Soil Organic Matter Fractions in Preserved and Disturbed Wetlands of the Cerrado Biome

Abstract

Veredas are humid tropical ecosystems, generally associated to hydromorphic soils and a shallow water table. The soils of these ecosystems are affected by the use of the areas around these veredas. The objective of this study was to determine soil organic matter (SOM) fractions in veredas adjacent to preserved (native savanna) and disturbed environments (agricultural areas and pastures) in the Cerrado biome. Soil samples were collected from the 0-10 and 10-20 cm layers along reference lines drawn along the relief following the upper, middle and lower positions of one of the slopes, in the direction of the draining line of the vereda. The soil analysis determined: total soil OC, total nitrogen and C:N ratio; C and N contents and C:N ratio in particulate and mineral-associated fractions (of SOM); fulvic acids, humic acids and humin fractions and ratio between humic and fulvic acids. The agricultural use around the veredas induced changes in the SOM fractions, more pronounced in the lower part of the slope. In the soil surface of this part, the OC levels in the humic substances and the particulate fraction of SOM, as well as total soil OC were reduced in the vereda next to crop fields. Keywords

Soil organic matter pools under management systems in Quilombola Territory in Brazilian Cerrado

“…The highest values of Hum found in CN1 are due to the lower disturbance level of the area, which promotes greater polymerization of humic compounds. This differentiation of the values of Hum with the adopted type of management was also observed in the study of Sousa et al (2015), in which the conventional soil tillage for vegetable production reduced Hum contents in comparison to the no-tillage.…”

Dinâmica Do Carbono Orgânico De Solos Sob Pastagens Em Campos De Murundus

“…A MOS desempenha diversas funções no ambiente, estando ligada a processos fundamentais como a ciclagem e retenção de nutrientes, agregação do solo e dinâmica da água, além de ser a fonte básica de energia para a atividade biológica (MACHADO, 2001;CARVALHO et al, 2010) e sua perda pode interferir drasticamente em vários processos, dificultando o desempenho das funções do solo, provocando desequilíbrios no sistema e, consequentemente, desencadeando o processo de degradação. Nesse contexto, o uso do solo para atividades agropecuárias frequentemente altera os teores de carbono do solo (MAIA et al, 2010;CARVALHO et al, 2010;SOUSA et al, 2015). Consequentemente, os principais constituintes da MOS, tais como o CO e N, são afetados (MAIA et al, 2010;SOUZA et al, 2009), podendo contribuir para as mudanças climáticas.…”

“…Assim, doravante esse trabalho usará o termo carbono do solo (CS) para designar os vários estudos envolvendo a MOS. Dessa forma, alguns trabalhos recentemente têm investigado qual a magnitude da alteração dos estoques de CS quando áreas nativas são convertidas para utilização agropecuária (RANGEL; SILVA, 2007;PORTUGAL et al, 2008;CARVALHO et al, 2010;SCHIAVO et al (2011SOUSA et al, 2015;OLIVEIRA et al, 2017), pois o estoque de carbono pode ser indicativo de qualidade do solo. Além disso, o estudo das frações lábeis do CS pode fornecer informações sobre as alterações ocorridas em períodos curtos de utilização dessas áreas.…”

“…Devido às condições hidromórficas dessas áreas, em grande parte do ano, vários estudos mostram que a dinâmica da MOS pode ser completamente alterada, conforme mostram o trabalho de Sousa et al (2015).…”

Soil Carbon Stocks under Amazonian Forest: Distribution in the Soil Fractions and Vulnerability to Emission

“…However, despite the importance, there are few studies that can quantify the carbon contained in the soil fractions under primary forest. Recently in Brazil, several authors has investigated the carbon stocks in soil organic matter (SOM) under áreas of substitution of native Cerrado vegetation by agroecosystems (Ferreira et al, 2016), about disturbed wetlands of the Cerrado biome (Souza et al, 2015), about carbon stocks under areas primary forestry (Marques et al, 2016), to evaluate changes in SOM after organic compost application (Silva et al, 2016) and changes in soil total organic C content and labile organic matter fractions in response to cover crop cultivation in an orange orchard (Oliveira et al, 2016a) and changes in soil organic carbon fractions to sugarcane planting due expansion of sugarcane into pastures (Olaya et al, 2016;Oliveira et al, 2016b;Signor et al, 2014).…”