Boron Leaching Decreases withIncreases on Soil pH

Abstract

Management of boron fertilization depends on the magnitude of B leaching in the soil profile, which varies proportionally with the concentration of B in the soil solution, which, in turn, decreases as the soil pH increases due to the higher sorption of B on soil solid surfaces. The objective of this study was to quantify the effect of liming and rates of B applied to the soil on B leaching. The experiment was carried out in the laboratory in 2012, and treatments consisted of a factorial combination of two rates of liming (without and with lime to raise the soil pH to 6.0) and five rates of B (0, 10, 20, 50 and 100 mg kg Boron was manually mixed with the top 0.15 m of the soil. After that, every seven days for 15 weeks, 300 mL of distilled water were added to the top of each column. In the percolated solution, both the volume and concentration of B were measured. Leaching of B decreased with increased soil pH and, averaged across the B rates applied, was 58 % higher from unlimed (pH 4.6) than from limed (pH 6.6) samples as a result of the increase in B sorption with higher soil pH. In spite of its high vertical mobility, the residual effect of B was high in this oxisol, mainly in the limed samples where 80 % of B applied at the two highest rates remained in the soil, even after 15 water percolations.Total recovery of applied B, including leached B plus B extracted from the soil after all percolations, was less than 50 %, showing that not all sorbed B was quantified by the hot water extraction method.

Physiological quality and grain production of Phaseolus vulgaris (cv. BRS Pérola) using boron (B) application under irrigatation system

“…Boron occurs in the soil solution mainly as H 3 BO 3 , which is the predominant form in agricultural soils, showing pH ranging from 5.5 up to 6 (Malavolta, 2006). The main factor driving B behavior is soil pH (Sá and Ernani, 2016), being strongly adsorbed by Fe and Al oxides in pH ranging from 6 to 9. The highest B availability is observed in pH from 5 up to 7 (Malavolta, 2006).…”

Grain yield of Phaseolus vulgaris in a function of application of boron in soil

“…Its availability is mainly influenced by soil pH values (Sá and Ernani, 2016), soil organic matter (Lima et al, 2007), mobility in the soil profile (leaching) due to the high intensity of rainfalls (Prado, 2008), soil parental material, topography and soil type and use (Zhu et al, 2016).…”

Influência da adubação bórica na cultura do feijoeiro

“…No solo o B atua como um ânion, sua quimissorção aumenta com a acidez do solo. Em solos cujo pH está abaixo de 7,0, o boro na forma de H3BO3 é altamente suscetível a lixiviação (SÁ et al, 2016). O ácido bórico é considerado como muito fraco e atua como ácido de Lewis, que para a formação do ânion borato necessita aceitar um hidróxido (GOLDBERG, 1997).…”

“…Geralmente apenas uma fração do B aplicado no solo permanece na solução do solo, disponível para as plantas absorverem, consequentemente a outra fração sofre o processo de lixiviação. Alguns atributos do solo como a granulometria e a composição mineralógica podem afetar a disponibilidade de B, neste sentido os solos arenosos são mais suscetíveis a lixiviação do que os argilosos (SÁ et al, 2016).…”