Crop yields to rise even with climate change

Benefits of higher carbon dioxide levels will offset impact of global warming, an American speaker says at Grain World

Some people peer closely at crop statistics.

Others get down on their hands and knees to figure out exactly how many cobs and kernels of corn or heads and kernels of wheat are in a square yard of farmland.

Kurt Ahrens does both, and the fanatical crop tour participant gave good news to Grain World’s packed hall Nov. 15.

He expects crop yields and production to keep steaming ahead at the same pace regardless of climate change.

“I couldn’t come up with a reason why biology’s not going to continue to improve into 2050 at the same rate that it’s improved 1970 to present,” said Ahrens, who operates the corn and wheat focused analytical firm Grainbot.

“I couldn’t come up with a reason why farm management won’t continue to improve at the same rate it has since 1970.”

Those factors aren’t negated by climate change, Ahrens said, because commonly used models that suggest yields will plunge as a result of climate change don’t take into account carbon dioxide fertilization.

He said the beneficial impact of heightened carbon dioxide levels in the air will almost entirely offset the heat stress from climate change. In fact, the overall impact should be slightly positive.

When he adds up the negligible impact of climate change with continuing improvement of crop yield potential and improving farm management, he comes out with a prediction of world corn yields increasing 39 percent by 2050, wheat increasing by about 33 percent and soybeans increasing by 31 percent.

Many are skeptical that yields can keep increasing at the heady pace of recent decades, but Ahrens doesn’t see why they can’t. No “biological wall” appears to have been discovered, he argued, and decades of progress have not revealed insurmountable barriers.

For instance, the average broiler chicken weighed less than three pounds in the 1930s and is more than six lb. now. Why can’t chickens keep getting bigger?

The same goes for farm management improvements. Farmers are much more efficient and skilled than in the past, are much more quickly embracing and developing innovations and new practices and are likely to get even more aggressive in coming decades.

If the average bag of corn seed has 600 bushels per acre of yield potential, and farmers are only on average getting a bit more than one-quarter of that potential, there’s no reason to think future gains can’t keep production rising.

Climate change might be bringing more volatile weather, but Ahrens also doesn’t think that’s a crippling constriction.

This year was a good example. Wheat crops in both Kansas and North Dakota were hit by brutal weather conditions. Kansas faced drought and a killing frost, while North Dakota faced the worst drought in memory.

The result?

“It turned out to be one of the best crops that’s we’ve ever had (in Kansas),” said Ahrens.

The North Dakota crop turned out much better than expected.

Others have also noticed Ahrens’ observations about the toughness of contemporary crops to negative circumstances. At Grain World, recent increases in soybean yield gains were posited as a change in growth trend to the upside.

For Ahrens, who specializes in wheat and corn, nothing he sees suggests that farmers and crops won’t be able to face weather challenges while continually boosting their average yields.

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