Soil and crop responses to zero and reduced ground pressure traffic systems and to a conventional traffic system were compared over five seasons in an arable rotation of potatoes ( Solanum tuberosum L.), spring and winter barley ( Hordeum vulgaris L.) and spring oil-seed rape ( Brassica napus L.). Fertiliser reductions of 20% or 40%, as well as the full recommended rates, were tested in all crops for the three traffic systems. Machinery in the experimental zero traffic system allowed crops to be grown in 2.4 m wide, traffic-free cropped strips with all wheels running on uncropped, permanent wheel tracks. The tractor wheels in the reduced ground pressure traffic system had all tyres replaced by wide-section, low-inflation pressure tyres which ran on the cropped areas. Yields of winter and spring barley over three seasons were significantly greater for the zero traffic system than for the reduced ground pressure and conventional traffic systems, with 92% and 89% of this variability, respectively, explained by differences in the mean soil cone resistances between 0 mm and 270 mm depths. In the spring oil-seed rape crop over two seasons, 98% of the variability in yield was explained by soil vane shear strength and mean soil temperature. The percentage marketable yield of potatoes was significantly greater for the zero system by 3.5%, on average, than for the other two systems, although there was no effect of traffic on total yield of potatoes. In comparison with crops grown in the reduced ground pressure and conventional traffic systems with the full recommended N fertiliser rate, the zero system could maintain the mean yield and either low barley grain N content or low glucosinolate and high oil rapeseed contents with fertiliser reductions of 20% in the winter barley, and at least 30% in both the spring barley and spring oil-seed rape crops. Fertiliser reductions of 15% could be made using the zero traffic system in the potato crop, but it may be more economical to reduce the planted area at the full fertiliser rate because of greater cultivation energy savings.