Corn Pest Beat: Do what you can to mitigate the effects of wet spots by adjusting agronomic practices.
Dec 30, 2019
Our 2019 yield maps showed losses due to wet soil that extended far beyond the wet spots. This was mostly on rented land where the landowner won’t invest in tile. Those fields dry out slower in the spring and get hurt worse by big rains. Because tile isn’t an option, what can we do agronomically to set ourselves up for more profitable yields?
The panel of Indiana certified crop advisers answering this question includes Steve Gauck, Beck’s sales agronomist, Greensburg; Andy Like, Syngenta, Vincennes; and Jeff Nagel, Ceres Solutions agronomist, Lafayette.
Gauck: Let’s first look at why those areas of the field are wet. Is it a natural low spot that holds water? If so, is there a way to create better surface drainage by leveling or sloping that area? Another big concern in wet areas is soil compaction. Since these spots are always wet, through the years we create soil compaction layers throughout the soil profile. Deep tillage or ripping can help move the water into the profile more quickly. If you are no-tilling, using cover crops with deep taproots can work like tillage and help move water. I would also look at your soil test. If those areas are low on pH or calcium, lime or gypsum applications can help improve water infiltration.
Like: I would start by selecting a corn hybrid that has good emergence scores to help your chances of getting the corn out of the ground if you must plant wet or you get a heavy rainfall event before emergence. Secondly, selecting a hybrid that can handle wet soils will help with yield and standabilty. Lastly, armed with the knowledge that these soils will likely be saturated at some point during the season, I would make a sidedress nitrogen application that includes a nitrification inhibitor, so you can minimize nitrogen losses.
Nagel: Nothing will replace the positive effect of tile in those situations. Fields like you describe can yield very well in a drier growing season, but those big rain events can drop field averages in a hurry. Given that you must manage what you have, here are four considerations:
1. Evaluate tillage systems. It might not be feasible, but strip tillage might have an advantage. You’re not going to eliminate the ponds, but a slightly elevated seedbed may prove beneficial in those fringe areas. Roots need air to breathe, and the benefit of lower residue and elevation will allow for more rapid field drying in the seed zone.
2. Check for soil compaction. If you find compacted layers, the use of a ripper might be helpful and improve water infiltration.
3. Consider cover crops. Grass cover crops allowed to grow in the spring can help remove water through evapotranspiration. This is a high-management system, and termination too early can lead to even wetter soils. This is an option only if you have experience with cover crops or are willing to experiment and adjust termination based on spring conditions.
4. Select hybrids carefully. Ask your seed dealer if they have any corn hybrids that tolerate wet soils or have a lesser yield penalty with wetter soils.