Influence of soil pH and suitability complex on potato yield at different levels of nitrogen fertilization

In order to show the influence of soil pH and soil suitability complex on potato yield, long term experiments were carried out at different N doses (40 - 160 kg N ha⁻¹) and under different soil and climatic conditions (40 - 160 kg N ha⁻¹) in 1971 - 1990. Experiment results for each of the four soil suitability complexes were classified according to soil pH into following groups: pH in KCl 4.5; 4.6 - 5.5, 4.6 - 6.5 and 6.5. The optimum soil pH for potato production was found to dependent on the soil suitability complex.