Soil carbon and nitrogen under different land-use and landscape loca-tions in central Brazil

Fábio Luís De Souza Santos,Antônio Felipe Couto Júnior,Gabriela Bielefeld Nardoto,Adriana Reatto,Arminda Moreira De Carvalho,Éder De Souza Martins

doi:10.20873/jbb.uft.cemaf.v9n2.santos

Fábio Luís De Souza Santos, Antônio Felipe Couto Júnior + Show 4 more

Open Access

https://doi.org/10.20873/jbb.uft.cemaf.v9n2.santos

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Abstract

In Central Brazil, plateaus, the most common geomorphologic form, have been undergoing intense conversion from native vegetation to pasture and agriculture in recent decades. We used carbon stable isotope ratios (δ13C) and nitrogen stable isotope ratios (δ15N) to assess possible changes in soil organic matter dynamics under such land use modifications. This study aimed to evaluate the differences in soil δ13C and δ15N and C and N stocks between native vegetation and agricultural or pasture areas in different locations of a plateau in the savannas of Central Brazil. We sampled soil up to 100 cm depth in pasture areas in the summit of the plateau and no-tillage and conventional tillage on the border of a plateau, as well as soils under native vegetation in both landscape locations. Both soil δ13C and δ15N, and C and N stocks showed no differences between land uses. The different relationships between δ15N and C/N ratio at different locations indicated distinct behavior of the soil organic matter between the summit and border of the plateau. Therefore, in addition to land-use, landscape location contributes to both δ13C and δ15N, and C and N stocks in the soil of the plateau.

Highlights

Land use changes (LUC) imply modifications in both carbon (C) and nitrogen (N) cycling, and in the functioning of ecosystems (Steffen et al, 2015)
The differences due to LUC can occur through the increase or reduction of C and N stocks (Guareschi et al, 2014), which vary with the intensity of the changes and the management provided to each area (Cecagno et al, 2018; Marinho Junior et al, 2020)
The study area comprises the experimental basin of the Sarandi stream, whose source is located in Planaltina, Distrito Federal, Brazil, with altitudes between 930 and 1,270 m (Figure 1)

Summary

Introduction

Land use changes (LUC) imply modifications in both carbon (C) and nitrogen (N) cycling, and in the functioning of ecosystems (Steffen et al, 2015). The differences due to LUC can occur through the increase or reduction of C and N stocks (Guareschi et al, 2014), which vary with the intensity of the changes and the management provided to each area (Cecagno et al, 2018; Marinho Junior et al, 2020). Studies have observed a relationship between landscape location and the δ13C (Doetterl et al, 2016) and the δ15N in soil (Weintraub et al, 2015), given that LUC can influence behavior of the organic matter (Mudge et al, 2014). Different landscape locations are determinant of the ecosystem structure and functioning (Arruda et al, 2015), affecting physical, chemical and microbiological attributes of soils (GamaRodrigues et al, 2018)

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Conclusion