The objective of this work was to study the effect of phosphated and potassic
fertilization on the electrical conductivity test employed to evaluate the seeds vigor of black-oat
(Avena strigosa Schreber) cv. Comum. It was evaluated the physiological quality of the seeds
harvested from an experiment in which were studied three dosis of P2O5 (zero, 40 and 80kg/ha)
and three doses of K2O (zero, 20 and 40kg/ha), as a factorial 3x3, plus an additional treatment
(without fertilization). All plots, excepting the control, had received 50kg/ha of N fertilizer, parcelled
20kg/ha at sowing and 30kg/ha at tillering stage. The seed quality was evaluated by germination
and vigor tests (first counting of germination test and electrical conductivity) after four and 18
months of the harvest. The concentration of K, Ca, Mg and Na in the leakage solution of the seeds
were quantified in the electrical conductivity test carried out 18 months after harvest. The
concentrations of K, Ca and Mg in the seeds were evaluated before the tests of the seed quality.
The concentration of the K in the seeds and the concentrations of K, Ca, Mg and Na in the leakage
solution were increased by the effect of P x K fertilization; the high values of the electrical
conductivity resulted by those increases did not indicated lesser physiological quality of the seeds.