Sequential Extraction of Phosphorus by Mehlich-1 and Ion Exchange Resin From B Horizons of Ferric and Perferric Latosols (Oxisols)

Abstract

In general, Latosols have low levels of available P, however, the influence of the parent material seems to be decisive in defining the pool and predominant form of P in these soils. This study evaluated P availability by extraction with Mehlich-1 (M-1) and Ion Exchange Resin (IER), from samples of B horizons of Ferric and Perferric Latosols developed from different parent materials. To this end, in addition to the physical and chemical characterization of soils, 10 sequential extractions were performed with M-1 and IER from samples of B horizons (depth between 0.8 and 1.0 m). Total contents of Ca, P, Fe, Al, and Ti were determined after digestion with nitric, hydrofluoric and perchloric acids. The effects of sequential P extractions on Fe oxides were also evaluated from the analyses of dithionite-citrate-bicarbonate and ammonium acid oxalate. The high similarity between contents of P accumulated after sequential extractions with M-1 and IER in soils developed on tuffite indicated a predominance of P-Ca. Higher contents of P after a single IER extraction show greater efficiency in P removal from highly weathered soils, as from the Latosols studied here. The P contents also show the high sensitivity of extractant M-1 in highly buffered soils. Furthermore, a single extraction with extractant M-1 or IER is not sufficient to estimate the amount of labile P in these soils.

Fertilización organomineral y NPK en el cultivo maíz (Zea mays L.)

“…Todavia, em sistema de semeadura direto há maior eficiência de aproveitamento do P pelas plantas, sendo isso atribuído ao menor contato entre fertilizante e partículas do solo, promovido pela ausência de revolvimento e a presença de resíduos vegetais, ou palhada sob a superfície do solo que favorece a retenção de umidade (Rosim et al, 2012). Segundo Camêlo et al (2015) o que melhora a taxa de difusão do fósforo até as raízes, sendo que em solos de clima tropical, acredita-se que os ácidos orgânicos competem pelos sítios de adsorção de P, podendo aumentar a sua disponibilidade devido ao recobrimento dos óxidos de Fe e de Al. No entanto, Almeida et al (2016) afirmam que vale ressaltar que, neste caso, a presença de matéria orgânica reduz a adsorção de P., sendo essas reduções mesmo que em pequenas proporções, podem aumentar a eficiência agronômica dos fertilizantes fosfatados em solos altamente intemperizados, possibilitando maior absorção de P pelas culturas.…”

Cellulose Acetate Film and Layered Double Hydroxide as Determination Method of Available Phosphorus in the Soil

“…In Brazil, the Mehlich-1 (M-1) is the more frequently used extractor, with thousands of researches that validate its application as appropriate extractor of available P for the soil [2][3][4]. This extractant presents unsatisfactory response for soils with high contents of P-Ca, naturally occurring in soils less weathered where this form of P predominates or even in those more weathered that received natural phosphate more recently [5][6][7]. To get around this problem, even if partially, ion exchange resin was developed by Amer et al [8].…”

Eficiência De Fertilizante Fosfatado Protegido Na Cultura Do Milho

“…Além disso, em solos de clima tropical, acredita-se que os ácidos orgânicos competem pelos sítios de adsorção de P, podendo aumentar a sua disponibilidade devido ao recobrimento dos óxidos de Fe e de Al (CAMÊLO et al, 2015). Vale ressaltar que, neste caso, a presença de matéria orgânica apenas reduz a adsorção de P. No entanto, essas reduções, mesmo que em pequenas proporções, podem aumentar a eficiência agronômica dos fertilizantes fosfatados em solos altamente intemperizados e com isso possibilitar maior absorção de P pelas culturas.…”