Agriculture was extremely crude. But eight or nine bushels of wheat or rye were expected from an acre, where now in England the average is thirty. The plough regularly required eight draught animals, usually oxen, in breaking up the ground, though lighter ploughs were used in subsequent cultivation. The breed of all farm animals was small, carts were few and cumbrous, the harvesting of grain was done with a sickle, and the mowing of grass with a short, straight scythe. The distance of the outlying parts of the fields from the farm buildings of the village added its share to the laboriousness of agricultural life. [Illustration: Modern Ploughing with Six Oxen in Sussex. (Hudson, W. H.: _Nature in Downland_. Published by Longmans, Green & Co.)] [Illustration: Open Fields of Hayford Bridge, Oxfordshire, 1607. (Facsimile map published by the University of Oxford.)] The variety of food crops raised was small. Potatoes were of course unknown, and other root crops and fresh vegetables apparently were little cultivated. Wheat and rye of several varieties were raised as bread-stuff, barley and some other grains for the brewing of beer. Field peas and beans were raised, sometimes for food, but generally as forage for cattle. The main supply of winter forage for the farm animals had, however, to be secured in the form of hay, and for this reliance was placed entirely on the natural meadows, as no clover or grasses which could be artificially raised on dry ground were yet known. Meadow land was constantly estimated at twice the value of arable ground or more. To obtain a sufficient support for the oxen, horses, and breeding animals through the winter required, therefore, a constant struggle. Owing to this difficulty animals that were to be used for food purposes were regularly killed in the fall and salted down. Much of the unhealthiness of medieval life is no doubt attributable to the use of salt meat as so large a part of what was at best a very monotonous diet.