Effect of biochar addition on CO₂ emission from salt-affected soils under drying-rewetting conditions

Institute of Coastal Environmental Pollution Control, Key Laboratory of Marine Environment and Ecology, Ministry of Education, College of Environmental Science and Engineering, Ocean University of China, Qingdao, Shandong, 266100, China

^* Corresponding author’s e-mail: lpp0227@stu.ouc.edu.cn

Abstract

Under the conditions of global climate change, soils have undergone more complex and frequent cycles of wetting and drying, which has had a significant impact on soil respiration. In order to explore the response of CO₂ emissions from salt-affected soils to biochar (BC) at different pyrolysis temperatures under drying-rewetting conditions, an indoor microcosmic culture experiment was conducted to add maize straw BC at different pyrolysis temperatures (300°C and 600°C) to salt-affected soils to study the influence of BC at different pyrolysis temperatures on the characteristics of CO2 emissions under drying-rewetting conditions. The results indicated that the addition of BC significantly altered the CO₂ emission rate from the soil, subsequently influencing the mineralization of soil organic carbon. BC produced at varying pyrolysis temperatures exhibited distinct effects on the CO₂ emission rates. Specifically, BC pyrolyzed at high temperatures inhibited the mineralization of soil organic carbon, whereas BC produced at low temperatures facilitated this mineralization process. This finding will provide a theoretical and scientific foundation for assessing the carbon sequestration potential of coastal wetlands and for the development of carbon sequestration technologies.