Use of hail-damaged crops for livestock feed has nitrates concerns

Nitrates in hail-damaged crops used for livestock feed need careful management. Nitrate levels occur when a plant no longer can efficiently convert nitrates to protein, says Barry Yaremcio, beef and forage specialist with Alberta Agriculture. After the storm, water and nutrients are still pushed from the roots to the plant. Nitrates accumulate on the top leaves with concentrations peaking about four days after hail injury.

If plants recover and new growth develops nitrate levels can return to normal in 12 to 14 days.

Soil fertility and stage of crop development are critical to nitrate accumulation. “Crops such as canola and wheat have high amounts of nitrogen fertilizer applied,” he said.

“If the crop is thin and not overly productive, there could be significant amounts of soil nitrogen available in the soil well into July. A crop that is thick with high yield potential would use up most of the available nitrogen much earlier in the growing season. With less nitrogen left in the soil, there is less available to be transported into the plant.”

Hay crops tend to have lower fertility than annual crops, so the risk of a hay stand having high nitrate concerns is much lower than an annual crop.

“Alfalfa and legume crops - peas, clovers, vetches - have nodules in the root system that regulate nitrate transport into the plants. The nodules only allow as much nitrogen into the plant as is needed, so it is extremely rare to have nitrate accumulation in legume forages.”

Feed testing labs can test for nitrates. Samples taken four days after the storm can show the worst-case situation. He recommends talking to your feed salesperson or company nutritionist, nutritional consultant, or contact agrologists and talk to a livestock specialist.”