SOILS, SEC 2 • GLOBAL CHANGE, ENVIRON RISK ASSESS, SUSTAINABLE LAND USE • RESEARCH ARTICLE Use of geophysical methods for the study of sandy soils under Campinarana at the National Park of Viruá, Roraima state, Brazilian Amazonia Bruno Araujo Furtado de Mendonça & Elpídio Inácio Fernandes Filho & Carlos Ernesto Gonçalves Reynaud Schaefer & Anôr Fiorini de Carvalho & José Frutuoso do Vale Jr. & Guilherme Resende Corrêa Received: 28 February 2013 /Accepted: 8 November 2013 /Published online: 9 January 2014 # Springer-Verlag Berlin Heidelberg 2013 Abstract Purpose The vegetation of the Campinaranas occurs in humid areas with hydromorphic sandy soils at the Amazon region. Thus, the determination and in situ monitoring of moisture content in Campinarana soils, besides the detection of subsurface layers are key measures for studying these soil–vegetation systems. Also, the application of ground penetrating radar (GPR) in deep sandy sedimentary sequence of Amazonia is a promising tool to en- hance the knowledge on depositional and soil formation features. Materials and methods We studied representative soils of the Campinaranas at the National Park of Viruá, state of Roraima (Brazilian Amazonia), through the use of geophysical methods (soil moisture sensors and GPR). The study was applied in four sandy soils. Besides chemical and physical analysis of soils, soil moisture sensors were installed for monitoring during an entire hydrological year (2010/2011), and performed the calibration of sensors , coupled with imag- ing of the soil along transects with GPR. Results and discussion As a result of calibration of the soil moisture sensors we obtained a general equation with an R 2 greater than 0.9. There is an influence of soil moisture content and soil temperature in the distribution of vegetation types in Campinaranas. The use of GPR identified some determinants characteristics in these soils for the differentiating the Campinaranas, represented by spodic and C horizons. Conclusions The spodic horizons in soils under Forest Campinarana provided potential errors in the determination of soil moisture, requiring calibration data for the precise use of this device. The investigation of the soil through the GPR showed interesting results, which allowed continuous visual- ization of the main soil horizons along transects in the phytophysiognomies of Campinaranas. Keywords Campinarana . GPR . Moisture sensor calibration . Sandy soils . Soil moisture monitoring 1 Introduction The vegetation of the Campinaranas, also known as Campinas or Amazon Caatinga , occurs in humid areas and in hydromor- phic sandy soils of the Amazon region, called the white-sand soils (Anderson 1981). This vegetation is characterized by a striking contrast with the surrounding rainforest landscape on clayey soils. Vegetation types in Campinaranas are strongly influenced by annual cycles and by consequent changes in water table levels, so that physiognomic gradients occurs asso- ciated with different soil hydrological conditions (Mendonça et al. 2013). Similarly to the floodplains and flooded forests of the Amazon region, the flora distribution in Campinaranas is also associated with the dynamics of water in periods with and without flooding (Prance 1996; Ferreira 1997). However, the literature on Amazon Campinaranas is sparse, with much discussion and controversy about the origin of this vegetation (Ducke and Black 1954; Anderson et al. 1975; Anderson 1978; Prance and Schubart 1978; Anderson Responsible editor: Ying Ouyang B. A. F. de Mendonça (*) : E. I. F. Filho : C. E. G. R. Schaefer : A. F. de Carvalho Soil Department, Federal University of Viçosa, 36570-900 Viçosa, MG, Brazil e-mail: brunoafmendonca@gmail.com J.F. do Vale Jr. Soil and Agricultural Engineering Department, Federal University of Roraima, 69300-000 Boa Vista, Roraima, Brazil G. R. Corrêa Biodiversity and Forest Institute, Federal University of West of Pará, 68035-110 Santarém, Pará, Brazil J Soils Sediments (2014) 14:525–537 DOI 10.1007/s11368-013-0811-2