The nitrogen response of potato (Solanum tuberosum L.) in the field: nitrogen uptake and yield, harvest index and nitrogen concentration

Summary The response of potato to different rates of nitrogen supply ranging from 0–40 g m⁻² N was studied in five field experiments near Wageningen. NL (52⁰ North). In total two late potato cultivars and two sites were used during successive seasons. The results are summarized in a set of regression equations separately for total crop and tubers. The relation between nitrogen taken up (g m⁻²) in the total crop and total dry matter production (g m⁻²) could be described with the exponential equation: 1942–1900 * 0.93^X (r²=0.953, n=62). Nitrogen concentrations in the dry matter increased linearly with nitrogen uptake. Harvest indices for dry matter and nitrogen tended to decline with increase in N uptake. Cultivars differed only in the effect on N on tuber dry matter concentration. The relation between nitrogen uptake and nitrogen supply could be fitted with quadratic regression models. but coefficients were influenced by site and season.