versión On-line ISSN 1809-4430
FORATTO, Leticia C.; ZANINI, José R. y NATALE, William. Phosphorous content and pH in the wet bulb, with diferent frequencies of fertigation using phosphoric acid. Eng. Agríc. [online]. 2007, vol.27, n.2, pp.436-444. ISSN 1809-4430. http://dx.doi.org/10.1590/S0100-69162007000300012.
Phosphated fertilizers, such as superphosphate, triple superphosphate and monoamonium phosphate, applied throught drip irrigation can present pipe incrustations and emitters obstructions. In this research, carried out in the UNESP - São Paulo State University, Jaboticabal - Brazil, it was studied the phosphorous distribution, the influence on pH and the moisture in one Oxisoil, fertigated during one month, with five applications of phosphoric acid. Four replications and eight treatments were applied, and the treatments combined two rates of P2O5 (0 and 50 kg ha-1) and four frequencies of applications (1; 3; 5 and 7 days). The irrigation or fertigation frequency did not influence the distribution of the moisture in the wet bulb; pH of the soil until 30 cm from the drip and until 40 cm in depth was reduced, reaching value of 3.6 while the phosphorous values were higher in this same region of the bulb, exceeding 1,500 mg dm-3. These results allow indicating that the phosphoric acid can be used in localized irrigation systems, controlling soil pH, because low soil pH will be able to influence the development of the cultures and, consequently, the productivity.
Palabras clave : soil acidity; drip irrigation; incrustation.