The effect of farm liquid waste application on tile drainage

AGRICUTURAL drains in Ontario often have high bacterial, nitrogen, and phosphorus concentrations. The Ausable Bayfield Conservation Authority ( 1 ) and the Ontario Ministry of the Environment ( 5 ) have established that in some cases land application of liquid manure causes bacterial and chemical contamination of field tile drains. That contamination may result in beach closures due to elevated bacterial concentrations and excessive algal growth. In a field study by Patni and Hore (6) , tile drainage generally was unaffected by manure spreading on fields, except when a heavy rainfall occurred. On the other hand, Evans and Owens (2) found a 30 to 900 fold increase in fecal bacteria concentration in the tile effluent from a sandy clay loam pasture field within two hours of spreading liquid manure. A one-time observation by Patterson and associates (7) found the water from five-foot deep drains in a plowed field to be cloudy and foul smelling within 30 minutes after a 0.2-inch application of …