Effects of split-applied nitrogen fertigation on sunflower (Helianthus annuus)

Abstract

The influence of split nitrogen applied via fertigation on the culture of early-cycle BRS 323 sunflower was evaluated. The experiment was conducted at the Federal University of Ceará, Brazil, in a randomized block design, with five treatments and five repetitions. The treatments corresponded to the recommended N doses: 50; 25; 12.5; 6.25 and 3.2 kg ha-1. At 55 days after sowing, the following variables were evaluated: thousand seed mass, productivity, seed oil content, head dry mass, leaf dry mass and leaf area as a function of the number of N applications via fertigation. Yield, seed oil content and head dry mass were influenced by N treatments at the 5% level, while thousand seed mass, leaf dry mass and leaf area were significant at 1%. The application of parceled nitrogen fertilization by fertigation can be recommended to sunflower producers, because it can increase the production of this crop, since the parceled application of N positively influences the behavior of the following variables: DMLeaf; Leaf area; 1000SM, PROD, SOC and MS Head.