Selection of methods for the evaluation of the available soil boron

Abstract

With the objective of selecting the most adequate method for the determination of soil available boron, soil samples collected in the area of Jaboticabal, SP, Brazil, were used. The soils used belong to the following Great Soil Groups: “Solos Podzolizados de Lins e Marília variação Marília", "Solos Podzolizados de Lins e Marília variação Lins", "Latossolo Vermelho Escuro-fase arenosa", “Latossolo Roxo" and "Terra Roxa Estruturada". The sunflower (Helianthus annuus L.) was used as indicator plant. Soil available boron was determined by the 0.05 N HCI, 0.05 N H₂SO₄, 0.05 N CH₃ COOH, 0.1% CaCl₂ methods, and hot-water in the conventional extraction system an by a modified method. With the helps of correlation analysis between the soil extracted boron resultant from the different methods and that extracted by the plant, positive, significant values of r were obtained which did not differ from each other statistically. The hot-water modified procedure was considered to be the most adequate because it presented the lowest regression coefficient.