SULFUR APPLICATION STAGE ON PRODUCTIVITY OF ONION BULBS (Allium cepa L.)

Abstract

Sulfur (S) is necessary for the cultivation of onions (Allium cepa L.). In Brazil, studies related to the fertilization of onion crops are scarce. The objective of this research was to evaluate the effect of application periods of S on agronomic characteristics in two onion cultivars. The hypothesis was that the application of S increases productivity and affects the quality of onion bulbs. The experimental design was randomized blocks with four replicates for a triple factorial arrangement (5x2x2), five stages of application of S (control, transplanting, six to seven leaves, bulb differentiation and full bulbing), two onion cultivars (Dulciana® and Vulkana®) and two years of cultivation. The characteristics evaluated were productivity (Mg ha-1), average mass of the bulb (g), length and diameter of the bulb (mm), shape of the bulb, number of leaves and classification of the bulb. The application of S affects the productivity and quality of onion bulbs. Transplanting is the most recommended stage for the application of S, since it positively influences the onion crop in all the evaluated characteristics. The application of S did not affect the shape of the bulb in the different stages evaluated. The best productive yield of the onion varieties was obtained with 59.07 Mg ha-1 of sulfur in Dulciana® and with 73.34 Mg ha-1 in Vulkana® .