The subject of this paper is the interaction between the basic factors of agriculture - climate, soil, topography and more institutional arrangements such as rotation systems, manorial structures and type of tenure - and the lords' wishes to shape the economic development of their estates. Demesne farming in 13th century England was, according to M.M. Postan, characterized by rising production, technical improvement, the investment of capital and a greater emphasis on production for sale and the spread of more or less capitalistic agriculture. To Postan the question of agricultural productivity was closely linked to his neo-Malthusian theory, but recent research, influenced first of all by Bruce Campbell, has stressed the need for seeing medieval productivity in a much wider perspective. One of the most striking features in this transformation was the attempt to raise the yield through the introduction of new and more efficient farming practices, e.g. intensified manuring, improvement of the seed, a higher stocking ratio, changes from two- to three-field systems and the growing use of legumes. The intense economic activity of the 13th century, most notable through the buoyant price level of corn, made the idea of fixed returns inherited from the 12th century lessee (firmarius) increasingly unsatisfactory - a shift in attitude presumably related to the making of Walter of Henley Husbandry and Seneschaucy and their description of a more rational approach towards farming and accounting.

On the other hand we find ample proof of the existence of manors, where the introduction of more efficient cropping arrangements apparently was motivated, not by the want of profit, but solely to secure economic stability. The predominance of production for consumption on the Winchester manors must, of course, first of all attribute to geographic isolation and the low productivity of the soil, but the marked contrast between the lack of market-oriented husbandry on the estates of Saint Swithuns Priory and the immense corn sales from the manor of Sevenhampton indicates that account must also be taken of such human variables as efficiency of management and its capability of moderating environmental disadvantages.