How does resource quality affect agricultural productivity worldwide?

A. Most differences in agricultural productivity, whether across countries or over time, can be attributed to differences in the quantity of conventional inputs used in agricultural production, such as land, labor, fertilizer, and machinery. But agricultural productivity also depends critically on the quality of inputs used, including land. Nevertheless, resource quality has received insufficient attention in the past because appropriate data have been scarce. Recent advances in data and analytical methods allow improved understanding of the ways in which land quality affects agricultural productivity, both directly and through other inputs and factors.  more