Farmers need to clean fields up before spring, says expert
Farmers may need to get in the fields before spring to clean up crop residue buildup caused by this winter's intense rainfall and flooding, said a Purdue University expert.
With all of the rain this year, farmer's need to be aware of what this could mean for their soil nutrition and the negative effects that crop residue can have on a crop yield, said Tony Vyn, Purdue professor and cropping systems agronomist.
"The good news is that no-till or strip-till fields that had the residue cover lost less soil during the intensive rain and subsequent flooding," Vyn said. "Soil erosion losses and, therefore, long-term crop yield losses and nutrient losses to surface water, were worst in fields that had no protective residue cover."
Even with no-till or strip-till farming steps still should be taken to clean up fields.
"The bad news is that much of the residue that was not firmly anchored accumulated in ditches and around drain inlets," Vyn said. "Those residue piles cannot be ignored since they will reduce both optimum drainage and crop yield in 2008."
If left alone, these residues will impede surface drainage in subsequent high rainfall events, Vyn said. Most of the residue piles on or next to farm fields are so thick that the normal decomposition process of corn stalks and others will not work fast enough to avoid planting problems for this spring.
Thick residue can impede crop emergence. But even when corn and soybean plants manage to emerge through thick residue, the crops suffer by growing slower and by having thinner stems, which makes the crop yields lower, Vyn said.
"Ideally, residue piles need to be spread back out again using tillage tools, backhoes or tractor-mounted blades," Vyn said. "The best time to do this is when the soil is frozen."
Farmers should try to spread the residue out so that it is no more than two inches thick, he said. Corn and soybean planters equipped with tined row cleaners will then be effective in removing the residue from the crop row area this spring.
Burning of residue piles is another option, but can be difficult when the piles have built up in wet low spots of ditches and fields, Vyn said. Even if burning was the chosen option, it is important to first move the residue piles well away from plastic drain risers and hazardous locations.
"Burying the old crop residue via intensive tillage operations places most soils at too much risk of soil loss," he said. "Farmers cannot always see sheet erosion losses, and the sediments will often make it all the way to the rivers instead of building up around drain inlets."
While surface residue loss is more noticeable, the good news is that it has little consequence on the long-term sustainability of the fields that it came from, Vyn said.
The negative consequences of residue on crop yield are more of a problem in cool, wet springs, he said.