Quality of seedbed and ridges for potatoes as affected by low ground pressure, compared with normal and zero ground pressure

The influence of ground pressure by field traffic on soil structure and on growth and yield of potatoes, in a crop rotation of onions, potatoes, winterwheat and sugarbeet, was investigated in a “low ground pressure” experiment from 1985 to 1989 on the experimental husbandry farm “De Oostwaardhoeve”. Low ground pressures (L) of 50–100 kPa, with relatively wide tires, were compared with conventional (high) ground pressures (H) of 100–300 kPa with relatively narrow tires, and with zero ground pressure (Z) on inner ridges of beds four rows wide. The quality (amount and crumbling) of the loose soil in the seedbed, in the ridges and after harvesting of the potatoes, was investigated. With a decrease in ground pressure from H to L to Z, the amount of dry loose soil in the ridges increased from 93.6 kg m^?2 to 95.1 kg m^?2 and to 99.9 kg m^?2, the mean weighed diameter decreased from 6.0 mm to 5.4 mm and to 4.7 mm and the total increase yield from 57.1 t ha ^?1 to 59.4 t ha^?1 and to 62.9 t ha^?1, respectively. Differences in amount and crumbling of the loose soil and yield were larger between and zero ground pressure than between low and conventional (high) ground pressure plots.