Tuesday 19 March 2013

Removing corn stover? Keep your soil intact reports on a study which illustrates the soil benefits associated with leaving unwanted plant material and crop residues, in this case maize stover, on the soil after harvest.

The article reports that a growing amount of corn stover (leaves and stalks) is removed from fields during or after harvest. But the removal of that critical crop residue could be causing harm to your fields' future viability, the results of a new study show.

The potential danger is 2-fold; first, there's the potential increase in greenhouse gas emissions caused by the release of nutrients and accompanying carbon while the stalks are being removed from the field. Then, there's the loss of soil structures caused by another tillage pass in the field.

"For a given crop rotation and tillage system, as we simulated an increase in the rate of stover removal we found an increase in loss of sediment from crop fields, an increase in greenhouse gas flux to the atmosphere and a reduction in nitrate and total phosphorus delivered to waterways," says Purdue University ag economist Ben Gramig. "While optimizing production to maximize stover harvest at the lowest possible cost may lead to a reduction in nutrients delivered to rivers and streams, this comes at the expense of increased soil erosion and greenhouse gas emissions."

As much as 3.5 tons of greenhouse gas and 1.1 ton of soil sediment per acre is lost from a field under conventional tillage when just over half the stover is removed, a process that nets around 2.7 tons of of the cellulosic ethanol feedstock, according to Gramig's research.

Read more here.