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Changes in soil profile carbon and nitrogen dynamics <BR>by agricultural management practices (Communication session)

EUROSOIL2020CONT-2859

CARBON STOCK AS A PREDICTOR OF SOIL HEALTH IN BANANA CROPS LOCATED IN THE ATLANTIC FOREST REGION.

Reginaldo B. Silva¹, Jéssica S. Rosa¹, Ana P. C. Paker², Camila B. Bento^{* 2}, Francisca A. M. Silva¹

¹Departament of Agronomy, São Paulo State University (UNESP), Registro, ²EMBRAP Environment, Brazilian Agricultural Research Corporation (EMBRAPA), Jaguariuna, Brazil

Content: The soils of Brazilian biomes are particularly sensitive since it has specific geological and weather conditions, as well as countless endemic macro and microorganisms. Currently, the Ribeira Valley region, in São Paulo state, is one of the last and largest areas with remnant or native vegetation of Atlantic Forest. Nevertheless, the region has been living for several years with anthropogenic and agricultural activities resulting in land use change to banana production (Musa spp.). The banana orchards demand soil management including tillage, liming, and fertilizers application. In the case of initial conversion to banana orchards, the area also needs to be cleaned through superficial vegetation removal. Considering this cropping system, we conducted a study in Ribeira Valley aiming to compare the soil carbon stocks in Atlantic Forest, as a referential area, with the ones in a banana orchard converted from a forest remnant more than 30 years ago. Soil samples in banana plantation (BP) and forest remnant (FR) were collected in 2018 from 0 to 100 cm layer, and then samples were analyzed by dry combustion to CS calculation using the conventional methodology and two soil mass adjustment methodologies. As expected, the results showed that carbon stocks decreased from the top to the deeper layers in both land-uses. Total carbon stocks was 260.82 Mg C ha^-1 in FR and 207.98 Mg C ha^-1 in BP to the conventional methodology calculation, which means that FR accumulated 52.84 Mg ha^-1 more C than BP from 0 to 100 cm layer. However, taking into account the adjustment methodologies, the carbon stocks in FR accumulated 61.80 and 73.63 Mg ha^-1 more C than BP. Moreover, BP presented carbon stocks 4.3% and 10% lower using adjustment methodologies when compared by the relative differences among methodologies. Consequently, once there was a clear difference in carbon stocks depending on the chosen methodology, a preliminary study listing the characteristics of the soil profile, tillage history, and plant morphology should be done to decide for the better methodology to soil mass correction. Considering our results it was evident the effect of the banana orchard to reduce carbon stocks when converted from forest vegetation even when it comes to a remnant one. These findings lead us to understand the soil management of banana plantation, following conventional agriculture systems, as a potential carbon stocks reducer and a factor resulting in loss of soil health in the region. Additionally, our data can be used by environmentalists and government policymakers to promote environmental sustainability.

Disclosure of Interest: None Declared

Keywords: Carbon, Land Use Change, Remnant Forest, Ribeira Valley