A review on soil carbon accumulation due to the management change of major Brazilian agricultural activities

Abstract

Agricultural areas deal with enormous CO 2 intake fluxes offering an opportunity for greenhouse effect mitigation. In this work we studied the potential of soil carbon sequestration due to the management conversion in major agricultural activities in Brazil. Data from several studies indicate that in soybean/maize, and related rotation systems, a significant soil carbon sequestration was observed over the year of conversion from conventional to no-till practices, with a mean rate of 0.41 Mg C ha -1 year -1. The same effect was observed in sugarcane fields, but with a much higher accumulation of carbon in soil stocks, when sugarcane fields are converted from burned to mechanised based harvest, where large amounts of sugarcane residues remain on the soil surface (1.8 Mg C ha -1 year -1 ). The higher sequestration potential of sugarcane crops, when compared to the others, has a direct relation to the primary production of this crop. Nevertheless, much of this mitigation potential of soil carbon accumulation in sugarcane fields is lost once areas are reformed, or intensive tillage is applied. Pasture lands have shown soil carbon depletion once natural areas are converted to livestock use, while integration of those areas with agriculture use has shown an improvement in soil carbon stocks. Those works have shown that the main crop systems of Brazil have a huge mitigation potential, especially in soil carbon form, being an opportunity for future mitigation strategies.Keywords: greenhouse gas, mitigation strategies, soil carbon stock, carbon dioxide, agriculture. Uma revisão sobre o acúmulo de carbono no solo devido a mudança de manejo nas principais atividades agrícolas do Brasil ResumoÁreas agrícolas trocam enormes fluxos de CO 2 , oferecendo uma oportunidade para mitigar o efeito estufa. Neste trabalho, estudou-se o potencial de sequestro de carbono em razão da conversão no manejo das principais atividades agrícolas do Brasil. Dados de vários estudos têm indicado que no sistema soja/milho e nas respectivas rotações, ocorre um sequestro de carbono no solo significativo ao longo dos anos de conversão do plantio convencional para o plantio direto, com uma média de 0,41 Mg C ha -1 ano -1. O mesmo efeito tem sido observado nos canaviais, porém há maiores acúmulos de carbono no solo quando as áreas de cana-de-açúcar são convertidas da colheita baseada na queima para a mecanizada, em que grandes quantidades de palha são deixadas na superfície do solo (1,8 Mg C ha -1 ano -1). Esse maior potencial de acúmulo de carbono no solo nos canaviais, comparado com outras culturas, está diretamente relacionado com a maior produção primária dessa cultura. Apesar disso, muito desse potencial de sequestro é perdido, uma vez que os canaviais são reformados, sob preparo intensivo do solo. As áreas de pasto mostram uma depleção nos estoques de carbono, quando convertidas de áreas naturais; porém, a integração dessas áreas com agricultura pode promover o aumento nos estoques de carbono do solo. Os trabalhos têm mostrado que as princi...

Soil Organic Matter Quality in Jatropha spp. Plantations in Different Edaphoclimatic Conditions

“…(Table 2). Annual cropping, with intense soil turnover, causes a reduction in the C stock accumulated in the soil profile, as observed by Corazza et al (1999) andLa Scala Junior et al (2012).…”

“…can be used to preserve soil as well as accumulate C in the soil (Srivastava et al, 2014). In this latter respect, several studies have shown that growing crops for production of renewable energy also has potential for accumulating C in the soil by incorporation of substantial amounts of plant residues (La Scala Junior et al, 2012;Srivastava et al, 2014;Souza et al, 2015).…”

Soil CO2–C Emissions and Correlations with Soil Properties in Degraded and Managed Pastures in Southern Brazil

“…Despite the large areas of degraded pasture in Brazil, scarce information exists about the variation and correlations of soil properties including nutrients and soil carbon in those pasture management systems (Cerri et al, 2004;La Scala Jr. et al, 2012). Such information would contribute to better characterization of pasture areas, providing additional information to avoid further pasture degradation, as an important strategy to face global climate change and increase food production.…”

“…Fearnside & Barbosa (1998) showed that pasture soils could be a net sink or a net source of CO 2 -C depending on their management. Nevertheless, different aspects are still being discussed from studies concerning the potential for agricultural soils to be a sink rather than an emission source of greenhouse gases (Smith, 2004;Brevik, 2012;La Scala Jr. et al, 2012;Alexander et al, 2015), and additional knowledge should be obtained to better comprehend the potential of soils to avoid additional CO 2 -C losses and, thus, to become a C sink. Additionally, de Moraes Sá et al (2015) presenting results from soil CO 2 -C depletion and strategies for its restoration showed that relatively rapid changes in the soil organic carbon (SOC) stock with no till systems (high and diversified annual C input) indicate that there is a large potential to reverse the process of soil degradation through conversion to the no till systems.…”

Distribuição espacial do efluxo de CO2 em área de terra preta arqueológica sob cultivo de cacau e café no município de Apuí, AM, Brasil

“…As TPAs, por sua vez, podem apresentar, em média, até 6 vezes mais carbono orgânico estável que os solos adjacentes sem horizonte A antrópico (Glaser, 2001), figurando como grande reservatório de carbono orgânico. Entretanto, com a modificação da cobertura da vegetação nativa por meio das ações antrópicas atuais, é possível que haja perdas massivas de C do solo (La Scala Júnior et al, 2012).…”