Agricultural output arises from either bringing more resources
into production or by raising the productivity of those resources.
Productivity of the sum of land, labor, capital and material
resources is known as "total factor productivity" or TFP.
Between 1961 and 2009, about 60 percent of the tripling in global
agricultural output was due to increases in input use, implying
that improvements in TFP accounted for the other 40 percent. TFP's
share of output growth, however, grew over time, and by the most
recent decade (2001-09), TFP accounted for three-fourths of the
growth in global agricultural production. The rate of expansion in
use of natural resources (land and water) has slowed slightly over
time while the rate of growth in input intensification has fallen
sharply. As such, the source of increase in agricultural yield has
shifted markedly from input intensification to improvement in TFP.
This chart appears in "New Evidence Points to Robust But
Uneven Productivity Growth in Global Agriculture" in the
September 2012 issue of ERS's Amber