Table 3.

Variable definitions and sources

Term and applicable year	Definition	Source
Acreage, 1990	Thousands of hectares cultivated for a particular crop.	FAOSTAT. Accessed at: http://faostat.fao.org/site/567/default.aspx.
Cereal imports per capita, 1990.	Tons of cereals imported in 1990/population of the nation.	Earthtrends. Accessed at: http://earthtrends.wri.org/.
Conservation set-aside programs, 1990	A binary variable; 1, program; 0, no program.	A list of the countries with programs and the sources for this information are provided in section D of the SI Appendix in supporting information.
Gross domestic product per capita, 1990	In U.S. dollars.	Penn World Tables. Accessed at: http://pwt.econ.upenn.edu/.
Land sparing, 1990–2005	ln (2005 Yield/2005 Area Cultivated) − ln (1990 Yield/ 1990 Area Cultivated).
Irrigated land, 1990	Proportion of national land area that was irrigated in 1990. Irrigated acreage in hectares/national land area in hectares.	Earthtrends. Accessed at http://earthtrends.wri.org/
Production, 1990	In tons.	FAOSTAT. Accessed at: http://faostat.fao.org/site/567/default.aspx
Proportion of the national population that was economically active in agriculture, 1990	Given as percentage.	FAOSTAT. Accessed at: http://faostat.fao.org/site/567/default.aspx.
Proportion of national land area under cultivation for this crop, 1990	Hectares cultivated in 1990/national land area.	FAOSTAT. Accessed at: http://faostat.fao.org/site/567/default.aspx.
Regional dummy variables	1, in region; 0, outside of region.	For the geographical boundaries of the regions, see section A of the SI Appendix.
Yield, 1990	In kg/ha.	FAOSTAT. Accessed at: http://faostat.fao.org/site/567/default.aspx.