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Manure 101: Manure has value, test and take credit this spring

Myth #1: Manure that is spread during the winter and not incorporated has very little nitrogen left for the next corn crop.

Reality: Winter-applied manure will have nitrogen value! When manure is spread during cold weather and the soil has moisture, much of the nitrogen is held in the soil and is available in the spring. Keep in mind a late summer application of manure N on wheat stubble may lose some of the organic nitrogen by next spring’s corn crop.

As soon as soils warm up in the spring, a portion of the nitrogen in the organic fraction is released and is readily available to the growing crop. Nitrogen will be available to the next crop, even from surface applied manure when it is applied during cooler weather.

Myth #2: Manure spread in March and April will not be available to corn in June.

Reality: Nitrogen in manure comes in several forms including ammonium-N (NH₄-N) and organic. As the soil warms up in the spring, up to half of the organic nitrogen converts to nitrogen that is readily available to the growing crop. If the manure was injected, this organic nitrogen is available along with most of the readily available ammonium fraction. Manures like open lot beef manure or broiler barn litter, or manure’s that are surface applied have minimal ammonium-N. The organic nitrogen in these manures is a slow-release nitrogen. A fertility program that supplements manure’s organic nitrogen with inorganic fertilizer, possibly a starter fertilizer, can help with early crop vigor.

Some research has demonstrated that peak yields are observed for manure application at rate replacing roughly 75% of the crop N requirements, with supplemental commercial fertilizer used for the balance. Manures with significant ammonium-N content (and injected) may have less need for supplemental fertilizer for the early season vigor. | READ MORE