The effects of phenolic compounds on soil properties

Abstract

Phenolic compounds are some of the most widespread molecules among plant secondary metabolites that play an important role in ecological processes in many plant communities through their effects on soil ecology. They are leached out from green foliage, decomposing litter, as well as by root exudates and thus reach the soil underneath the canopy. In terms of their abundance and primary productivity, the dominant species in plant communities have a great significance as the main source of phenolics, and therefore significant effect on plant-litter-soil interactions. Decomposition of plant litter as a crucial process in nutrient cycling in all terrestrial ecosystems is affected by phenolic compounds through effects on the composition and activity of the decomposer (soil microorganisms), on the rate of organic matter decomposition, and on soil C and N cycling. Phenolics can alter N availability by complexation with proteins from litter or with extracellular enzymes from microorganisms. The resulting decrease in the inorganic N availability for plant uptake may potentially affect plant growth. Therefore, soil fertility is influenced by phenolic compounds from plant or microbial sources not only because they are important precursors of soil stable humic substances, but also for their effects on soil nutrient dynamics (N, P, K, Mn, Fe, Cu, etc.), pH, ion-uptake, soil aggregation, etc. In addition, interaction between phenolics and different heavy metals through complexation and reduction reaction, affects their mobility and toxicity in soil. All above mentioned effects can influence natural regeneration of ecosystems.