For decades, all of the major row crops have seen their yields inch ever-higher. But the University of Nebraska-Lincoln says several major crops might see a plateau in yield potential. About 30% of the major global cereal crops, including rice, wheat and corn, may have reached maximum possible yields, the university released in a statement by Kenneth Cassman and Patricio Grassini (agronomy/horticulture department) and Kent Eskridge (statistics department).
"Yields of these crops have recently decreased or plateaued," the researchers say. "Future projections that would ensure global food security are typically based on a constant increase in yield, a trend that this research now suggests may not be possible."
UNL agronomy and statistics scientists studied past yield trends in countries that produce the greatest amount of cereal crops. Their data suggest 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 U.S. The Institute of Agriculture and Natural Resources scientists say this stagnation in yield gain is affecting 33% of major rice-producing countries and 27% of the world’s major wheat-producing countries.
In China, for example, the increase in crop yields in wheat has remained constant, but the rate of corn yield increases has diminished 64% relative to a decade ago, despite a large investment in ag research, education and infrastructure during that time period.
"This suggests that return on these investments is steadily declining in terms of impact on raising crop yields," the researchers say. "Sustaining further yield gain likely would require fine-tuning of many different factors in the production of crops. But this is often difficult to achieve in farmers’ fields, and the associated marginal costs, labor requirements, risks and environmental impacts may outweigh the benefits."
The researchers findings were published in the journal Nature Communications.