Agronomic performance of onion cultivars as affected by phosphate fertilization

ABSTRACT Phosphorus (P) is an important nutrient for obtaining high yields and has been the one that most often limits production. The objective of this study was to evaluate the agronomic performance of onion cultivars as a function of phosphate fertilization. The experiments were installed at the Rafael Fernandes Experimental Farm, of the Federal Rural University of the Semi-Arid Region, Mossoró-RN, Brazil, from July to October 2016 and from June to October 2017. The design used was randomized blocks, in a 2 x 6 factorial scheme, with four replicates. The treatments consisted of the combination of two onion cultivars (IPA11 and Rio das Antas) and six P doses (0, 60, 120, 180, 240 and 300 kg ha-1 P2O5). The economical doses of P, associated with the maximum marketable yields of onion were estimated at 212.45 and 207.65 kg ha-1 of P2O5, respectively for the cultivars IPA 11 and Rio das Antas. In general, the cultivar Rio das Antas was more productive than IPA 11, in the two growing periods.