No presente trabalho foi feito um levantamento dos teores de manganês total e trocável no horizonte Ap de alguns grandes grupos do Estado de são Paulo e séries do Município de Piracicaba. Procurou-se também correlacionar o comportamento do manganês total e trocável com outras características dos solos estudados. Considerou-se como manganês total o digerido numa mistura de ácido nítrico e sulfúrico. O trocável foi representado pelo extraído com nitrato de potássio N. No horizonte Ap dos solos estudados, os resultados obtidos, analisados e interpretados permitiram as seguintes conclusões: a - Os teores de manganês total dos solos apresentaram uma variação de 0,315 a 7,988 e.mg/100 g de solo. b - Na avaliação do manganês trocável, extraído pelo nitrato de potássio N, as quantidades variaram desde traços a 0,165 e.mg/ 100 g de solo. e - Os solos originários de rochas eruptivas básicas que correspondem aos Grandes Grupos Latosol Roxo e Terra Roxa Estruturada, possuem teores mais elevados de manganês total. d - A relação entre o manganês trocável e total exibiu variações de 0,67 a 48% e - Os teores de manganês total dos solos correlacionaram em ordem decrescente com Fe₂O₃ >argila > pH. f - O pH mostrou influenciar na disponibilidade do manganês trocável, segundo uma correlação quadrática. g - Ao pH de aproximadamente 5,1 o manganês trocável apresentou uma maior disponibilidade.

This work reports a survey of the total and exchangeable manganese oontent in the Ap horizon of some Great Soil Groups of the State of são Paulo and soil series occurring in the Piracicaba Municipality. An attempt was made to correlate total and exchangeable manganese with other characteristics of the soils studied. Total manganese was considered as that digested in a mixture of nitric and sulfuric acid. Exchangeable manganese was re presented by that extracted by 1 N potassium nitrate. The results obtaincd were statistically analyzed. Their interpretation led to the following conclusions: a - Total manganese content varied from 0,135 to 7.988 meg/100 gof soil. b - Exchangeable manganese varied from traces to 0.165 meg/100 g of soil. This work reports a survey of the total and exchangeable manganese oontent in the Ap horizon of some Great Soil Groups of the State of são Paulo and soil series occurring in the Piracicaba Municipality. An attempt was made to correlate total and exchangeable manganese with other characteristics of the soils studied. Total manganese was considered as that digested in a mixture of nitric and sulfuric acid. Exchangeable manganese was re presented by that extracted by 1 N potassium nitrate. The results obtaincd were statistically analyzed. Their interpretation led to the following conclusions: a - Total manganese content varied from 0,135 to 7.988 meg/100 gof soil. b - Exchangeable manganese varied from traces to 0.165 meg/100 g of soil. This work reports a survey of the total and exchangeable manganese oontent in the Ap horizon of some Great Soil Groups of the State of são Paulo and soil series occurring in the Piracicaba Municipality. An attempt was made to correlate total and exchangeable manganese with other characteristics of the soils studied. Total manganese was considered as that digested in a mixture of nitric and sulfuric acid. Exchangeable manganese was re presented by that extracted by 1 N potassium nitrate. The results obtaincd were statistically analyzed. Their interpretation led to the following conclusions: a - Total manganese content varied from 0,135 to 7.988 meg/100 gof soil. b - Exchangeable manganese varied from traces to 0.165 meg/100 g of soil. e - Soil derived from basic eruptive parent material belonging to the Great Soil Groups ?Terra Roxa Estruturada? and ?Roxo? Latosol had a higher content on total manganese. d - The ratio between exchangeable and total manganese varied between 0,67% and 48%. e - Total manganese content correlated in decreasing order Fe₂O₃ , clay and soil pH. with f - Soil pH affedted exchangeable manganese availability following a quadratic correlation. g - Maximum availability was found to ocur at pH of approximately 5.1.