The cover may be legumes (pueraria, centrosema, crotalaria, mucuna) or grasses.    From Wordnik.com.  [1.1. Forests] Reference

Chepil or chipil, crotalaria longirostrata: An important ingredient in Oaxacan cooking, probably because of its drought resistance, the tiny leaves are tucked into the famous tamales de chepil and their green bean-like flavor adds a delicious touch to white rice.    From Wordnik.com.  [A Culinary Guide to Mexican Herbs: Las Hierbas de Cocina] Reference

(showy crotalaria or rattlebox) and Indigo fera hirsute (hairy indigo) can reduce populations of most type of nematodes.    From Wordnik.com.  [Chapter 10] Reference