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Preferential flow may enhance phosphorus transport through the soil profile and thereby increase the risks for eutrophication of watercourses. The destruction of continuous macropores by tillage and better contact between soil particles and P fertilizer, facilitated by incorporation rather than surface application, should reduce the risks of a rapid P transport from the soil surface to drain tiles. To test these hypotheses, undisturbed soil monoliths (0.295 m in diameter and 1.2 m in length) were collected at a field site with a clay soil for which preferential flow behavior is the dominant solute transport mechanism. After two years of observation, average total P loads reached 1152, 1058 and 566 g ha-1 for no-tillage, conventional tillage, and conventional tillage where the P fertilizer was incorporated, respectively. The tillage treatment had no significant effect on P losses compared to zero-tillage treatment, but the improved contact between soil particles and P fertilizer established by P fertilizer incorporation significantly reduced P loads.