Hardening and Stability of Plinthic Materials of the Araguaia River Floodplain under Different Drying Treatments

Leonardo Santos Collier,Angélica Pires Batista Martins,Deyvid Diego Carvalho Maranhão,Glenio Guimarães Santos,Virlei Álvaro de Oliveira

doi:10.1590/18069657rbcs20170190

Abstract

ABSTRACT Plinthite and petroplinthite occur frequently in Brazilian soils, but there is little information on the behavior of these materials. The aim of the present study was to assess the effect of different drying periods on the hardening and stability of plinthic materials of soils in the floodplain of the Araguaia River and the Joao Leite stream in Goias. Soil samples were collected, with the aid of 0.10 m high and 0.15 m diameter PVC cylinders, directly from the plinthic [...]

Highlights

Plinthite is a formation consisting of a mixture of clay material that is low in organic carbon and rich in iron, or iron and aluminum, with grains of quartz and other minerals (Santos et al, 2013)
Plinthite genesis is associated with seasonal changes in groundwater level, as follows: a high groundwater level results in iron content reduction, mobilization, transport, and concentration; low groundwater levels result in irreversible hardening of plinthite, forming nodules or ferruginous concretions called petroplinthites (Moreira and Brazil has extensive areas of soils prone to the formation of plinthites and petroplinthites (Anjos et al, 1995; Batista and Santos, 1995)
In P6, only soil matrix subsamples were collected, which had a reddish colored material characterized as plinthite during soil sample collection in the field, but plinthite could not be distinguished from the soil matrix by hardness

Summary

Introduction

Plinthite is a formation consisting of a mixture of clay material that is low in organic carbon and rich in iron, or iron and aluminum, with grains of quartz and other minerals (Santos et al, 2013). Plinthite genesis is associated with seasonal changes in groundwater level, as follows: a high groundwater level results in iron content reduction, mobilization, transport, and concentration; low groundwater levels result in irreversible hardening of plinthite, forming nodules or ferruginous concretions called petroplinthites (Moreira and Oliveira, 2008). Brazil has extensive areas of soils prone to the formation of plinthites and petroplinthites (Anjos et al, 1995; Batista and Santos, 1995). Seasonal groundwater variations make agricultural management of plinthic soils quite complex, requiring control of their water dynamics (IBGE, 2015). Artificial drainage is required in soils under intensive use. Excessive lowering of groundwater leads to plinthite hardening (Martins et al, 2006)

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