Evaluation for Impacts of Nitrogen Source to Groundwater Quality in Livestock Farming Area

Abstract

We investigated 52 livestock farming complexes in Gyeong-Gi and Incheon provinces based on low, medium, and high livestock density and groundwater quality. The objective of this study was to evaluate a relationship between nitrate N concentration in groundwater and animal factors, such as livestock density and animal species. 2,200 groundwater samples for 3 years from 2012 to 2014 at Gyeong-Gi and Incheon provinces were collected and analyzed for pH, EC, DO, ORP, temperature, major anions and cations, such as NO3-N, HCO3-, PO4-, SO42-, Cl-, NH4-N, K+, Na+, Ca2+, Mg2+, T-N, and TOC. Average concentration of total N for generated load density was 23,973 g day-1 km-2 for cattle, 51,551 g day-1 km-2 for pig, and 52,100 g day-1 km-2 for poultry. For animal feeding species, average ratio for generated load over discharge load was 16.1% for cattle, 7.8% for pig, and 7.1% for poultry. Therefore, cattle feeding region is highly vulnerable for water pollution compared to pig and poultry feeding areas. The concentrations of chloride, nitrate, and total N in the groundwater samples were higher at high animal farming regions than other regions. The average concentration of nitrate, and chloride in groundwater samples was 5.0 mg L-1, 16.6 mg L-1for low livestock density, 6.9 mg L-1, 17.7 mg L-1for medium livestock density and 7.6 mg L-1, 22.7 mg L-1for high livestock density and total nitrogen (T-N) was 7.7 mg L-1for low livestock density, 9.4 mg L-1for medium livestock density, 10.7 mg L-1for high livestock density. In conclusion, based on this research, for managing groundwater quality near livestock farming regions, Ca-(Cl+NO3) group from the Piper diagram is more efficient than using 19 factors for water quality standard. Correlation between generated load and generated load density from monitoring agro-livestock farming areas.