ABSTRACT
The dynamics of biomass accumulation during the growing period, the yield of leafy stalks and tubers, and the nutrient concentration and nutrient uptake of the yield were investigated for two Jerusalem artichoke varieties (Tápiói Korai and Tápiói Sima) in a field experiment involving mineral fertilisation. Considerable differences were observed between the dynamics of leafy stalk and tuber development in Tápiói Korai which has a short vegetation period and Tápiói Sima where the vegetation period is long. The maximum dry matter ratio between the tuber yield and the leafy stalk yield was 1:1 for Tápiói Korai and 1:4.5 for Tápiói Sima. During the period when the maximum aboveground biomass developed in Tápiói Korai, 100 kg.ha-1 N and P fertiliser resulted in the highest leafy stalk yield (38.34 t.ha-1), while for Tápiói Sima, which developed a much greater leafy stalk mass, the highest aboveground biomass yield (78-80 t.ha-1) was given in response to 200 kg.ha-1 N supplemented by P and K fertiliser. Both artichoke varieties produced the great-est tuber yield at a N rate of 200 kg.ha-1, supplemented with P and K fertiliser. The nutrient concentration in the leafy stalks was highest on the 85th day of the vegetation period, prior to intensive dry matter accumulation in the leafy stalks and before tuber formation began. In both varieties the maximum nutrient uptake was recorded on the 155th day. Great differences were observed between the varieties in terms of specific nutrient uptake. For a tuber yield of 10 t, together with the corresponding leafy stalk yield, the specific nutrient uptake of the Tápiói Korai variety amounted to 48 kg N, 10 kg P, 83 kg K, 30 kg Ca and 10 kg Mg, while for Tápiói Sima these figures were 162 kg N, 30 kg P, 300 kg K, 84 kg Ca and 45 kg Mg.