Enzyme activities and metabolic profiles of soil microorganisms at KILN sites in Quercus spp. temperate forests of central Mexico

Abstract

Temperate forest dominated by Quercus L. spp. cover large parts of central Mexico and rural communities depend on these forests for wood and charcoal. The impact of charcoal production on enzymatic and metabolic profiles of soil microorganisms in the 0–15 cm layer were investigated during the dry and rainy season. A KILN site, used for charcoal production, is prepared by clearing all vegetation, removing litter and soil from the surrounding area. The wood is piled up in the centre of the KILN site and covered with litter and soil. Incomplete combustion with a minimum of flame production is maintained for 12 days. The charcoal production had a negative effect on the functional diversity and enzymatic microbial activity in soil. Community level physiological profiles (CLPP) analyses showed a lower average well color development, substrate richness, and functional diversity in soil at the KILN sites compared to the undisturbed soil. Cluster analysis dendrograms and canonical discriminant analysis of CLPP indicated that substrate utilization at the KILN sites was different from undisturbed forest soil. The activity of six enzymes, i.e. CM-cellulase, β-glucosidase, N-acetyl-β- d-glucosaminidase, nitrate reductase, urease and proteinase, decreased from 44% to 90% at the KILN sites compared to the undisturbed forest soil. It was found that charcoal production at a KILN site showed lower functional diversity and enzymatic microbial activity than in the surrounding forest soil as a result of loss of litter and organic matter and changes in microclimatic conditions.