A livestock nutrient management system is designed to collect, transfer, store, treat and finally utilize nutrients generated from animal wastes, from the point of production to beneficial integration into a cropping system. The system is planned and designed to manage the nutrients and pathogens, normally associated with a livestock operation, in a manner that would protect the natural resources (water, soil, air) in the surrounding environment. The USDA Natural Resources Conservation Service provides excellent technical resources in planning and implementation of animal waste management systems.
Beneficial Use of Nutrients
The term “nutrient”, compared to the term “waste”, better describes the managed system. The waste stream generated from livestock operations should not be viewed as a liability, but as an excellent resource and asset to the operation. Through an efficiently designed system that integrates the treatment, storage and beneficial utilization components, the “wastes” are converted into valuable “nutrients” that can be used to enhance the sustainability of local food production systems. Incorporating composting technology, as part of the treatment component, creates a valuable organic soil amendment that will provide quality plant nutrients (fertilizer value) and beneficial microorganisms for crops. Nutrients derived from the livestock operation can reduce the imports of chemical fertilizers, then in turn be used to grow crops for improved community food security, be used to produce and supplement feedstock for the livestock operation, or be sold to other farmers to improve the economic returns for the piggery operator.
Another way to evaluate the value of the recovered nutrients is to correlate the cost of the feed with an estimated digestibility of the feed. Digestibility varies across the different feed ingredients, but in general dry matter digestibility for commercial feeds range from 70% to 80%. For example, if commercial hog feed in local stores cost $30 for a 50‐pound bag and given a digestibility estimate of 80%, will result in a 20% loss of nutrients through manure. For every bag of feed used will result in a net loss of $6.00 when the manure is simply washed onto the ground or into streams. If a farmer feeds five bags of feed per day, the potential daily loss is equivalent to $30. By recovering the manure, both valuable nutrients and monetary resources are captured. Through a systematic composting system, the nutrients can used for improved food production resulting in fertilizer cost savings on the farm or the nutrients could be sold as a fertilizer/soil amendment for additional revenue to the operation.
Another way to evaluate the value of the recovered nutrients is to correlate the cost of the feed with an estimated digestibility of the feed. Digestibility varies across the different feed ingredients, but in general dry matter digestibility for commercial feeds range from 70% to 80%. For example, if commercial hog feed in local stores cost $30 for a 50‐pound bag and given a digestibility estimate of 80%, will result in a 20% loss of nutrients through manure. For every bag of feed used will result in a net loss of $6.00 when the manure is simply washed onto the ground or into streams. If a farmer feeds five bags of feed per day, the potential daily loss is equivalent to $30. By recovering the manure, both valuable nutrients and monetary resources are captured. Through a systematic composting system, the nutrients can used for improved food production resulting in fertilizer cost savings on the farm or the nutrients could be sold as a fertilizer/soil amendment for additional revenue to the operation.