With most of western North Dakota experiencing abnormally dry to severe drought conditions, and some counties receiving less than 2 inches of rainfall between July and August, there's growing concern about high nitrate levels in forages. Elevated nitrate levels can be toxic to livestock, and this concern increases when farmers consider cutting failed crops for hay or silage.

Nitrate accumulates in soils during drought periods due to microbial activity. Soil microbes produce nitrate as a byproduct of their metabolism. Under normal moisture levels, nitrate dissolves in water and is taken up by plants to produce proteins. However, when soils are dry, nitrate doesn’t move into the roots, leading to an accumulation in the soil. Once rainfall occurs, this stored nitrate dissolves rapidly, creating a surge in nitrate uptake by plants.

Environmental stresses that significantly slow plant photosynthesis and metabolism can cause plants to accumulate excessive nitrate. In these cases, nitrate uptake exceeds the plant's ability to convert it into protein, leading to high nitrate levels in the plant.

When ruminants ingest excessive nitrate, rumen microbes convert it to nitrite faster than they can convert nitrite to ammonia and protein. This nitrite buildup can then be absorbed into the bloodstream, reducing the ability of red blood cells to carry oxygen, potentially suffocating the animal.

Given these dry conditions, ensuring enough forage for hay or grazing is a concern. Using drought-affected crops as feed is common, but it carries risks. Testing for nitrates before grazing or haying is critical to managing this risk.

Key Recommendations:

• Test before grazing or haying: NDSU Extension offers the Forage Nitrate QuikTest, a screening tool to detect nitrate in standing forage. Certified Extension agents can perform this test in the field or at the office. Producers should collect a representative sample by clipping at least 20 stems at ground level in a zigzag pattern across the field.
• If nitrate levels are high: Delay harvest to allow nitrate levels to decrease.
• For harvested forage: If forage has already been cut, the QuikTest cannot be used. In this case, use a bale probe to collect core samples and send them to a lab for analysis. Be sure to follow your forage lab’s guidelines for sample collection, packaging, and shipping.

For more information on nitrate toxicity and testing, contact your local NDSU Extension agent or refer to the following NDSU Extension publications:

·        Test Forages for Nitrate Before Grazing or Feeding

·         Nitrate Poisoning of Livestock