The security and productivity of farms

Nick Szabo has a superb post about the interaction between historical agricultural productivity and security.   Most obviously, security increases the incentive to invest so agricultural productivity will increase with security.  But what determines security?  Geographic factors are one possibility:

...two large islands which have been largely or entirely protected from invasion for hundreds of years, Japan and Britain, also had among the highest agricultural productivities per acre during that period as well as the greatest cultivation of even marginal arable lands.... Contrariwise, this theory predicts agricultural productivity will be lowest in unprotected continental regions. Indeed, interior continental regions easily reached by horse tended to be given over to much less productive nomadic grazing. Security constraints were probably what prevented any sort of crop from being grown.

Security issues influence and can be influenced by a wide variety of other choices and institutions.  Some crops will recover from a razing quicker than others, for example, so crop choice will be influenced by security.  Primogeniture may have been an optimal institution to maintain economies of scale in land defense, as Adam Smith first discussed.

Read the whole thing there is a dissertation or two here.