soil biota is the generic term used to describe the population of organisms living in soil. Broadly speaking, these organisms can be divided into the ‘reducers’, such as earthworms, slugs and snails, beetles and their larvae, mites and springtails, Protozoa, and nematodes, which feed on leaf litter and animal excreta to break it down into smaller fragments (without achieving much chemical decomposition), and the ‘decomposers’, which are much smaller organisms that colonize these organic fragments and gradually convert them into humus (see carbon and organic matter). The decomposers, comprising Archaea, bacteria, actinomycetes, and fungi, are commonly called microorganisms and the microbial biomass is measured by their collective weight. An active and diverse microbial biomass, interacting with the reducers, is important for organic matter decomposition and nutrient turnover in soil, which is a prerequisite for good soil health. This applies equally well to conventional viticulture as to organic and biodynamic viticulture. See also mycorrhiza, microbial terroir, and biochar.