Deforestation and land use change mediate soil carbon changes in the eastern Brazilian Amazon

• Published in: Regional environmental change Vol. 21; no. 3
• Main Authors: Damian, Júnior Melo, Durigan, Mariana Regina, Cherubin, Maurício Roberto, Maia, Stoécio Malta Ferreira, Ogle, Stephen M., de Camargo, Plínio Barbosa, Ferreira, Joice Nunes, de Oliveira Júnior, Raimundo Cosme, Cerri, Carlos Eduardo Pellegrino
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.09.2021; Springer; Springer Nature B.V
• Subjects: Agricultural land; Carbon; Carbon content; Climate Change; Climate Change/Climate Change Impacts; Deforestation; Earth and Environmental Science; Environment; Forest biomass; Forests; Geography; Global temperature changes; Land cover; Land use; Nature Conservation; Oceanography; Original Article; Pasture; Regional management practices with positive effects on soil carbon to meet the goals of the 4p1000 initiative; Regional/Spatial Science; Soil types; Soils; Uncertainty; Brazil; Amazon Basin; Monte Carlo method; Climate change; Tropical forest; Soil organic carbon; Carbon sequestration; Land use intensity
• ISSN: 1436-3798; 1436-378X
• DOI: 10.1007/s10113-021-01796-w

Deforestation and land use change (LUC) to expand the agricultural frontier in the Brazilian Amazon deplete soil carbon (C) stocks, and negatively impact climate regulation. The variety of soil types, land-transition options, and management practices present in the Amazon region require detailed inventories to reduce the uncertainties associated with estimates of soil C change. Therefore, we conducted a study covering ca. 1 million hectares to estimate the soil C stock changes due to LUC in Paragominas and Santarém, Pará state, eastern Brazilian Amazon, for the period of 1990–2010. Soil C stocks for 1990 were modeled based on land cover at the time. In 2010, we carried out a field work taking soil samples to measure soil C stock changes in 356 transects across contrasting land uses (logged and burnt forest, young secondary forest, intermediate secondary forest, old secondary forest, pasture, and cropland). The response ratios for the conversion from undisturbed forest to new land uses were calculated considering the differences in soil C stocks, with the undisturbed forest as reference. Between 1990 and 2010, LUC induced a total loss of 1.51 Tg C year -1 (over an area of 7350 km 2 ). For this period, the uncertainty of estimates was ± 23.2%. The land transitions to pasture and cropland were the main drivers of soil C losses. Thus, deforestation contributes to climate change not only through losses of forest biomass but also subsequently soil C losses. These results can inform national and international climate change initiatives associated with LUC in the eastern Brazilian Amazon.