Sunflower performance as a function of phosphate fertilization in semiarid conditions

ABSTRACT. The objective of this work was to evaluate the response of sunflower cultivars submitted to increasing levels of phosphate fertilization in two crops. The experimental design was a randomized complete block design with four replicates in subdivided plots, where five doses of simple superphosphate (0, 50, 100, 150, and 200 kg ha-1 P2O5) were allocated to the plots and three sunflower cultivars (Aguará 06, Altis 99, and Embrapa 122-V2000) were assigned to the subplots. The variables evaluated were the P content in the diagnostic leaf, number of achenes per capitulum, achene yield (kg ha-1), oil content (%) and oil yield. The phosphorus doses increased the components of production. The dose that provided the best sunflower performance varied for the different cultivars. Among the doses studied, fertilization with 100 kg ha-1 P2O5 in the 2016 agricultural crop and 150 kg ha-1 P2O5 in the 2017 agricultural crop provided the best conditions for sunflower cultivation. The cultivar Aguará 06 produced more achenes and oil than the other cultivars analyzed in the agricultural crops.