Population pressure, intensification of agriculture, and rural-urban migration.

"In this paper I provide an analytical basis for why labor absorption [in agriculture] may improve with higher population density. My argument is in two parts. First, analysing agriculture in isolation, I use the Boserup insight to show that higher population density is associated with more intensive techniques of land use. Second, using a two-sector model, I show that the rate of labor absorption (defined as the rate of natural population growth minus the rate of rural-urban migration) increases with the intensity of land use." Cross-sectional data for Iran are used to illustrate the model.