Local assessments of the impacts of phosphorus index implementation in Pennsylvania

Wilhelm J. Kogelmann, Ray B. Bryant, Hangsheng S. Lin, Douglas B. Beegle, Jennifer L. Weld

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


The phosphorus (P) index is the preferred method of implementing P-based nutrient management plans in Pennsylvania. The P index is a field level risk assessment tool that quantifies P source and transport factors to determine if management changes are necessary to avoid off-site transport of P to surface waters. It is important for conservation officials to understand the effect P restrictions will have on farms and farming communities. This study applied the P index to 276 fields on 13 farms in two Pennsylvania counties, Lancaster and Snyder, which were previously identified as having the potential to face severe restrictions under P-based nutrient management. Of all soil samples, 18 percent exceeded the 200 ppm environmental soil P threshold which triggers full assessment under the P index. Lancaster County had significantly greater soil P test levels compared to Snyder County. Trends of increased soil P test and increased P restriction were observed as animal density increased. Additionally, soil P levels on land with animal concentration areas exhibited significantly greater soil P, compared to cropland and pastures. Preliminary screening based on soil test P levels and proximity to water, indicated that full P index assessment was required for 46 percent of the fields in Lancaster County and 19 percent of the fields in Snyder County. This indicates that Lancaster will face greater nutrient management planning costs. After applying the full P index, Lancaster and Snyder Counties had 31 and 12 percent of the fields P restricted, respectively. Four highly impacted farms were closely examined to determine the feasibility of complying with P restrictions. Two farms were able to comply with on-farm options, and two required a solution that would require moving P offsite. Farms studied were representative of localities where animal agriculture is a critical part of the economy. The large proportion of fields restricted under the P index-20 percent of all fields studied-indicates that technical and financial assistance may be required to allow these operations to remain economically viable. Additionally, conservation officials need to be mindful of the need for long-term solutions that address the fundamental problem of regional nutrient surpluses.

Original languageEnglish (US)
Pages (from-to)20-30
Number of pages11
JournalJournal of Soil and Water Conservation
Issue number1
StatePublished - 2006

All Science Journal Classification (ASJC) codes

  • Agronomy and Crop Science
  • Water Science and Technology
  • Soil Science
  • Nature and Landscape Conservation


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