Yield and mineral composition of sweetpotato ‘Lira’

Abstract

The present study aimed to evaluate the biomass production and mineral composition of sweetpotato plant cultivar ‘Lira’ produced in south-west Portugal, in order to obtain information for the fertilizer recommendations of this crop. The biomass and mineral contents of N, P, K, Ca, Mg, Fe, Mn, Zn, Cu and B were determined in plant fractions: vines, storage roots and absorbent roots. The production of storage roots was 542,1 g per plant. At harvest, 67 % of the dry matter was accumulated in storage roots, 27 % in vines, and 6 % in the absorbent roots. The decreasing order of nutrient accumulation by storage roots was K > N > P> Ca > Mg > Mn > Fe > Zn > B > Cu and by vines was K > N > Ca > Mg > P > Mn > Fe> Zn > B > Cu. The storage roots exported, per tonne of fresh weight, the following amounts of nutrients: 2.65 kg t^-1 of N; 0.40 kg t^-1 of P; 3.45 kg t^-1 of K; 0.26 kg t^{- 1} of Ca, 0.24 kg t^-1 of Mg, 4.42 g t^-1 of Fe; 5.71 g t^-1 of Mn; 2.70 g t^-1 of Zn; 0.96 g t^-1 of Cu and 1.33 g t^-1 of B.