Grantham: > 7. We now have two excellent studies of large-scale > farming around Paris (J.-M. Moriceu, Les fermiers de l'Ile > de France, and J-M. Moricea and G. Postel-Vinay, Ferme, > entreprise, famille), which reveal the extent to which a > growing market opportunity could induce productivity growth > among the farms that served it. The sources of this growth > are multiple: rearrangement of plots--often by sub- letting > and exchanges--in order to reduce the time required to > plough and sow; increased investment in carts and weagons; > new barns and hangars; increased sales of by-products like > straw to urban and noble stables; multiplied ploughing, and > sowing more legumes. All of these are associated with the > agricultural revolution. What is interesting is that the > same responses have been detected in medieval accounts on > farms subject to the same kind of market opportunity. The > time series indicate that when these opportunities > contracted, as they did in northern Europe after 1300 and > around Paris for about 80 years after 1660, productivity > tended to fall off. Here G picks up some of the sources of growth that are "associated with the agricultural revolution", to argue that those sources were always there, ready to be used depending on market opportunities: if "these opportunities contracted, as they did in northern Europe after 1300 and around Paris for about 80 years after 1660, productivity tended to fall off" Again, I think Grantham does not quite understand the nature of agrarian change in pre-industrial Europe (though I would hesitate saying this to him in the open as he might very well put me in my place!). Yes, early on in the medieval period (perhaps as far back as the 9th century in some estates) we can already detect a triennial system of rotation in which cereals are sown along with leguminous plants. But we must not underestimate the fact that the variety and quantity of these plants increases with time, that farmers gradually learn how to cultivate new fodder crops, and how to alternate different crops in new rotations. Even if there is evidence that "clover was being sown in the Rhineland" by the 13th century (point 2), it was only in the seventeenth century, that it was used on a large scale *alongside the cultivation of turnips* - that is, my point is that it is not simply the cultivation of this or that fodder but how many types of such crops were being sown and in what system of rotation.