Humus in soils is the largest terrestrial store of organic carbon.    Soils store around four times as much carbon as the entire vegetation of the earth or twice as much as the atmosphere. This is a huge potential which needs to be preserved.

It is very important to know the content on humus within the soil. Only if the farmer knows about the content he can decide how to treat the soil over the year. In arable soils, humus build-up is mainly determined by organic matter inputs via remaining plant residues and roots as well as organic fertilizers (compost, solid manure, slurry and fermentation residues).        Another promising method is the incorporation of carbonized plant residues (plant charcoal), which can be mixed with, for example, crop residues, manure, slurry, etc. In addition to the incorporation of organic substances 

the farmer can promote humus buildup through certain management practices, such as intercropping, undersowing, year-round revegetation, cultivating            

perennial crops or wide and varied crop rotations.

The content of humus has to be measured regularly.  The laboratory analysis of humus is the method of choice.

Humus...

  • promotes soil fertility and plant health
  • stores and provides nutrients for plants
  • increases soil pore volume and water holding capacity
  • improves water infiltration into the soil 

promotes a favorable soil structure and has filter and buffer function increases aggregate stability and reduces susceptibility to erosion.

https://stiftunglebensraum.org/wp-content/uploads/2019/06/Stiftung-Lebensraum_Einfu%CC%88hrung-Humuszertifikate-in-RLP.pdf

https://www.lufa-nord-west.de/index.cfm/article/1966.html