Pennsylvania Horse Farm’s Whole Farm Balance Inputs of Nitrogen and Phosphorus

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In Pennsylvania there has been an increased emphasis on farm and nutrient management practices on equine operations due to expansion of environmental regulations. Of the 31,000 operations which house horses in Pennsylvania, 23,250 are non-commercial operations and over 75 percent are on limited acreage, requiring intensive management. Managers of equine operations frequently do not have agricultural backgrounds and need assistance with farm management plans. Proper management of equine operations requires a series of complementing Best Management Practices (BMPs) that implement strategies to preserve pasture vegetative cover, to balance nutrient production with nutrient utilization, to properly manage excess manure nutrients, and to manage equine operations for minimal release of sediment.

This environmental program was developed to identify needed BMPs for the equine industry and help farm mangers understand, select, and implement sustainable farm management practices. The program consisted of three components: Documentation of existing practices and conditions on equine operations, educational outreach to increase knowledge and skills, and on-farm implementation of BMPs. These three projects covering 2009-2015, measured sediment and nutrient losses, for high density horse operations; and recorded environmentally sound farm management practices.

What did we do?

Swinker in pastureProject 1- documented conservation and farm management practices on 23 equine operations, quantitatively evaluated pasture desirable plants and canopy cover, sampled feed, hay and soil, and conducted nutrient management audits. Pasture data, collected using line point transect methodology, included calculation of percent canopy cover, basal stems and desirable forage. The 23 surveyed operations were used to develop a baseline for total nutrient balances and levels for the Pennsylvania horse industry.

Project 2- looked at nitrogen and phosphorus inputs on 14 farms to determine the risk of horse farms for non-point source pollution. Over a 12 months period, amounts of imported fertilizer, hay, concentrate feed, and bedding were obtained from farm managers. Samples of hay, concentrate feed, and bedding were taken from each farm and analyzed for N and P. Whole farm nutrient balance was calculated as a percent by the equation ((imported nutrients- exported nutrients) /imported nutrients) X 100. Nitrogen and P whole farm balances were recorded as a percentage basis for the total farm and on a kilogram basis for per animal unit and per hectare values. PROC SURVEYMEANS was used to determine descriptive statistics on the sample and whole farm balance values.

Project 3- involved 95 farm operations (1,086.90 ac.) in a project designed to implement practices to increase canopy cover and desirable forages in pastures and reduce nutrient and sediment loss. The team provided individual assistance to help owners locate resources, technical assistance and funding. All farm managers (n=95) farms were visited documenting conservation/management practices, BMPs already in place and identification of areas of concern/improvement needs. The team finalized field farm survey instruments, quantitatively documented pasture plants/canopy cover, sampled feed/hay/soil, and conducted nutrient management audits. Pasture data was collected using line point intercept and Equine Pasture Evaluation Disc methodology. All plant species were documented with pasture condition scores generated using pasture condition score sheets.

Out of the 95 farms visited, a total of 43 farm (744.55 ac. collectively), pastures were targeted for improvement, soil tested and prepared for methods to improve the pasture grass stands. Farms selected to reseed pastures were provided with a seed mix that was custom blended for their farm based on soil conditions, farm management, pasture needs and level of use.

Twenty-seven of the farms conducted reseeding using a no-till drill, 8 farms utilized conventional plowing and 8 farms utilized broadcasting and/or frost seeding. The remaining 48 farms did not need to reseed and instead received recommendations on methods to improve and manage existing forage quality through improving or utilizing BMPs. Four farms did not continue involvement in the program after the initial farm visit by the team.Picture of two horse in a pasture

What have we learned?

Project 1- The surveyed farms have helped to validate and evaluate existing tools on horse operations. The “pasture sediment loss” tools used (at that time) in this project (PA RUSLE2, Pasture Condition Score, Nutrient Balancing, Pasture Nutrient Balancing sheets and PA Phosphorous-Index) helped to analyze the cost-effectiveness and sustainability of the nutrient reduction strategies. The survey results have shown that these selected tools need to be adjusted in order to properly measure sediment and soil loses on horse farms.

Smaller farm operators reported a major hurdle to managing pastures is lack of knowledge and lack of equipment. In addition, 33% of farm managers reported they wanted to utilize the suggested practices, but required financial assistance or more technical information.

Results of the information gathered by the Equine Environmental Stewardship (EES) team projects has been used and examined by state agencies, assisting in development of in-service training for their personnel, used in revising potential regulations and assistance concerning horse farm operations.

Study 2- The majority of the horses on the farms were non-breeding horses, which the only managed output was manure. Four of the farms did not export any manure, 3 exported a small portion of their collected manure and 6 exported all their collected manure. Whole farm balance inputs averaged 53 kg N per 1000 lbs of animal (AU) and 13 kg P/AU. Whole farm balances ranged from 100% retention of imported nutrients where no products were exported to a negative balance where all collected manure was exported. Average N and P whole farm balances were 73% and 51% retention of inputs, respectively. With limited export of nutrients from horse farms as foals or manure, more manure must be exported and/or nutrient imports must be decreased to approach nutrient balance and decrease the risk of nutrient pollution.

Project 3- Out of the 95 farms visited, a total of 43 farms (representing 744.5 acres) were reseeded. Twenty farms needed to utilize the no-till drill purchased through the project grant. Pastures chosen for reseeding had low forage yields and canopy covers less than 50%. After reseeding the pastures, yields increased to 1.0 to 2.0 tons per acre resulting in an economic gain that averaged $450 to $600 per acre.

In conclusion: The Team noted that farm owners are committed to adopting practices that maintain healthy horses, healthy farms, and a healthy environment. Each of the farms listed worked with the Equine Team to select and implement one or more Best Management Practices (BMPs) on their farm. BMP’s were chosen to increase pasture canopy cover and improve pasture quality, proper composting and or disposal of manure, and ration formulation. Practicing rotational grazing, utilizing sacrifice areas, soil testing and applying lime and fertilizers are BMPs farmers were encouraged to adopt.

Future Plans

The survey results are being used in the development of the curriculum for Environmental Stewardship short courses, to help agency personnel understand the equine industry and to help farm owners develop the knowledge and skills necessary to adopt environmentally sound farm management practices.

Corresponding author, title, and affiliation

Ann Swinker, Extension Horse Specialist, Pennsylvania State University

Corresponding author email

Additional information

Ann Swinker

Penn State University

324 Henning Building

Department of Animal Science

University Park, PA 16802


FAX: 814-865-7442


Bott, R., Greene, E., Trottier, N., Willliams, C., Westendorf, M., Swinker N., Mastellar, S., Martinson, K., Environmental implications of nitrogen output on horse operations: A review, Journal of Equine Veterinary Science 08/2015; DOI:10.1016/j.jevs.2015.

Swinker, A., D. Foulk, H. McKernan , Environmentally Friendly Farm Program Recognizes Pennsylvania Farms that Adopt Sound Management Practices Protecting Water Quality and the Environment, Waste to Worth, Seattle WA, March 31 – April 3, 2015.

USDA, CIG Grant Final Report: Pennsylvania Small Farm Environmental Stewardship Program: Implementing Conservation Practices on Small Farms and Using Environmental, Agreement Number: 69-3A75-11-180. 56 pages.

Swinker, A. M., Northeast Regional USDA CRIS Report, September 2013, USDA Regional Project, NE-1041 – Environmental Impacts of Equine Operations,

PSU DAS web site; Environmental stewardship Project and Equine Science Newsletter websites


USDA Natural Resource Conservation Service Conservation Innovation Grant and SARE Grant for funding this project. USDA Regional Project, NE-1041, All the hard work of the PSU Extension Equine Team

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