With forage supplies tight in many areas, treating wheat straw with ammonia could provide a cost-effective option, according to Kansas State University Extension beef specialist Dale Blasi, PhD.
Ammonia improves the nutritional value of low-quality forage by swelling the plant tissue to allow greater rumen microbial activity, resulting in 8 to 15 percent improvement in digestibility, 15 to 20 percent improvement in palatability and increased rate of passage through the digestive tract. Also, ammonia serves as a non-protein nitrogen source, roughly doubling the crude protein value of the straw.
The process typically involves covering bales with a black plastic tarp and injecting anhydrous ammonia.
Historically, Blasi says, the recommended application rate was 3 percent anhydrous or 60 pounds per ton. But looking to reduce costs, K-State researchers have tested an application rate of 1.5 percent or 30 pounds of ammonia per ton of straw and found little difference compared with the heavier rate. Temperature and moisture content of the straw affect absorption of the ammonia. The process will take just three to five days in hot weather but up to 30 to 45 days in cold weather. Anhydrous ammonia will seek out all the moisture in the stacked straw, a chemical process that aids in uniform spread of the material. Eight to 10 percent moisture content in the straw is adequate, and 15 to 30 percent is better.
Keep the stack covered until two weeks before feeding, then remove the cover to reduce the concentration of residual ammonia. Blasi recommends against ammoniation of higherquality grass hays such as brome, fescue, small grains, forage sorghums or sudan grasses, as compounds dangerous to cattle can form in these types of hay exposed to ammonia. Blasi also stresses the importance of safety measures when handling anhydrous ammonia, including these tips:
• Wear goggles, rubber gloves and protective clothing. • Work upwind when releasing anhydrous ammonia into the stack. Ideally, use a de-coupler to disconnect the nurse tank away from the stack when application is complete.
• Have fresh water available to wash off any anhydrous ammonia that comes into contact with the skin.
• Check valves, hoses and tanks for leaks.
• Check the plastic cover on the stack for any tears in the plastic before initiating application. Seal any holes afterward with duct tape.
• Do not smoke near anhydrous ammonia.
• Keep children away from the treatment area.