Why wait 2000 years to adopt a natural and more efficient way to grow food?

“The recycling of organic wastes was perfected over centuries in Europe. But their Nitrogen content is only 0.5% and the heavy labor of collecting and distributing up to 40 tons of wastes per acres of city execra resulted in an overall loss of 60% of energy loss per cultivated acre.

Green manuring was used by ancient Greek and Romans and in East Asia. Nitrogen fixing leguminous can replenish the soil over 4 months when cultivated in alternance with crops.

But it was only between 1750 1880 that the generalization of rotations of legume over crops enabled high yelds, intensive agricultural system and a greater variety of diet.”

Vaclav Smil – Energy and Civilization