A Humus

A large group of <a href="https://en.m.wiktionary.org/wiki/natural" title="natural" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; background: none rgb(255, 255, 255); color: rgb(107, 75, 161); hyphens: none;">natural</a> <a href="https://en.m.wiktionary.org/wiki/organic" title="organic" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; background: none rgb(255, 255, 255); color: rgb(107, 75, 161); hyphens: none;">organic</a> <a href="https://en.m.wiktionary.org/wiki/compound" title="compound" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; background: none rgb(255, 255, 255); color: rgb(107, 75, 161); hyphens: none;">compounds</a>, found in the <a href="https://en.m.wiktionary.org/wiki/soil" title="soil" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; background: none rgb(255, 255, 255); color: rgb(107, 75, 161); hyphens: none;">soil</a>, formed from the <a href="https://en.m.wiktionary.org/wiki/chemical" title="chemical" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; background: none rgb(255, 255, 255); color: rgb(107, 75, 161); hyphens: none;">chemical</a> and <a href="https://en.m.wiktionary.org/wiki/biological" title="biological" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; background: none rgb(255, 255, 255); color: rgb(107, 75, 161); hyphens: none;">biological</a> <a href="https://en.m.wiktionary.org/wiki/decomposition" title="decomposition" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; background: none rgb(255, 255, 255); color: rgb(107, 75, 161); hyphens: none;">decomposition</a> of <a href="https://en.m.wiktionary.org/wiki/plant" title="plant" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; background: none rgb(255, 255, 255); color: rgb(107, 75, 161); hyphens: none;">plant</a> and <a href="https://en.m.wiktionary.org/wiki/animal" title="animal" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; background: none rgb(255, 255, 255); color: rgb(107, 75, 161); hyphens: none;">animal</a> <a href="https://en.m.wiktionary.org/wiki/residue" title="residue" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; background: none rgb(255, 255, 255); color: rgb(107, 75, 161); hyphens: none;">residues</a> and from the <a href="https://en.m.wiktionary.org/wiki/synthetic" title="synthetic" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; background: none rgb(255, 255, 255); color: rgb(107, 75, 161); hyphens: none;">synthetic</a> <a href="https://en.m.wiktionary.org/wiki/activity" title="activity" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; background: none rgb(255, 255, 255); color: rgb(107, 75, 161); hyphens: none;">activity</a> of <a href="https://en.m.wiktionary.org/wiki/microorganism" title="microorganism" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; background: none rgb(255, 255, 255); color: rgb(107, 75, 161); hyphens: none;">microorganisms</a>