Argonne researchers find clues to how much corn stover required for healthy soil

In Illinois, scientists at the U.S. Department of Energy’s (DOE) Argonne National Laboratory are conducting pivotal research that will help keep soil healthy now and into the future. Scientists have long known that corn residue or stover — meaning the aboveground portions of the corn plant remaining after harvest — plays a critical role in soil health. Corn stover is mostly left on the field either in its entirety or in a lesser amount, depending on the farmer’s practice and soil type.

Corn stover is a promising biofuel feedstock. The key question is whether corn stover removal may affect soil organic carbon (SOC) and soil health.

Researchers, aware of the problem, have been studying it for years, but their findings have varied. While excessive stover removal is not a preferred practice, leaving too much corn stover can also cause problems like harbor diseases, tie up nitrogen in the soil, and impede soil warm-up which is important for planting in the spring. This is why it is beneficial to leave some corn stover on the fields but also to collect the excess.

Scientists at Argonne, who also had been examining the issue, led a pioneering collaboration to screen 3,380 papers published between 1990 and 2018 to quantify the overall response of soil carbon to stover removal and to identify key drivers that can help with maintaining soil health.

They collected and analyzed 409 data points from 74 stover harvest experiments sites around the world.

Teamed up with researchers from United States Department of Agriculture and universities, they came to important conclusions that could help farmers manage their fields in a sustainable way.