BLOOMINGTON – No-till can give growers a better return over a long time and a corn soybean rotation is the best for profitability.
Those were thoughts shared by Dr. Emerson Nafziger, a University of Illinois crop sciences expert, during an indoor field day hosted by the Illinois Fertilizer and Chemical Association.
Nafziger believes tillage tends to increase yields more when corn follows corn. The cost savings from no-till can be greater than the loss of yield, making this a profitable method in some soils. Keeping topsoil in place is critically important.
“That’s really why we talk about reducing tillage or increasing residue cover,” said Nafziger.
When following soybeans with any type of tillage, it does remove quite a bit of residue. Nafziger feels tillage has little effect on corn productivity as long as tillage provides a seed bed that allows good seed placement and a minimum of non-restricting soil conditions. In cold soils, tillage can increase the warming rate, improving stands and yield potential.
“Does more tillage actually help corn after corn? Our answer was not really,” explained Nafziger.
Doing strip till in continuous corn is not for the faint of heart – it can be problematic. You can do it late, but it may never be fit to do with corn after corn. Conventional tillage has not necessarily yielded more than strip till. Stripping looks promising and can save some costs if done right, according to Nafziger.
Trials at the Orr Center with corn following soy from 2008-2010 showed no-till yielding slightly less. Everything else was about the same. A tillage study in DeKalb showed little differences between chisel and no-till. There were some interesting results from a study in Brownstown with soy corn rotation in 2013 as they used a chisel and soil finisher in the fall.
“For some reason, using a finisher in the fall and in the spring again gave us 20 bushel of yield,” Nafziger noted.
When it comes to using starter fertilizer, Nafziger has not observed a big yield difference between those who use it and those who don’t. A continuous corn experiment at Monmouth in 2012 was one of the few times starter actually decreased yield.
Vertical tillage is alright if it helps make a better seed bed but otherwise may have a minimal effect. It is better than a disk for corn stalks to handle the residue.
“The response to tillage is less than many people expect,” Nafziger concluded.
Strip till with cover crops could be in our future but Nafziger expects the presence of cereal rye to impact some corn yields, taking nitrogen away. If nitrogen gets too low around the corn seedling, that could lead to serious problems.
As we are doing plenty of tillage in Illinois, there is little evidence the amount of soil disturbance has declined in the state.
“Tillage is a major cost item in production,” Nafziger acknowledged. “We could probably reduce tillage in half without affecting yield but this is hard to incentivize.”