Accuracy of methods to estimate potential acidity and lime requirement in soils of west region of Santa Catarina

• Published in: Ciência rural 2018-01, Vol.48 (4)
• Main Authors: Predebon, Rodrigo, Gatiboni, Luciano Colpo, Mumbach, Gilmar Luiz, Schmitt, Djalma Eugenio, Dall’Orsoletta, Daniel João, Brunetto, Gustavo
• Format: Article
• Language: English
• Subjects: Accuracy; Acetic acid; Acidity; AGRONOMY; base saturation; Buffers; Calcium; Calcium acetate; Calcium buffering; Hydrogen; Lime; Liming; pH effects; SMP; Soil lime; Soils
• ISSN: 0103-8478; 1678-4596; 1678-4596
• DOI: 10.1590/0103-8478cr20160935

The objective of this study was to compare two methods of evaluation of potencial acidity (H+Al) and two methods to estimate liming requirement (LR) for soils from the west region of Santa Catarina State, Brazil. Fourteen soils were incubated with 7 lime rates for 120 days, obtaining the real values of H+Al at pH 7.0 and LR. These values were used as reference to evaluate the accuracy of two H+Al estimating methods: SMP buffer and calcium acetate at pH 7.0, and to evaluate the accuracy of two LR methods: base saturation (BS) and SMP index. On average, H+Al was underestimated in 6 and 40% by SMP and calcium acetate methods, respectively, especially in soils with high buffer capacity. The LR was underestimated in 20 and 30% by SMP index and BS, respectively. The SMP Index showed a better LR estimative than BS, especially in soils with high buffer capacity. RESUMO: O estudo objetivou comparar dois métodos de avaliação de acidez potencial (H+Al) e de estimativa da necessidade de calagem (NC) para solos da região Oeste de Santa Catarina (SC). Quatorze solos foram incubados com 7 doses de calcário durante 120 dias, obtendo-se ao final os valores reais de H+Al a pH 7,0 e a NC dos solos. Esses valores serviram de referência para avaliar a exatidão dos métodos de estimativa do H+Al: tampão SMP e acetato de cálcio a pH 7,0 e a exatidão dos métodos de estimativa da NC: índice SMP e saturação por bases (V%). Em média, o H+Al foi subestimado em 6 e 40% pelos métodos SMP e acetato de cálcio, respectivamente, sendo mais problemático nos solos de maior tamponamento. Já a NC foi subestimada em 20 e 30% pelo Índice SMP e V%, respectivamente. O índice SMP estimou melhor a NC que o método V%, principalmente em solos de maior tamponamento.