The determination of nutrient absorption during the growth cycle is essential to determine the periods in which these elements are most required and the correct amounts that should be provided for potato, but for most cultivars used in Brazil the information is extremely scarce. The objective of this study was to evaluate absorption and exportation of the macronutrients N, P, K, Ca, Mg, and S by the potato cultivars Ágata, Asterix, Atlantic, Markies, and Mondial. The experiment was conducted in Itaí, São Paulo State, Brazil, in the 2008 winter growing season on an Oxisol. Plots consisted of the five potato cultivars and subplots of sampling times (at planting and every seven days after emergence). The cultivars Mondial and Asterix, the most productive, absorbed highest average macronutrient quantities per hectare (116 kg N, 18 kg P, 243 kg K, 50 kg Ca, and 13 kg Mg), while Ágata, Atlantic and Markies absorbed smaller average amounts (92, 14, 178, 35, and 9 kg ha-1, respectively). The stage of highest macronutrient demand by the cultivars was during initial tuber bulking (42 to 70 days after planting). Macronutrient exportation was not directly related to tuber yield, since it was not the most productive cultivar (Mondial) that exported the highest macronutrient amounts. Asterix exported higher N, P, K and Mg amounts (88, 15, 220 and 8 kg ha-1, respectively), while the lowest quantities were exported by cultivar Atlantic (48 kg ha-1 N, 10 kg ha-1 P, 143 kg ha-1 K, and 5 kg ha-1 Mg). The wide variation in absorption among cultivars, especially of K and N, indicate the need of a differentiated fertilization management.
Solanum tuberosum; mineral nutrition; absorption curves; absorption rates; nutrient accumulation
