Washington, Dec 19 (IANS) A wilting Green Revolution is adversely affecting grain output in China and India, warn US and Canadian scientists, adding that output of crops meant to feed animals or provide car fuel seems to be getting priority.
The scientists found that the output of wheat and rice, which supply roughly half of the world's dietary calories - is declining across a higher percentage of cropland worldwide than those of corn and soybean, which are used largely to feed cattle for slaughter or biofuel.
Reserchers from University of Minnesota's Institute on the Environment (IonE) and McGill University led by IonE's Deepak Ray, developed geographically detailed maps of annual crop harvested areas and yields of maize (corn), rice, wheat and soybean from 1961 to 2008, the journal Nature Communications reports.
It found that although virtually all regions showed a yield increase sometime during that period, in 24 to 39 percent of the harvested areas (depending on the crop) yield plateaued or outright declined in recent years, according to an IonE statement.
"This study clearly delineates areas where yields for important food crops are stagnating, declining, or never improved, as well areas where yields are still rapidly improving," Ray says.
"As a result, it both sounds the alert for where we must shift our course if we are to feed a growing population in the decades to come, and points to positive examples to emulate."
"This finding is particularly troubling because it suggests that we have preferentially focused our crop improvement efforts on feeding animals and cars, as we have largely ignored investment in wheat and rice, crops that feed people and are the basis of food security in much of the world," said study co-author and IonE director Jonathan Foley, professor.
"How can we meet the growing needs of feeding people in the future if one-third of our cropland areas, in our most important crops, are not improving in yield any more," asked Foley.
The paper suggests two actions based on its findings: First, it recommends working to maintain the positive trajectory for the 61 to 76 percent of croplands where yield is still climbing. Second, it encourages crop-producing regions around the world to look at their yield trends and those of others to identify what is working and what might be improved.