| Zero tillage (ZT) is increasingly adopted in Atlantic Canada due to its soil erosion benefits relative to conventional tillage (CT). However, the impact of ZT on drainage water quality is less known. Accordingly, two field trials were conducted during 2002-2003 and 2003-2004 to compare ZT and CT on concentration and loads of nutrients (NO3--N, SRP, TP and SO42--S) and indicator organism ( E. coli) in surface and subsurface drainage water. Zero tillage had 30-35% significantly lower concentrations of NO3--N in combined drainage water than CT. Nevertheless, NO3--N load losses were 17-40% greater under ZT than that of CT. Subsurface drainage contributed greatly to NO3--N losses. A similar trend was observed with SO42--S. However, no effect of tillage was observed on E. coli, SRP and TP concentrations in either combined or individual drainage sources. When the nutrient and bacterial contamination risks were considered, no tillage effect was observed. |
