ABSTRACT
This chapter argues that the grid of flat-bottomed trenches, around 25 cm wide and deep, enclosing garden plots about 2—3 m square, which is the pattern of sweet-potato cultivation characteristic of the Wahgi valley, was originally developed in swampland agriculture. The revolutionary element which the sweet potato introduced into this situation was not simply that it was superior pig food, but that it was superior pig food that could be grown more productively over a wide range of soils and altitudes. Vicedom gives a long list of named categories within Hagen society, which fall into three broad and exclusive groups: those of big-men, ordinary men and men of low status. Vegetation histories show that forest cover in the agricultural zone was once complete. Its partial removal and replacement by grassland is generally accepted to be the product of clearance for cultivation maintained by fire. The conditions had matured therefore for intensive pig husbandry supported on an agricultural base.
