Abstract

ZAMUDIO-GONZALEZ, B. et al. Vertical Movement of Phosphorous in Sandy Soils with Fertirrigation and Use of Amendments. Terra Latinoam [online]. 2011, vol.29, n.3, pp.249-258. ISSN 2395-8030.

In triplicate vertical columns in the laboratory, packed with calcareous alluvial soil and subsoil collected from fields cultivated with vineyards in the northwestern of Mexico, the displacement of five sources of phosphorus (P) fertilizer were evaluated by drip fertigation associated with well water untreated and treated with sulfuric acid and agricultural gypsum. The tested fertilizer dose of 50 mg L-1 P in solution were: phosphoric acid (H3PO4), monoamonic phosphate NH4H2PO4 (11-52-0), liquid poly ammonium phosphate (10-34-0), Poly- Feed® (15-31-15) and Fertigro® (liquid phosphoric fertilizer mixed with humic substances). It was considered two simulated irrigation processes in columns of 0.7 m depth: first, porous media were saturated with and without treated water and no fertilizers to obtain five wash fractions to measure pH and salts changes; and a second process, fertigation with five sources for measuring P leached and retained into seven sections of 0.1 m of the columns. The results obtained were: first, at the end of washing process, drainage fractions accused pH values higher than 8.5, even with amended water (Am), a favorable condition to the P precipitation; second, there were no leachates soluble of P when supplying the five fertilizer sources; third, the treated water with agricultural gypsum and sulfuric acid, reduced the availability of P in soil columns by 40% and in the subsoil by 57%; fourth, the availability of P increased when the columns were watered with alkaline water in both porous media was obtained with H3PO4, followed by NH4H2PO4 and by liquid poly-ammonium phosphate.

Keywords : leaching; drip irrigation; water quality; and porous media.