Cameron Mills says he won't be applying as much nitrogen on his corn this year as he did last year. That doesn't mean he expects any less yield, however. He has confidence that he has built up soil health and will have enough nitrogen released from cover crop residue to help supply N that the crop might need in addition to commercial N fertilizer.

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No nitrogen deficiency here: Cameron Mills says his corn didn't run out of N in 2015. Since he grows cover crops, he plans to apply even less N this year.

When he started farming with his father in conventional tillage, Mills, Walton, says they often applied 200 or more total pounds of N per acre. He's reduced that over time. This year he's looking at applying about 130 pounds per acre of N in most situations in corn after soybeans, with part of it applied as starter fertilizer and the rest applied at sidedressing.

Mills is hardly shooting in the dark. Bio-mass sampling over the past few seasons have shown him how much N is captured in biomass by cover crops. He is partial to annual ryegrass and rapeseed on most of his acres where corn follows soybeans.

The biomass tests tell him that the cover crops scavenged up nitrogen and kept it on his farm, not letting it leave. Through other calculations, he has tried to zero in on when most of that N will be released, and how much he can count on to be released for the crop during the first year. He has grown cover crops as part of his no-till system for the past nine years.

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He intends to further zero in on N release times by conducting more detailed sampling this season.

While he kept hearing that he should apply more N on his corn after receiving huge amounts of rain last year, he didn't. And his corn was still green late in the season. It yielded well, and he says that as it turns out, it obviously didn't need large amounts of N that some recommended as rescue treatments last year.