Importance of Testing For Nitrates

As the time to harvest your annual forages draws near and because nitrate toxicity can be fatal for your livestock, it is important to understand the need for nitrate testing.

Cereal crops are known to accumulate nitrates with oats being the top accumulator, along with wheat, barley, rye, triticale, spelt, and others. Other problematic crops include sorghum, sudangrass, millet, and corn. Many weed species can accumulate nitrates, as well, such as kochia, pigweed, lambsquarter, quackgrass, and Russian thistle. If you are growing any of these crops for forage or have forage that has a large amount of these weeds, you should consider testing for nitrates.

Nitrate is a form of nitrogen, which is essential for plant growth and development. This is the form that is taken up by a plant’s roots. Under normal growing conditions, plants will turn this nitrate into nitrite, then to ammonia, and then to amino acids to build proteins. However, in some cases, nitrates are taken up faster than the plant can convert them to protein. This accumulation varies greatly by management, soil fertility, part of the plant, plant maturity, and growing conditions. Any condition that stresses the plant can increase nitrate accumulation, including drought, disease, hail, soils high in nitrate or deficient in minerals, shade, herbicide damage, frost, or over fertilized soils. Insect damage, from insects such as grasshoppers, is another stressor that can increase nitrate accumulation. Even under the most ideal conditions, nitrates can still be unpredictable. Therefore, it is important to get your forages tested, prior to harvesting them.

Within the rumen of an animal, nitrates are typically converted to nitrite by rumen microbes, then into ammonia, and that ammonia is then used as a protein source for the rumen microbes. When there is a large influx of nitrates into the rumen, nitrite accumulates faster than it can be converted into ammonia. This nitrate is absorbed into the bloodstream and reduces the blood’s oxygen carrying capacity, which can ultimately lead to suffocation and death. Other symptoms of nitrate toxicity include weight loss, abortion, weakness, and reduced performance. Because of the high risk and speed of nitrate toxicity, the best treatment is prevention, making it extremely important to have your forages tested.

Here at the Extension Office, we offer a free in-house semi-quantitative nitrate test that provides same day results. If you have any questions or need to have a nitrate test done, stop by the office or call 406-433-1206.