About 30% of the major global cereal crops, including corn, wheat and rice, might have reached their maximum possible yields in farmers’ fields, according to University of Nebraska–Lincoln (UNL) research published recently in Nature Communications. These findings raise concerns about efforts to increase food production to meet growing global populations.
Estimates of future global food production and its ability to meet the dietary needs of a population expected to grow from 7 billion to 9 billion by 2050 have been largely based on projections of historical trends. Past trends have, however, been dominated by the rapid adoption of new technologies, some of which were one-time innovations that allowed for an increase in crop production.
As a result, projections of future yields have been optimistic—perhaps too much so, indicates the findings of UNL scientists Kenneth Cassman and Patricio Grassini of the agronomy and horticulture department and Kent Eskridge of the statistics department.
They studied past yield trends in the countries with the greatest cereal production and provided evidence against a projected scenario of continued linear crop yield increase. Their data 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 U.S.
The Institute of Agriculture and Natural Resources scientists say this decrease or stagnation in yield gain affects 33% of major rice-producing countries and 27% of major wheat-producing countries.
The authors report that sustaining further yield gain would likely require fine-tuning many different factors in crop production. But, this is often difficult to achieve in farmers’ fields, and the associated marginal costs, labor requirements, risks and environmental impacts might outweigh the benefits.