Study shows that carbon and nitrogen losses from the soil persist for nearly a decade after burning, and conversion to agriculture causes even more severe impacts.
Study shows that carbon and nitrogen losses from the soil persist for nearly a decade after burning, and conversion to agriculture causes even more severe impacts.
Frequent forest fires and agricultural expansion are degrading soil health in the southern Brazilian Amazon. This results in lasting damage to carbon (C) and nitrogen (N) stocks, as well as to the overall functionality of ecosystem soils. These findings are presented in a study conducted by researchers from Brazil, the United States, and the United Kingdom at the Tanguro Research Station, located in the transition zone between the Amazon Rainforest and the Cerrado (the Brazilian savannah-like biome), in the Amazonian Arc of Deforestation.
“We’re talking about a fire that isn’t natural. In the Arc of Deforestation, record fires result from a combination of agricultural and livestock expansion, degradation of neighboring native forests, and prolonged droughts caused by climate change – all promoted by human action,” says researcher Mário Lucas Medeiros Naval, the lead author of the study. “Our work shows how these successive fires have a long-term impact on organic matter and other essential soil attributes and how this compares to agriculture in the region,” he comments.
The study, published in the journal Catena, analyzed the effects of forest conversion to agriculture and the frequency of burning on soil organic matter, as well as various physical and chemical indicators of soil health. The researchers compared four scenarios: an intact forest, a forest burned annually, a forest burned every three years, and an area converted to agriculture under a no-till system with crop rotation.
Read more at Fundação de Amparo à Pesquisa Do Estado de São Paulo
Image: Forest degraded by burning in the so-called Arc of Deforestation in the Amazon (Credit: Mário Lucas Medeiros Naval/CENA-USP)
