Articles
INFLUENCE OF PEAT DECOMPOSITION ON THE STRUCTURE AND WATER BEHAVIOUR IN GROWING MEDIA
Article number
891_24
Pages
209 – 214
Language
English
Abstract
The properties of peat are determined by its botanical composition and the degree of decomposition.
During decomposition, various chemical and physical, as well as biological transformations take place in the material.
Decomposition is mainly microbiological degradation of plant material particularly in wet, acidic conditions.
Part of the degradation process is caused by climatic conditions like freezing and thawing.
Due to the humification process, the transformation in the chemical composition proceeds into more stable compounds.
The proportion of hemicellulose and cellulose decreases, and the proportion of lignin and other humus substances increases.
As a consequence of decay, the physical properties of peat change (colour, particle size, cell structure, porosity, wettability, water holding capacity, bulk density). These changes have an influence on the water management, and thus on the usability of the peat.
In many applications, such properties as water uptake, water retention capacity and on the other hand structural stability play a major role.
In this study, the porosity and water adsorption properties of peat of different degrees of decomposition were determined.
Studies were undertaken also concerning the micro-structure of these materials by using scanning electron microscopy (SEM). The peat-water relationship is a fundamental condition in growing media.
When peat is used as a substrate for long term crops or soil improver, the structure and physical properties of peat may change dramatically if it is slightly decomposed.
Weakly decomposed peat qualities are very suitable for short term growing e.g., of seedlings, bedding and pot plants, whereas it is advisable to use more decomposed peat for long term crops and landscaping applications.
During decomposition, various chemical and physical, as well as biological transformations take place in the material.
Decomposition is mainly microbiological degradation of plant material particularly in wet, acidic conditions.
Part of the degradation process is caused by climatic conditions like freezing and thawing.
Due to the humification process, the transformation in the chemical composition proceeds into more stable compounds.
The proportion of hemicellulose and cellulose decreases, and the proportion of lignin and other humus substances increases.
As a consequence of decay, the physical properties of peat change (colour, particle size, cell structure, porosity, wettability, water holding capacity, bulk density). These changes have an influence on the water management, and thus on the usability of the peat.
In many applications, such properties as water uptake, water retention capacity and on the other hand structural stability play a major role.
In this study, the porosity and water adsorption properties of peat of different degrees of decomposition were determined.
Studies were undertaken also concerning the micro-structure of these materials by using scanning electron microscopy (SEM). The peat-water relationship is a fundamental condition in growing media.
When peat is used as a substrate for long term crops or soil improver, the structure and physical properties of peat may change dramatically if it is slightly decomposed.
Weakly decomposed peat qualities are very suitable for short term growing e.g., of seedlings, bedding and pot plants, whereas it is advisable to use more decomposed peat for long term crops and landscaping applications.
Authors
P. Nieminen, O. Reinikainen
Keywords
peat, decomposition, scanning electron microscopy, physical properties, water management
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