Impacts of cattle penning on groundwater quality beneath feedlots.

摘要

The groundwater quality of five 20 to 35 year old cattle feedlots around Saskatoon were investigated. Water samples were obtained from 30 piezometers (2.5 to 14.5 m deep) during three sample times (February, June, and August of 1997). All piezometers were located outside the feedlot pens but within or adjacent to the feedlot area. The objective of this study was to determine whether shallow groundwater within the feedlot area is contaminated by feedlot manure. Elevated concentrations of the following ions were found to indicate the presence of manure in groundwater; K+, Cl-, NO3-N, NH4-N, and total dissolved P. Due to the absence of baseline data, two different levels of concentration were used; a lower level to divide waters between 'background'and those with perhaps some indication of agricultural activity (i.e. poor fertilizer management); and an upper level to indicate the definite presence of feedlot manure. Of the five sites, four displayed concentrations indicative of feedlot manure. Of the 30 piezometers, only two had low concentrations that could be considered background, that is showing no indication of being affected by any human activity. The high degree of groundwater contamination as evidenced by the piezometers, could be a function of the shallow levels, only eight piezometers had water levels deeper than 4 m.