Use of blood residue as alternative source of phosphorus in sunflower (Helianthus annuus L.) cultivation

The aim of this work was to increase the aerial part, biometry, and yield of achenes from sunflower plants on the effect of increasing doses of blood residue, as an alternative source of phosphorus (P), in a clayey-textured red Oxisol. The experimental design used was randomized blocks, with six treatments and four replications. The treatments consisted of five doses of blood residue (0, 6, 12, 24 and 48m(3) ha(-1)) and a control treatment that received phosphate chemical fertilization, 80kg ha(-1) of P2O5. The increasing doses of blood residue and chemical fertilization do not show disproportionality for P concentration in soil, leaf, plant height (PH), stem diameter (SD), chapter diameter (CD) and achene production. The analysis of the principal component (PC) revealed that the first PC presents the greatest accumulated variation (74%). Based on the first PC, the dose of 12m(-3) ha(-1) has greater influence for PH, SC, and CD. Due to the greater influence on the biometric characteristics of sunflower plants, the blood residue (12m(-3) ha(-1) = 98.4kg P ha(-1)), can be used as an alternative source of phosphorus for the cultivation of sunflower in clayey oxisols.