Mineralization and humification of organic matter in controlled transformation systems

Abstract

Purpose: The transformative processes, mineralization and humification, define the characteristics of organic matter (OM) products. However, there is no single analysis criterion, making the evaluation and understanding of these two transformative processes difficult. The objective of this study was to estimate the factors and dynamics of the mineralization and humification processes of OM in three controlled transformation systems. Method: An experiment was established; mineralization and humification would be analyzed, for an observation period of 196 days of a mixture of bovine manure and pine sawdust. Physical, chemical, and biological parameters were subjected to correlation and main component analysis, differentiating by system and by time. Results: The intensity of mineralization was established as 1 to 84 days in semi-composting and 1 to 112 days in composting. Humification was established as 28 to 196 days in semi-composting and composting. For vermicomposting it was established that both transformative processes were developed simultaneously from day 1 to 112. In the three systems, indicators of mineralization were total organic carbon, germination index, electrical conductivity, nitrates, the ratio of aliphatic to aromatic compounds and volume. For humification the indicators were total organic carbon, the ratio of aliphatic to aromatic compounds and the humification ratio. Conclusion: The assessment of the mineralization and humification processes provide information on the transformation rates, inputs, and the resulting quality of the products of the transformed OM. Research Highlights • Organic matter transformation encompasses two simultaneous processes; mineralization and humification. • During composting, dynamic changes in the chemical and structural properties of humus are not fully understood. • It has been claimed that mineralization and humification occur simultaneously, but it is the type and abundance of specific compounds that differentiate processes. • Intensity of the mineralization and humification during transformation developed simultaneously from 28 DT, however, the intensity of mineralization was greater, while in humification the increase was constant. • Increases in EC, GI and N-NO3 as indicators of mineralization in vemicomposting, semi-composting and composting. Increases in Humification ratio as indicators of humification in vemicomposting, semi-composting and composting.

Keywords

• Composting
• Semi-composting
• Vermicomposting
• Mineralization process
• Humification process