WATERLOO, NY — The Northeast has experienced its share of extreme weather in recent years, with excessive rainfall in 2015 and drought last year. As with any crop, growing good corn requires farmers to plan for less-than-ideal weather. Quirine Ketterings, nutrient management Spear Program at Cornell University and Don Specker, DuPont Pioneer, North Atlantic Commercial Unit, recently presented “Corn Nitrogen Management in Extreme Weather Years” at the annual Corn Congress.
“Excessive water really effects our yields,” Ketterings said to begin her portion of the presentation.
She defined production success as yield levels, milk production, returns on investment, ability to deal with weather extremes, protection of soil resources against erosion and production decline, use of resources to build and maintain fertility and reduced environmental footprint.
A field’s biological buffer capacity (BBC) represents its ability to counter weather extremes.
Ketterings encouraged farmers to identify the fields that yield the most and are stable regardless of weather, identify why the fields perform so well in unfavorable weather, and analyze if those traits can be replicated in other fields to boost their potential for yield, too.
She explained that BBC factors include the timing and amount of rainfall, drainage, and soil fertility.
Ketterings presented findings from six on-farm trials from 2014 to 2016. The farms using conventional tilling saw no advantage in yield over farms practicing no-till.
“I’m not saying everyone should do this,” Ketterings said. “Knowing yield is key.”
Ketterings said managing nitrogen in the soil is critical for fertility when growing corn. She listed as tools for nitrogen management soil nitrate, Illinois Soil Nitrogen Test, crop sensors for variable rate nitrogen, and corn stalk nitrate test.
The standard for years has been the pre-sidedress nitrate test. Ketterings said it is a difficult test to use in extreme weather years. She likes the Illinois Soil Nitrogen test, which is valid for three years and may be conducted anytime except within five weeks after manure application.
Active crop sensors provide another means of nitrogen monitoring.
“It lets the crop tell us if it can grow and needs nitrogen,” Ketterings said.
But its earlier readings may give poor prediction of nitrogen in the soil. Sometimes trying to use the equipment later can cause sensor-reading errors.
Preliminary testing on passive crop sensors—drones—shows the huge impact of timing. The equipment is susceptible to weather. Drones cannot fly in the rain. Clouds and sun glare can obscure the view.
The corn stalk nitrate test provides results later in the season, when it may be too late to significantly benefit corn; however, the results can help for the following year.
“I don’t think there was enough moisture for the roots to take up the nitrogen,” Ketterings said of the 2016-growing season in New York.
Though it’s tempting to treat the soil to more nitrogen during a drought, Ketterings said, “It’s hard to fertilize yourself out of a drought. It has become clear. You also can’t fertilize yourself out of a year where corn is standing in water.”
She added that cover crops or double crops can help use up unneeded nitrogen after harvesting corn.
“Keep the ground covered as much as possible and reduce tillage to conserve and build carbon,” Ketterings said. “When planting is delayed into June, consider alternative summer annuals.”
Ketterings said that her research team is looking at dwarf brachytic brown midrib forage sorghum.
“Evaluate if corn is yellow due to lack of nitrogen, lack of oxygen, or lack of moisture,” Ketterings said. “Make use of tools and technology. Build soil biological buffer capacity to create yield increase and stability over time.”
Building BBC includes building organic matter, reducing tillage, using manure where possible and cover cropping or double cropping.