For non-subsistence farming, the amount of manure needed to replace the amount of nutrients being removed every year can result in too much of some things which

For non-subsistence farming, the amount of manure needed to replace the amount of nutrients being removed every year can result in too much of some things which can harm the ground. Growers have to be careful not to accidentally salt their ground with manure. Manure is also very heavy, and therefore expensive to transport, and that’s without going into restrictions that kick in when moving animal waste long distances. Pathogens, weeds and even pesticide residue are also a concern. The dairy I work with makes use of large digester tanks that help reduce these. Basically manure is great when you are close to a source (like a dairy), but you can’t put on too much or move it around too far without issues. So there is value in being able to economically break it up into it’s components.