in the design of the plough boosted the productivity of the
Sumerian peasant. By 3000 BC, the original wooden ploughshare,
barely strong enough to scratch the ground without bending,
had given way in Sumer to a much sturdier bronze blade; some
ploughs were equipped with funnels that deposited seed as soon
as the ground was broken. Such tools proved so efficient that
a tenant farmer who paid as much as a half of his animal yield
in rent might still have sufficient left to support his family.