Study raises concerns about global crop projections

December 20, 2013, University of Nebraska-Lincoln

About 30 percent of the major global cereal crops – rice, wheat and corn – may have reached their maximum possible yields in farmers' fields, according to University of Nebraska-Lincoln research published this week in Nature Communications. These findings raise concerns about efforts to increase food production to meet growing global populations.

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 this research now suggests may not be possible.

Estimates of future and its ability to meet the dietary needs of a population expected to grow from 7 billion to 9 billion by 2050 have been based largely 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 – which 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 countries with greatest cereal production and provide evidence against a projected scenario of continued linear crop yield increase. 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 United States.

The Institute of Agriculture and Natural Resources scientists calculate that this decrease or stagnation in yield gain affects 33 percent of major rice-producing countries and 27 percent of major wheat-producing countries.

In China, for example, the increase in in wheat has remained constant, and rate of corn yield increase has decreased by 64 percent 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.

The authors report that 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, labour requirements, risks and environmental impacts may outweigh the benefits.

Explore further: Yield trends insufficient to double global crop production by 2050

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5 / 5 (2) Dec 21, 2013
NONSENSE! Sounds like this was written by always wrong, doomcaster Paul Ehrlich or one of his acolytes.

In the mid-90's I assisted a former Kansas county Ag agent/farmer to raise his yield of wheat from 60 bu/a, highest in the county, to 78 bu/a, a 30% increase, w/ one application of a natural material added to a normal fertilization spraying. Since then that technology has been advanced by many generations while the quantity used in the treatment has been reduced by very many orders of magnitude. And this is just scratching the surface. Flowering time, just root growth, just foliar growth, crop yield, all can be dramatically increased independently.
1 / 5 (1) Dec 21, 2013
In the mid-90's I assisted a former Kansas county Ag agent/farmer to raise his yield of wheat from 60 bu/a, highest in the county, to 78 bu/a, a 30%
That was a long time ago wasn't it?
Flowering time, just root growth, just foliar growth, crop yield, all can be dramatically increased independently
It is unrealistic to assume that plants can continue to be improved indefinitely. I would tend to agree with the experts in the article who have based their conclusions on the latest info from THIS century.

Pesticides are only 3-5 years ahead of pest adaptation, and optimism that new ones can be developed indefinitely is also unrealistic. This in conjunction with the loss of topsoil, fresh water, desertification, and other factors means that current population levels are unsustainable in many parts of the world unless vast new sources of energy can be found for desalination, automation, and greenhouse farming.

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