Optimum level of humus which is a specific fixed value for each type of soils is therefore realized. An energy humus index is proposed, which may indicate preferred usage of organics as fertilizer or renewable energy source.doi:10.1002/cite.201100247Dr. Konrad SoyezDr. Jürgen Reinhold...
doi:10.1002/jpln.19430320104Ruschmann, G.Themlitz, R.Pozdena, L.Bartram, H.WILEY‐VCH VerlagBodenkunde Und Pflanzenernhrung