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OSU Extension

College of Food, Agricultural, and Environmental Sciences

March 12, 2019 - 8:57am --

Our weather continues acting like a yo-yo, alternating between below average temperatures and above average temperatures.  We have also alternated between periods of snow cover vs. no snow cover, but through it all our soils remained saturated.  As a result, this has been a rough winter for wheat and alfalfa crops, so growers will need to be out scouting and assessing stand health and survivability of these crops in the next few weeks.  Today I am highlighting an early management decision regarding wheat fields; the application of spring nitrogen to fields that will stay in production.  As I have watched the price of straw at auction reports this winter, grain yield may not be the only consideration in deciding upon whether or not to keep a stand. 

This week, I am summarizing two articles from a recent OSU Extension crop team newsletter, an article on nitrogen application to weak wheat stands by Ed Lentz, Extension Educator in Hancock County and an article on manure application to wheat by Glen Arnold, OSU Extension manure management field specialist.  Read those articles in their entirety on-line at, or I can provide hard copies if someone needs that.

Ed Lentz says, “Late-planted wheat fields had little opportunity for growth before cold and wet conditions moved into the area last November. Fall tiller production was limited because of early cold weather soon after planting. In addition, some wheat stands have been damaged this winter from lack of snow cover, standing water, saturated soils, ice sheets, and days of very cold temperatures.  Producers have asked whether they should apply nitrogen earlier to increase the number of spring tillers.  Remember, fall tillers provide most of the yield in a wheat field. Heads developing from spring tillers generally are much smaller than heads from fall tillers.

From my experience, producers will have limited success in improving yields of poor stands and stands with reduced-growth by applying nitrogen earlier. A producer may get a few more spring heads, but not enough to significantly change the yield situation. The earlier application will also significantly increase the risk of nitrogen loss.  A practical compromise is to top-dress nitrogen any time fields are suitable for application after initial green-up (new plant growth has covered up the dead plant tissue) up to Feekes growth stage 6.  Recognize there is still a potential for nitrogen loss even at green-up applications.”

Regarding manure application to wheat, Glen Arnold says, “The key to applying the correct amount of manure to fertilize wheat is to know the manure’s nitrogen content. Most manure tests reveal total nitrogen, ammonia nitrogen and organic nitrogen amounts. The ammonia nitrogen portion is readily available for plant growth. The organic nitrogen portion takes considerably longer to mineralize and generally will not be available when wheat uptakes the majority of its nitrogen in the months of April and May.

Some Ohio commercial dragline operators are routinely applying livestock manure to wheat each spring. This practice is gaining acceptance, as it’s faster and more efficient than manure application with a tanker. The risk of soil compaction is also reduced.

Dairy manure has been utilized with on-farm research plots when topdressing wheat. Dairy manure contains far less ammonia nitrogen per 1,000 gallons than swine finishing manure and does not consistently produce wheat yields similar to commercial fertilizer. Research on dairy manure top-dressed on wheat by adding 28%UAN to the dairy manure to increase its fertilizer value has produced wheat yields similar to commercial nitrogen.

When applying livestock manure to wheat it’s recommended to follow the NRCS #590 Waste Utilization Standard to minimize potential environmental impacts. These standards include a 35 foot wide vegetative strip setback from ditches and streams.”


Grass Tetany Prevention

            Pasture-based cow/calf producers can take some steps now, and make plans to help prevent grass tetany from being a problem this spring.  Grass tetany, sometimes called grass staggers, is caused a low level of magnesium (Mg) in the blood.  It results in muscle spasms, and can progress to convulsions, respiratory distress and death.  Deficiencies in blood Mg levels occur most often in beef cows with a nursing calf that are grazing young, succulent grass in the early spring.  This includes cereal grain pastures.  A recent article by Michelle Arnold, Extension Veterinarian with the University of Kentucky, in the OSU Extension Beef Cattle Letter, says that high magnesium mineral mixes prevent grass tetany by allowing magnesium to passively flow into the bloodstream of the cow without the need for the active transport pump.  The recommendation is to begin supplementation with high magnesium mineral 30 days prior to calving.  Provide 4 ounces per day of a 15% Mg mineral mix per cow.  Continue until late spring when the grass is more mature and daily temperatures reach 60 degrees F or higher consistently.


Rory Lewandowski is an OSU Extension Agriculture & Natural Resources Educator and may be reached at 330-264-8722.

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