the manor: design as agricultural self sufficiency

medieval farmers were highly adept. they used the three-field system of crop rotation (actually the best developed system up to that time). 

why?

crop rotation means planting a series of different types of crops in the same area across a sequence of growing seasons. the rotation reduces reliance on one set of nutrients, pest and weed pressure, and the probability of developing resistant pests and weeds.

growing the same crop in the same place for many years in a row, known as monocropping, gradually depletes the soil of nutrients and selects for a highly competitive pest and weed community.

so, wheat or rye was planted in one field; oats, barley, peas, lentils or broad beans were planted in the second field. the third field was left fallow. each year the crops were rotated to leave one field fallow.  

the system also ensured that the same crop was not grown in the same field two years running.

medieval farmers did what they could to increase the fertility of the land. they used "marl" (a mixture of clay and carbonate of lime) and seaweed. in addition they used the best fertiliser: animal dung.