World Congress, p. 66.

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Summary

The total ash content is usually considered to be fairly constant during the composting period, apart from addition of minerals by precipitation and losses by seepage. However, our field trials with farmyard manure have shown that the ash fraction insoluble in hydrochloric acid increased much more than the soluble fraction in the same time. If changes are merely caused by composting intensity (e.g. organic matter degradation), both fractions should be accumulated in the same degree. It is hypothesized that the higher rise of the HCl-insoluble fraction indicates a higher amount of soil material in the heaps at the end compared to the beginning of composting, as the insoluble fraction originates mainly in soil-borne silicates while the soluble fraction is derived from (plant and animal) organic matter. Contamination with soil material could occur when turning the heaps by machine as it has been done several times in this trial. This explanation is supported by our results of another composting study carried out for several years without turning the heaps. No such disproportional changes of the soluble and insoluble ash fractions have been observed under these conditions. It is suggested to use the HCl-soluble ash contents as a reference parameter, at least in field trials without absolutely controlled conditions. The aim of this study was to improve the scientific methods for composting organic materials under practical farming conditions.


EPrint Type:Conference paper, poster, etc.
Type of presentation:Paper
Keywords:farmyard manure; turnover; nutrient losses; parameters
Subjects: Crop husbandry > Composting and manuring
Knowledge management > Research methodology and philosophy > Specific methods
Research affiliation: Germany > Institute for Biodynamic Research - IBDF > Farmyard Manure > Composting of Farmyard Manure and Organic Waste
Deposited By: Raupp, Dr. Joachim
ID Code:619
Deposited On:26 Apr 2003
Last Modified:12 Apr 2010 07:27
Document Language:English
Status:Published
Refereed:Not peer-reviewed

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