§Autumn sowing of wheat or rye, harvested following
summer.
§A year
fallow.
§Nitrogen fixing by soil bacteria.
§Manure from
pasturing.
Three-course rotation in wide use by
ninth century.
Four seasons and seasonal labors.
From Bartholomaeus
Anglicus (Bartholomew the Englishman), On the Properties of Things. France,
Le Mans 15th Century. Bibliothèque Nationale de France.
