Application of δ13C and δ15N in studies on organic matter dynamics in superficial soils in Brazil: a synthesis and perspectives
DOI:
https://doi.org/10.26848/rbgf.v18.3.p1940-1960Keywords:
Stables Isotopes, Temperature, Precipitation, C/N ratioAbstract
Stable isotopes of carbon (δ13C) and nitrogen (δ15N) in soil provide information on the dynamics of organic matter in ecosystems. Climate, relief and vegetation cover can influence such dynamics at different scales, conditioning the values of δ13C and δ15N. The objective of this study was to identify the environmental factors that most influence variations in δ13C and δ15N of surface soils in Brazil and identify existing trends based on literature data. Values of δ13C and δ15N were compiled up to 20cm deep in different biomes in Brazil. A distribution analysis of the most cited terms was carried out to evaluate the context of the use of δ13C and δ15N soil in Brazil. A linear regression model was generated between δ13C and δ15N and the variables temperature, precipitation, soil pH, C/N ratio and carbon concentration. Studies with δ13C are related to changes in land use, carbon stock and paleoecology. Studies with δ15N serve to determine trophic chains, functional attributes and ecosystem functioning. Soil δ13C showed a negative relationship and δ15N a positive relationship with temperature. The linear models of δ13C (R² = 0.53) and δ15N (R² = 0.48) were significant. The soil C/N ratio has a positive relationship with δ13C and a negative relationship with δ15N. Carbon concentration and precipitation negatively influenced the values of δ13C and δ15N, respectively. In addition to climate, other environmental factors contribute to soil δ13C and δ15N values in Brazil, mainly the C/N ratio.
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