Carbon Dynamics in Humic Fractions of Soil Organic Matter Under Different Vegetation Cover in Southern Tocantins

Josué Luiz Marinho Junior,Renisson Neponuceno Araújo Filho,Raimundo Rodrigues Gomes Filho,Alceu Pedrotti,Moacyr Cunha Filho,Milton Marques Fernandes,Francisco Sandro Rodrigues Holanda,Saulo Boldrini Gonçalves,Victor Casimiro Piscoya

doi:10.1590/2179-8087-floram-2020-0024

Abstract

Abstract Soil organic matter has great importance in chemical, physical and biological processes in soil-plant system. This study aimed to evaluate changes in carbon humic fractions of soil organic matter under different vegetation coverings in Cerrado in Tocantins, Brazil. The work was developed in Eucalyptus sp., Pasture, Agriculture and Cerrado sensu stricto areas. Soil samples were collected in dry period, October, 2018, in trenches 70 x 70 cm at depths 0-10, 10-20, 20-30, 30-40 and 40-50 cm, with six replications. The vegetation cover in Eucalyptus sp. area showed higher levels of total carbon in soil humic fraction. Respectively fulvic acid, humic acid and humin in Eucalyptus sp. area had stocks of 22.09; 2.71 and 20.01% higher than native forest, 32.04; 2.57 and 35.59% higher than pasture and 10.59; 19.19 and 7.61% higher than the agriculture area. Among the different areas evaluated, the soil of Eucalyptus sp. has great potential to increase carbon storage in soil humic fractions.

Highlights

AND OBJECTIVESSoil organic matter (SOM) is extremely important as soil quality key indicator, as its accumulation influences physical and chemical properties of soil (Dhaliwal et al, 2019)
This study aimed to evaluate changes in carbon humic fractions of soil organic matter under different vegetation coverings in Cerrado in Tocantins, Brazil
The work was developed in Eucalyptus sp., Pasture, Agriculture and Cerrado sensu stricto areas

Summary

Introduction

AND OBJECTIVESSoil organic matter (SOM) is extremely important as soil quality key indicator, as its accumulation influences physical and chemical properties of soil (Dhaliwal et al, 2019). Humus is result of biological animals decomposition, microorganisms and mainly plants, consisting of compounds in various stages of decomposition, closely linked to soil clay minerals (Stevenson, 1994). The SOM has two fundamental groups, one consisting in decomposition products of organic residues and microorganisms metabolism that represents about 10 to 15% of the TOC reserve in mineral soils (Dhaliwal et al, 2019) and humic substances, with emphasis on humic acid, fulvic acid and humin, representing 85 to 90% of TOC reserve (Pegoraro et al, 2018). The humic fraction is composed of organic residues having a high decomposition degree, Creative Commons License.

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Results