In many traditional and organic farming practices , fields are rotated through various types of crops , which usually includes one consisting mainly or entirely of clover or buckwheat ( non-legume family Polygonaceae ) , which are often referred to as `` green manure '' .
In traditional farming practice , fields are rotated through various types of crops , which usually includes one consisting mainly or entirely of clover or buckwheat ( non-legume family Polygonaceae ) , which are often referred to as `` green manure '' .