Yield and post-harvest conservation of onion bulbs using doses of nitrogen and potassium

This study was carried out from March to November 2001, in Petrolina, Pernambuco State, Brazil, to evaluate the influence of nitrogen and potassium levels applied through fertirrigation, on yield and post-harvest quality of onion bulbs. Cultivar Franciscana IPA-10 was used in a randomized complete block design, in a 4 x 3 factorial arrangement, with four nitrogen levels (0; 60; 120 and 180 kg ha(-1)) and three potassium levels (0; 90 and 180 kg ha(-1) of K2O) with three replications. The applied levels of nitrogen showed linear effects on the commercial yield independent of the potassium fertilization. The non-commercial yield (calls) showed linear reductions in the three potassium levels, with the increase in nitrogen levels. With the increase of applied nitrogen levels a linear effect on the fresh mass of the bulbs was observed. There were no significant effects of nitrogen and potassium application on the mass loss of the bulbs at 40 and 80 days after cure.