Pedoindicators attributes in the variation of CO2 efflux in Indian black earth and non-anthropic soils

Abstract

In the last decades, the studies involving the mechanisms of the CO2 emissions dynamics have been studied in several ecosystems with varied soil classes. The objective of this study was to evaluate the relationship between physical and chemical attributes of soils and the variation of CO2 efflux in Indian Black Earth (IBE) and non-anthropogenic soils in the Amazon. The study areas are located in the southern region of Amazonas, specifically in the municipalities of Humaitá and Apuí. Respectively in the natural field and forest areas, grids with dimensions of 70 m x 70 m and 10 m regular spacing between sample points, in the depth of 0.0–0.20 m, totaling 64 samples were delimited. In the IBE area, a 42 x 88 m grid was established, marking points at a 6 x 8 m spacing, totalizing 88 sampling points in the depth of 0.0–0.2 m. The soil physical analyzes performed were bulk density, soil penetration resistance, macroporosity, microporosity, total porosity and texture, and the soil chemical analyzes were composed by organic carbon, organic matter and carbon stocks. The soil CO2 emission (FCO2) was recorded with a portable automated LI-COR soil flow system (LI-8100). The soil temperature (Tsolo) was monitored concomitantly with the soil CO2 emission evaluations using a temperature sensor that is an integral part of the LI-8100 system. Soil moisture was recorded using a Time Domain Reflectometry (TDR) apparatus - Campbel® Hydrosense ™ Campbell Scientific. The data were submitted to descriptive statistical analyzes and multiple linear regression with the pedotransfer functions model criterion. The study demonstrates the variation of physical and chemical attributes of the soil and its influence on CO2 efflux variation, since the different environments studied presented differentiated scales and attributes for each situation, due to the correlations presented.

Keywords

• physical
• chemical
• amazonas