Illinois Environmental Protection Agency Cedar Creek/Cedar Lake TMDL Implementation Plan
48 Final Report
The NRCS provides additional information on prescribed grazing at
in Section IV B. Conservation Practices Number 528A
and on grazing practices in general at
Maintaining sufficient ground cover on pasture lands requires a proper density of grazing animals and/or
a rotational feeding pattern among grazing plots. Increased ground cover will also reduce transport of
sediment-bound manganese. Dissolved oxygen concentrations in streams will likely improve as the
concentrations of BOD5 in runoff are reduced proportionally with the change in number of cattle per acre.
The following reductions in loading are reported in the literature:
• 49 to 60 percent reduction in total phosphorus loading
• 40 percent reduction in fecal coliform loading as a result of grazing land protection measures
• 90 percent reduction in fecal coliform loading with rotational grazing (Government of Alberta,
The costs associated with grazing land protection include acquiring additional land if current animal
densities are too high (or reducing the number of animals maintained), fencing, and seeding costs, and
developing alternative water sources. Establishment of vegetation for pasture areas costs from $39/ac to
$69/ac based on data presented in the EPA nonpoint source guidance for agriculture (USEPA, 2003).
Annual costs for maintaining vegetative cover will likely range from $6/ac to $11/ac (USEPA, 2003). If
cattle are not allowed to graze plots to the point of requiring revegetation, the cost of grazing land
protection may be covered by the fencing and alternative watering strategies discussed above.
4.16 Feeding Strategies
Use of dietary supplements, genetically enhanced feed, and specialized diets has been shown to reduce
the nitrogen and phosphorus content of manure either by reducing the quantity of nutrients consumed or
by increasing the digestibility of the nutrients. Manure with a lower nutrient content can be applied at
higher rates to crop land, thus reducing transportation and disposal costs for excess manure.
Manure typically has a high phosphorus content relative to plant requirements, and also compared to its
nitrogen content. Nitrogen losses due to ammonia volatilization begin immediately following waste
excretion and continue throughout the stabilization process, whereas phosphorus remains conserved. In
addition, most livestock animals are not capable of efficiently digesting phosphorus, so a large percentage
passes through the animal undigested. Compounding the problem is over-supplementation of phosphorus
additives relative to nutritional guidelines, particularly for dairy cattle (USEPA, 2002a).
Most feeding strategies work to reduce the phosphorus content of manure such that the end product has a
more balanced ratio of nitrogen and phosphorus. Reducing the phosphorus content of manure will result
in lower phosphorus concentrations in runoff and stream systems. Feeding strategies will indirectly
impact dissolved oxygen concentrations by reducing eutrophication in streams and lakes. The USEPA
(2002a) reports the following reductions in phosphorus manure content:
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