Effects of nitrogen fertilization of grapefruit trees on soil acidification and nutrient availability in a Riviera fine sand

• Published in: Plant and soil 1999-09, Vol.206 (1), p.11-19
• Main Authors: He, Z.L. (Florida Univ., Fort Pierce, FL (USA). Indian River Research and Education Center), Alva, A.K, Calvert, D.V, Li, Y.C, Banks, D.J
• Format: Article
• Language: English
• Subjects: ABONOS NITROGENADOS; Acid soils; Acidic soils; ACIDIFICACION; ACIDIFICATION; Agronomy. Soil science and plant productions; Availability; Biological and medical sciences; Chemical, physicochemical, biochemical and biological properties; CITRUS PARADISI; Controlled release; DISPONIBILIDAD DE NUTRIENTES; DISPONIBILITE D'ELEMENT NUTRITIF; ENGRAIS AZOTE; Fertilization; Fertilizers; Fruit trees; Fruits; Fundamental and applied biological sciences. Psychology; Granular materials; Grapefruit; LEACHING; Leaves; LESSIVAGE DU SOL; LIXIVIACION; Manganese; Mineral components. Ionic and exchange properties; Nitrogen; NITROGEN FERTILIZERS; NUTRIENT AVAILABILITY; Nutrient loss; Physics, chemistry, biochemistry and biology of agricultural and forest soils; Sand; Sand soils; SANDY SOILS; Soil acidification; Soil chemistry; Soil pH; Soil pollution; Soil science; Soil sciences; Soil solution; Soil water; Soils; SOL SABLEUX; SUELO ARENOSO; Trees; Zinc
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1023/A:1004364805789

Nitrogen (N) fertilizer applied in the NH₄⁺ form results in some degree of soil acidification, which could influence nutrient availability to plants and nutrient losses through leaching. Effects of various N rates (0 - 168 kg N ha⁻¹ yr⁻¹) on soil acidification and nutrient availability were investigated in a Riviera fine sand with 26-year-old white Marsh grapefruit (Citrus paradisi MacFadyen) trees. Soil pH significantly decreased with increasing NH₄-N rates. Application of 112 kg N ha⁻¹ yr⁻¹ for four years decreased the pH by 0.7 to 1.7 unit. Soil acidification was greater when the NH₄⁺ form of N fertilizer was applied as dry soluble granular material compared to fertigation or controlled release forms. The marked effect of NH₄-N fertilization on the pH of the Riviera fine sand was due to its low buffering capacity. Soil acidification increased the concentration of extractable Fe and P but decreased that of K, Zn and Mn. Soil pH was positively correlated with concentration of Ca, but negatively with concentrations of Fe, Mn and Zn in six-month-old spring flush leaves of the grapefruit trees. Leaf P concentrations, however, were poorly correlated with soil pH. This study also demonstrated an increase in leaching of P and K below the grapefruit trees rootzone with a decrease in soil pH.