Variability of Phosphorus Concentration in Runoff and Seepage Water from Agricultural Production Systems

Phosphorus (P) is an essential nutrient needed for growth of plants and animals and a common nonpoint-source pollutant contributing to eutrophication of natural water resources. We investigated the impact of soil management practices used to promote crop yield on the concentration of P in runoff and seepage (infiltration) water from soil amended with animal manures following rainfall events. A field experiment in summer 2021 at Kentucky State University H.R. Benson Research and Demonstration farm was established using five soil management practices: sewage sludge SS, chicken manure CM, Biochar Bio, chitin CH, and no-amendment (NA) native soil used for comparison purposes. Runoff water was collected using tipping bucket apparatus, whereas infiltration water was collected using pan-lysimeters during three rainfall events. Results showed that biochar treatment was effective in reducing runoff water down the field slope compared to other soil treatments. The addition of biochar to native soil significantly reduced total P concentration in runoff water by 62% compared to soil amended with CM. Similarly, biochar reduced P concentration in infiltration water by 52% compared to CH treatment. We concluded that application of biochar and routine analysis of P in runoff and infiltration water is necessary for appropriate remediation of P contamination of natural water resources