Renewable Farming

How much carbon does a corn crop need to extract from the environment?

One bit of doctrine brushed aside in the Church of Climate Change is that epochs of high carbon dioxide have generally been benign for civilizations, with abundant food supplies and even wine grapes growing in northern England.

These warmer climates typically preceded, rather than followed, upswings in carbon dioxide content of the atmosphere. 

The point is, crops have to extract carbon from someplace, and high carbon content in the atmosphere is helpful for crop production.  Typically they get it from the atmosphere, plus the CO2 exuded from the aerobic respiration of microbes and the other organisms living in the soil. 

The photo below, taken Friday a few miles south of Cedar Falls, IA, dramatizes how much carbon is required for a corn crop. The square bales in this stack are just one of several stacks in the area. The stack contains about 1,500 bales, apparently taken from a field of about 140 acres. A 210-bu. corn crop generates as much above-ground corn stover, by weight, as it generates in grain. So an acre of 210-bu. corn would produce roughly 8 tons of dry leaves and stalks.  

Carbon stash: cornstalk bales in northeast Iowa

Mature cornstalks and leaves are about 45% carbon. So the stover from one acre represent 3.6 tons of carbon.  Generally, roots equal the biomass of stalks. So there’s another 3.6 tons of carbon underground which must also come from the same atmospheric sources — under the canopy or the atmosphere at large. Corn kernels are also about 45% carbon, which adds another 3.6 tons per acre. Total carbon “sequestered” in that 210-bu. crop: almost 11 tons per acre.

James Hansen, retired NASA scientist, says that the Paris “conference” is all hat, no cattle… what’s really needed, he urges, is a tax of $15 per ton of carbon emitted as carbon dioxide. That would curb burning of “fossil” fuels, he says. Thus, shouldn’t farmers get a $15 per ton benefit for sequestering that much carbon? At a conservative 10 tons per acre, that would be $150 per acre.

Climate change acolytes stress that the more carbon is extracted from the atmosphere, the less will be used by growing plants. Put another way, an atmosphere with less CO2 means less carbon nutrition will be available to growing crops… therefore less food production.  That’s one part the warmists have right.