Production Blog

Snow Days Offer Free Fertilizer for Farmers

Jason Jenkins
By  Jason Jenkins , DTN Crops Editor
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Every snowfall can deposit nitrogen in farm fields, though the exact amount can vary by region and the type of snow. (DTN photo by Jason Jenkins)

JEFFERSON CITY, Mo. (DTN) -- As we near the final week of February, much of "farm country" finds itself wrapped up snugly under a blanket of snow.

According to remote sensing analyses from the National Oceanic and Atmospheric Administration, the white stuff currently covers more than half of the continental United States, including 51.5% of the Western Plains, 85.4% of the Midwest and 94.9% of the Upper Midwest.

There's no doubt that snowstorms present challenges. Travel plans get delayed. Sidewalks must be shoveled. High school basketball games are rescheduled or canceled altogether. Livestock can require extra hay and supplemental feed.

Yet there are advantages to snow. Of course, precipitation in any form can help recharge moisture in the soil profile ahead of the coming growing season. For those growing wheat or other overwintering crops, a blanket of snow can provide protection from extremely cold temperatures that can cause winterkill.

But snow can also bring another benefit to fields and pastures: fertility. Snow contains nitrogen and other elements such as sulfur, earning it the nickname, "Poor Farmer's Fertilizer."

Most of the air we breathe is comprised of nitrogen, but it's in a stable, inert form that's not available to plants. However, the atmosphere does contain other nitrogen compounds known as nitrogen oxides, designated as "NOx." Some are created naturally by lightning; others are the result of fossil fuel combustion. As snowflakes form, they encase these compounds in their crystal structure. Dense, wet snow contains more moisture and less air, so it has less nitrogen. Light flaky or fluffy snowflakes contain more air and therefore have more nitrogen in them.

HOW MUCH NITROGEN?

The National Atmospheric Deposition Program (NADP) has measured nitrogen and other nutrients in precipitation around the country since the late 1970s. Annual levels of nitrogen deposits from precipitation can vary. Regions with higher levels of NOx will typically have snowfalls with higher concentrations of nitrogen deposition.

A little Internet sifting uncovered some work done by Ron Gelderman, then-South Dakota State University Extension soils specialist, back in 2013. He measured the nitrogen contained in a single 9-inch snowfall event that fell in Brookings, South Dakota. The snow equated to about 2 inches of liquid water and contained 0.3 pounds per acre of available nitrogen. NADP estimates that annual deposits from precipitation can range from about 5 pounds per acre on the western edge of the Corn Belt to 12 pounds per acre in the Eastern Corn Belt.

Late fall/early winter and late spring snowfalls are most beneficial because the ground is not frozen. As these snows melt, they slowly release nitrogen into the soil profile where microbes can fix this nitrogen, converting it to ammonia or nitrates that can be used by plants or by other microbes in the soil.

So, while it's not enough nitrogen to change your application rates for anhydrous or urea, I say let it snow. Every little bit helps.

Jason Jenkins can be reached at jason.jenkins@dtn.com

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