Castings are the worm's undigested residue, which includes soil, bacteria and plant residue.
In that process, plant residues and chlorophyll are separated from the sugarcane.
Decaying plant residues in the field are also a major loss factor.
The aims are generally to make use of plant residues from grape, olive (called pomaces) or pecan shells left after processing.
Instead of green manure the plant residues can be used as fuel.
Soil health is maintained by the selection of plants, mulching, and recycling of plant residues.
Some plant residue, however, must remain on the soil to avoid increased costs and emissions from nitrogen fertilizers.
Tegger searched out dried plant residues, but found nothing that even a Grass Giant would eat.
Other strategies, such as the use of weed-inhibiting plant residues, are also coming into wider use.
Soil can be easily eroded with no vegetative ground cover or plant residue.