Soil Organic Carbon Stabilization on Forested and Deforested Red-yellow Soil under Different Temperature Conditions

Abstract

Soil organic carbon (SOC) has an important role as a key indicator for soil health due to its contributions on mitigation and adaptation to climate change. Tropical areas cover with Red-yellow soil (Udults) such as Amazon represents the highest amount of soil carbon sources in the earth. Although it is affected by human impacts due to deforestation, it is important to maintain and increase SOC of tropical Red-yellow soil toward an optimal level for meeting challenges such as mitigating climate change effects. The aim of this study is to analyze the stabilization of soil organic carbon from Red-yellow soil under different temperatures conditions. A detailed comparison was made between forested and deforested conditions of Red-yellow soil. In order to analyze the temperature sensitivity, each treatment was kept under 25ºC and 35ºC, and the soil respiration ratio (SRR) was measured as well as SOC content by spectrophotometry method. Lastly, a treatment of biochar at 5% was added as part of stabilization mechanisms of carbon. The experimental results showed that there were significant differences in SOC content between forested conditions in contrast to deforested conditions, where 7.25 mg C/g was found in forest conditions while deforested conditions was 5.68 mg C/g. Although it was not found significant change in SOC under different temperature, SRR increased at 39% from 8.87 μL CO₂/h/g to 11.90 μL CO₂/h/g with temperature changes from 25ºC to 35ºC. Additionally, biochar application contributes to increase the value of SOC at more than 2.66 mg C/g in all treatments, however, it did not make a significant difference in SRR by temperature changes. Thus, biochar works as carbon sources to maintain and increase SOC content, but stabilization effects on Soil Respiration Ratio (SRR) should be observed in long term.