Multivariate analysis of relationship between potato (Solanum tuberosum L.) yield, amount of applied elements, their concentrations in tubers and uptake in a long-term fertilizer experiment

The aim of this study was to investigate how potato yield, the concentrations of elements (N, P, K, Ca, Mg, S, As, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) in tubers and their uptake are affected by mineral N, P and K fertilizers, straw and pig slurry application.Potatoes were collected in 2008 from the Ruzyně Fertilizer Experiment (RFE, the Czech Republic, 24 fertilizer treatments), which was established on a permanent arable field (Illimerized Luvisol) in 1955. Fifty-three years of fertilizer application have resulted in highly contrasting levels of P and K availability in the different treatments. A plant available (Mehlich III) soil P concentration below 30 mg kg−1 and a K concentration below 150 mg kg−1 were not adequate for satisfactory tuber production. No positive effect of long-term straw application on tuber yield was recorded. The optimal application rate of mineral fertilizers resulting in a tuber yield above 30 t ha−1 was 140 kg N ha−1, 63 kg P ha−1 and 186 kg K ha−1. The highest environmentally acceptable N application rate for potatoes was 120 kg N ha−1, applied in the form of mineral fertilizer. Substantially higher production efficiency was recorded for mineral N, P and K fertilizers than for pig slurry. The concentrations of As, Cd, Cr, Cu, Fe, Mn, Pb and Zn in tubers were not significantly affected by fertilizer treatment although pig slurry supplied substantially higher amounts of Cu and Zn to the soil than were taken up by the tubers. The concentration of Pb exceeded the Czech legislation DM limit (0.61 mg kg−1) in 83% of samples, but there was no significant effect of fertilizer treatment. Therefore normal cropping practices do not significantly increase the concentrations of trace elements in potatoes.