LINCOLN, Neb.—About 30% of the major global cereal crops—rice, wheat and corn—may have reached their maximum possible yields in farmers' fields, according to new research published in the journal Nature Communications.
Yields of these crops have recently decreased or plateaued. Future projections that would ensure global food security are typically based on a constant increase in yield, a trend that research now suggests may not be possible. As a result, projections of future yields have been optimistic—perhaps too much so.
University of Nebraska-Lincoln researchers studied past yield trends in countries with greatest cereal production to provide evidence against a projected scenario of continued linear crop yield increase. Estimates of future global food production have been based largely on projections of historical trends. Past trends, however, have been dominated by the rapid adoption of new technologies—some of which were one-time innovations—which allowed for an increase in crop production.
The research suggests that the rate of yield gain has recently decreased or stopped for one or more of the major cereals in many of the most intensively cropped areas of the world, including eastern Asia, Europe and the United States.
In China, for example, the increase in crop yields in wheat has remained constant, and rate of corn yield increase has decreased by 64% for the period 2010-2011 relative to the years 2002-2003 despite a large increase in investment in agricultural research and development, education and infrastructure for both crops. This suggests that return on these investments is steadily declining in terms of impact on raising crop yields.