Phosphorus Extraction with Soil Test Methods Affected by Soil P Sorption Capacity

Abstract

The aim of this study was to evaluate the phosphorus (P) extraction ability of the methods Mehlich 1 (M-1), Mehlich 3 (M-3), anion exchange resin in strips (AER-ST), and anion exchange resin in spheres (AER-SP), as a function of clay content, P rates, and incubation time. Experimental units were built with 20%, 40%, 60%, and 80% of clay and five different phosphorus rates as follows: 0, 100, 200, 400, and 600 mg P kg −1 , with subsequent incubation for 0, 30, and 90 days. After that, the samples were subjected to the analysis of extractable P using the M-1, M-3, AER-ST, and AER-SP extractors. All P extraction methods evaluated were sensitive to clay content and to the amount of added P. The input of P increased the recovery of this nutrient by all extractors, but this was less effective when the clay content of the soil was increased. In general, the ability of phosphorus extraction from the soil followed the order: M-1 > AER-SP > M-3 > AER-ST. The longer contact time of P with the soil, lower is the extracted P content, regardless of the extraction method, this being more evident in clayey soils. All extraction methods tested are sensitive to clay content, incubation time, and to the P concentration applied.

Extractor efficiency and critical phosphorus levels for establishing pasture in Amazonas

“…Studies with extractors in soils with similar characteristics to Amazon soils show divergent results. Novais et al (2015) found a decrease in P extraction by Mehlich-1 in clay soils, while an opposite result was found by Mumbach et al (2020), in which greater extractions were obtained by Mehlich-1. In a study by Arruda et al (2015), the resin was more efficient than Mehlich-1 in evaluating the P content in the soil, and Mumbach et al (2018) identified that Mehlich-3 and resin extractions were 11 to 12% higher than Mehlich-1 extractions.…”

“…Mehlich-1 decreases its performance in high organic matter levels (Kabala et al, 2018), corroborating the results found in this study. Organic matter can influence the dynamics of P adsorption in soil in different ways, thus contributing to the predominance of amorphous minerals and having greater reactivity with the soil or reducing adsorption through the release of humic compounds which block adsorption sites (Mumbach et al, 2020).…”

“…The acetic acid solution is used to extract P, promoting dissolution of Ca phosphates, and the addition of ammonium fluoride releases more P from the phosphates bound to Al through formation of Al-F complexes (Wuenscher et al, 2015). High applicability, correlation with other P analysis methods, and a high correlation of P extractions with crop yield are the most striking characteristics among the benefits of this method which that determine its use in the United States of America (USA), Canada (Kabala et al, 2018) and Southern Brazil (Mumbach et al, 2020).…”

Impact of Humic Acids on Phosphorus Retention and Transport

“…The impacts of HA on P were various in previous studies, because of different soil properties, forms of nutrient, and even the extraction methods (Mumbach et al 2020;Zavaschi et al 2020). For example, Fu et al verified higher P adsorption onto goethite was achieved with a lower pH either with the presence or absence of HA (Fu et al 2013).…”

Dinâmica da atividade da fosfatase ácida como indicador da disponibilidade de fósforo em diferentes texturas de solo na cultura da soja

“…A resina trocadora de ânions apresenta maior sensibilidade na quantificação da disponibilidade de nutrientes no solo, pois apresenta melhor relação com os valores absorvido pelas plantas, sendo considerada de boa precisão ( VAN RAIJ et al, 2009). Portanto, o teor de argila deve ser levado em consideração ao avaliar a disponibilidade de P no solo (MUMBACH et al, 2020). Nessa pesquisa, de acordo com Seixas et al, (2020), os valores de P extraídos pela resina trocadora de ânions (Figura 4) são considerados como alto e muito alto no solo, exceto para o tipo de textura do solo LAd no nível severo, com teor de P no solo considerado como baixo.…”