Much is said about the boosts in soil health and forage productivity seen from bale grazing pastures. Less is mentioned regarding the potential nutrient management concerns associated with this winter feeding method.
“The most un-talked about aspect of bale grazing is the potential nutrient loading and runoff that takes place,” says Idaho forage and grazing expert, Jim Gerrish.
Gerrish, who has consulted with producers on forage and grazing issues globally for more than 25 years, believes, conceptually, bale grazing is a good practice. Where he feels things sometimes go wrong is when beef producers don’t take the time to balance the needs of the soil with the nutritional value of the bales they’re placing in the field.
Similar to applying fertilizer to a crop field, bale grazing is a means to improve soil fertility in pastures. While less manure is concentrated and more efficient nutrient recycling obtained by bale grazing compared with confined feeding, the practice still poses environmental risks if practiced poorly or nutrients are over-applied.
“If you don’t change the location of bales from year to year, you end up with isolated islands of enriched soil immediately around where bales were placed,” says Gerrish.
Pastures can benefit from extra nutrients, but lack of uniform distribution and the potential for localized “hot spots” of nutrients are latent concerns. In addition, he warns, some producers just believe more is better.
“It’s the idea that if 10 bales per acre are good, 20 must be better, and 30 has to be fantastic,” says Gerrish. “But they don’t know how much nutrients are in a bale and that’s a problem.”
Recent research from Agriculture and Agri-Food Canada (AAFC), Canada’s equivalent to USDA, showed over a three-year period bale grazing led to increased nutrient concentrations in wetlands in the spring immediately following winter feeding. The nutrients exported were nearly 20 times higher than that from non-bale grazed sites ranging from 37-136 pounds per acre of nitrogen and 5.5-20 pounds per acre.
Soil type has been demonstrated to play part in nutrient runoff and leaching to shallow groundwater sources. AAFC’s research indicated more coarsely textured soils, such as the loam in the study, exhibited greater evidence of inorganic nitrogen leaching. Finer textured soils, like clay loam, showed less evidence of downward nitrogen movement. In addition, elevated phosphorus levels were found in the top meter of soil contributing to higher dissolved phosphorus in shallow groundwater sources.
Alberta bale grazier Grant Lastwika agrees runoff is a concern: “We must consider what we are putting on the landscape so we can mitigate losses and issues of it possibly getting into waterways.”
Besides being a rancher, Lastiwka also works as a forage and business livestock specialist with the Alberta Department of Agriculture and Forestry. Alongside his twenty-plus years of bale grazing experience, he has also worked with producers across Alberta to improve forage and grazing management.
Gerrish and Lastwika both stress producers who bale graze livestock should take proactive management to tackle these possible nutrient management problems. In turn, they will improve the fertility of their land base in a manner while reducing water quality and nutrient overloading risks.
For graziers to do this effectively, Gerrish says, start with determining the nutrient status and needs of bale grazing sites. An annual soil test can provide a baseline and assist in keeping nutrient build-up in check. When taking samples, care should be taken to obtain representative specimens of the entire pasture including high-traffic bale sites and lower-use areas of the same field.
“Know how much fertility you need to put on the ground and don’t put out any more bales than that,” says Gerrish. “That might mean you need to bale graze fields more or less frequently than you planned otherwise.”
On the flipside, Lastwika says producers also need to know the weight and forage quality of the bales they are feeding to manage properly.
“Weigh and feed test your bales so you know what you’re working with,” says Lastiwka. “If you don’t know what you have, you can’t manage it and that can be dangerous.”
Armed with this information, Gerrish explains, producers can develop specific targets for individual nutrients such as nitrogen, phosphorus and potassium, they want to add to the soil and feed bales accordingly.
Along with balancing soil and livestock’s nutritional needs, care should be taken to choose the right bale grazing site locations. Gerrish and Lastwika both suggest keeping bale grazing activities away from sloped areas, creeks, edges of drainages, and other water bodies.
Moreover, bale sites should be rotated in fields on an annual basis. Lastwika says GPS is a handy tool to keep track of bale sites over the long term. He recommends rotating bale sites in a pasture on at least a four-year basis.
Ultimately, however, Lastwika says, “It comes down to managing intensively with thought and flexibility because the fact is one year to the next is never the same.”
Three bale grazing resources
Hay as Fertilizer Calculator - This calculator is designed to determine the quantity of nutrients from hay feeding that can be returned to the soil as added fertility. Available from American GrazingLands Services, LLC. Email [email protected] for more info.
Bale Grazing Calculator - A tool developed by the Saskatchewan Ministry of Agriculture to help producers estimate the cost of feeding livestock with bale grazing. Download for free at http://publications.gov.sk.ca/details.cfm?p=75821.
The Basics and Benefits of Bale Grazing - This is a Canadian publication which outlines dos and don'ts for bale grazing management, as well as recommendations on feeding guidelines to reduce nutrient management risks. Available for free download at https://www.gov.mb.ca/agriculture/livestock/production/beef/pubs/baa05s04j.pdf.