What are clay seed balls?

The Japanese farmer Masanobu Fukuoka sowed without digging: he rolled a mix of seeds into balls of clay and scattered them. Clay hides the seeds from birds and ants, then softens in the rain so the seedlings start with a little water of their own. How: 1 part seeds (clover, lucerne, phacelia, wildflowers, radish, local trees and shrubs), 3–5 parts clay powder and a little compost; add water until it handles like modelling clay, roll walnut-sized balls, dry them in the shade. Scatter them before rains in autumn or early spring, on waste ground, a slope, along a future hedge. Not everything comes up, and that's fine.