Producers with wheat damaged by the recent frost have some difficult decisions to make, which may be limited to some extent by crop insurance requirements.
"Many fields have a combination of standing, freeze-damaged wheat and patches of downed wheat," says Jim Shroyer, K-State Research and Extension crop production specialist.
If the freeze damage is severe, one option is to use the wheat as a forage crop – either by cutting it for hay or grazing it out. Before haying or grazing, producers should first have the wheat tested for nitrate levels, adds David Mengel, K-State Research and Extension soil fertility specialist. This applies to any freeze damaged crop.
"A very limited number of freeze-damaged wheat samples taken recently have shown high nitrate levels - 6,000 to 15,000 parts per million (ppm) - in the forage. The highest values came from fields fertilized shortly before the freeze," Mengel says. "Therefore, producers wanting to graze or hay this wheat should test it for nitrates before turning cattle in or cutting for hay. The potential for problems is great."
Nitrate levels higher than 6,000 ppm can potentially be toxic, depending on the situation.
Canola and other brassicas are known accumulators of nitrates, Mengel adds.
"It is likely that freeze-damaged canola will contain high nitrates. Producers planning to graze freeze-damaged canola should test for nitrates first," he says.
The potential also exists for freeze-damaged alfalfa to have high nitrate levels, although this is much less likely. High nitrates in alfalfa would be especially likely in fields where manure was applied last fall. Therefore, testing might be advisable if there was a nitrate source present.
More information is available in the "Nitrate and Prussic Acid Toxicity in Forage," K-State Research and Extension publication: www.oznet.ksu.edu/library/crpsl2/MF1018.PDF.
If the decision is made to hay or graze growing wheat, producers have until the late-boot stage to harvest the forage before the nutritional quality begins to decline sharply, says John Fritz, K-State Research and Extension forage management agronomist.
If the crop was already in early heading when damaged and awns are present, this can cause cattle considerable soreness and irritation to the eyes, mouth, lips, gums, and lower surface of the tongue, says Ron Hale, K-State southwest area Extension livestock specialist. "In general, a crop with rough awns should be ensiled rather than hayed or grazed. If the crop can be picked up, it can be made into wheatlage as long as it still contains about 30 to 35% dry matter and 65 to 70% moisture," Hale says.
To cut the crop for hay (or silage), a sicklebar mower can be used to slide under the down wheat to cut it. Rake and bale as usual. Grazing can begin at any time the ground is dry enough, pending crop insurance considerations. Care must be taken when grazing to minimize soil compaction.
"Dead wheat should be grazed as soon as possible, as nutritional quality will decline immediately. To maximize grazing potential, the wheat should be strip-grazed, using a heavy stocking rate and moving the electric fence daily. Animals will need an adequate water supply," Fritz says.
Cattle on wheat pasture are often "washy" due to the high moisture content and digestibility of the wheat, he adds. Offering dry, lower-protein hay or allowing access to native range can minimize this condition.