Physical fractions of organic matter and mineralizable soil carbon in forest fragments of the Atlantic Forest

Jefferson Matheus Barros Ozório,Jolimar Antonio Schiavo,Naelmo De Souza Oliveira,Eloi Panachuki,Roniedison Da Silva Menezes,Camila Beatriz Da Silva Souza,Jean Sérgio Rosset,Paulo Guilherme Da Silva Farias

doi:10.4136/ambi-agua.2601

Jefferson Matheus Barros Ozório, Jolimar Antonio Schiavo + Show 6 more

Open Access

https://doi.org/10.4136/ambi-agua.2601

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Abstract

This study determined the physical granulometric fractionation evaluated the mineralizable carbon within and around forest fragments of the Atlantic Forest biome located in the state of Paraná. Soil samples were collected at three three internal points of the fragments: the edge (E), the half radius (HR) and the center (CF); and one point in no-tillage system (NTS) areas around the fragments, in four replicates. The contents of total organic carbon (TOC), particulate fraction carbon (C-POM) and mineral fraction (C-MOM) were determined, and the %POM and %MOM and the stocks of POM (StockPOM) and MOM (StockMOM) were calculated, in addition to the indices: carbon stock index (CSI), lability (L), lability index (LI) and carbon management index (CMI), also evaluating CO2 emission, daily and accumulated. The highest TOC levels were observed in the CF point. The highest C-POM contents were observed in the E and CF points of fragment 1, in the CF point of fragment 2, and the highest C-MOM contents were expressed in the CF points of both fragments. CMI showed a distinct pattern among the fragments. The NTS areas showed lower C-CO2 emissions, with 39.8% and 28.3% less total emission compared to CF. The results of physical granulometric fractionation show the CF point favors the quality of SOM and the mineralizable carbon analysis indicated that the conversion of native areas into NTS compromises soil microbial activity.

Highlights

The effect of anthropization on the Brazilian Atlantic Forest biome has generated several impacts on the landscape in general, among them, the increase in forest fragmentation stands out (Warburton, 1997)
The forest fragments of the Atlantic Forest biome presented the highest levels of total organic carbon (TOC) in the center of the fragment (CF) points, differing from the other points within and around the fragments, reaching 63.2 g kg-1 and 60.9 g kg-1 in Fragments 1 and 2, respectively, in the 0-0.05 m layer in the CF points (Figure 2)
The higher levels of TOC in the CF point compared to E and half radius (HR) is mainly due to the greater isolation of this point in relation to the external factors, indicating that the points near the edge suffer greater influence of fragmentation, mainly due to the higher incidence of light and microclimatic changes in these areas (Laurance et al, 1998)

Summary

Introduction

The effect of anthropization on the Brazilian Atlantic Forest biome has generated several impacts on the landscape in general, among them, the increase in forest fragmentation stands out (Warburton, 1997). Forest fragments were defined by Viana and Pinheiro (1998) as areas of natural vegetation interrupted by natural barriers (mountains, rivers, lakes, among others), or anthropic barriers (roads, agricultural activities, cities), which interfere with the flow of fauna, pollen and seed dispersal. With the forest fragmentation of Brazilian biomes, the species are exposed to physical and biotic changes, causing the so-called “edge effect” in the fragments. This effect occurs near the edge of the fragment, where there is greater sensitivity to external agents, making more noticeable the various forms of changes, such as vegetation variation, with changes in edaphic attributes over time, due to several regional factors (Malchow et al, 2017)

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