Carbon and nitrogen stocks in soils under different forms of use in the Cerrado

Abstract

The soil is an important component in the biogeochemical cycling of carbon (C) and nitrogen (N). The objective of this study was to evaluate the changes caused by different types of land use on the C and N stocks in areas of Cerrado at different depths: area under conventional tillage, no-tillage, grazing, eucalyptus and area under native vegetation of Cerrado in the municipality of Luis Eduardo Magalhães, BA, Brazil. The highest C content was found for no-tillage area in the surface layer up to 10 cm; however, there was a decrease in its content along the depths. Areas under no-tillage had lower values of C in the surface layer (0-5 cm) and below 20 cm. Among these, C stocks were significantly lower compared to the use of grass and eucalyptus at the depth of up to 40 cm. Considering the depth of 0-60 cm, the highest C stock was found in areas under native vegetation, 62.81 Mg ha-1, followed by the area under cultivation with eucalyptus, 60.70 Mg ha-1. The lowest C stocks were found in areas under conventional use, 44.87 Mg ha-1. Conventional planting reduced N stocks by up to 61 and 56% when compared to areas under native Cerrado vegetation and eucalyptus plantations, respectively, both at a depth of up to 10 cm. Therefore, land use practices such as eucalyptus cultivation and no-tillage contribute to C and N storage over time.

Carbon in the Labil Fractions of Soil Organic Matter in Savannah Areas

“…Regarding the carbon management index, it is observed that in the SAFs and EUC there was an increase in depths of up to 30 cm, demonstrating that agroforestry systems and 7-year-old eucalyptus plantations are capable of increasing soil organic matter. similar results were found by Costa et. al., (2020b) in eucalyptus plantations.…”

Distribution of available nitrogen forms in soil under Quilombola management systems in Brazilian Cerrado phytophysiognomies

“…Natural areas commonly accumulate organic matter in the topsoil, which could increase of the Av-N content. In contrast, areas that have undergone LUC (e.g., Cerradão in pastures or monocultures) tend to decrease the N content in the soil profile (Kizilkaya and Dengiz, 2010;Groppo et al, 2015;Borges et al, 2019;López-Poma et al, 2020;Costa et al, 2020). Maize cultivation under the LC presented the lowest available N content compared to other systems.…”

Fractions of Organic Matter and Soil Carbon Balance in Different Phases of an Agroforestry System in the Cerrado: A Ten-Year Field Assessment

“…Among GHGs, the increase in CO 2 emissions caused by changes in land use, including deforestation and conventional tillage systems, requires urgent changes in the way agricultural land is used [1]. The current agricultural model, characterized by intense land use and low diversity of plant species, results in physical, chemical and biological degradation of the system, consequently lowering carbon (C) stocks and reducing the contribution of agriculture to mitigating GHG emissions [2,3].…”

“…Hence, the importance of using agroforestry systems with long-cycle tree components. Several studies have demonstrated an increase in C stock in integrated production systems when compared with conventional agriculture [3,7,10,11,15]. Freitas et al [16] evaluated C stocks in well-managed pastures and agroforestry systems in the Brazilian Cerrado and reported that these systems promoted faster recovery of soil C stocks at all depths, reaching values similar to those in the Cerrado under natural vegetation, in addition to improving other soil properties.…”