In what type of bioregion is desertification most likely to occur?

Desertification is most likely to occur in grasslands.

Desertification is the process by which fertile land is changed into desert due to certain conditions such as deforestation and drought which makes the land unsuitable for any plant growth for food production.

Grasslands are regions of lands dominated by grasses with or without any sparse tree. Grasslands occupy most of the eco-regions of the earth and they contain several grass species such as sedge, rush, and legumes such as clover and other herbs.