Low-carbon agriculture in South America to mitigate global climate change and advance food security

Abstract

The worldwide historical carbon (C) losses due to Land Use and Land-Use Change between 1870 and 2014 are estimated at 148 Pg C (1 Pg=1billionton). South America is chosen for this study because its soils contain 10.3% (160 Pg C to 1-m depth) of the soil organic carbon stock of the world soils, it is home to 5.7% (0.419 billion people) of the world population, and accounts for 8.6% of the world food (491milliontons) and 21.0% of meat production (355milliontons of cattle and buffalo). The annual C emissions from fossil fuel combustion and cement production in South America represent only 2.5% (0.25 Pg C) of the total global emissions (9.8 Pg C). However, South America contributes 31.3% (0.34 Pg C) of global annual greenhouse gas emissions (1.1 Pg C) through Land Use and Land Use Change. The potential of South America as a terrestrial C sink for mitigating climate change with adoption of Low-Carbon Agriculture (LCA) strategies based on scenario analysis method is 8.24 Pg C between 2016 and 2050. The annual C offset for 2016 to 2020, 2021 to 2035, and 2036 to 2050 is estimated at 0.08, 0.25, and 0.28 Pg C, respectively, equivalent to offsetting 7.5, 22.2 and 25.2% of the global annual greenhouse gas emissions by Land Use and Land Use Change for each period. Emission offset for LCA activities is estimated at 31.0% by restoration of degraded pasturelands, 25.6% by integrated crop-livestock-forestry-systems, 24.3% by no-till cropping systems, 12.8% by planted commercial forest and forestation, 4.2% by biological N fixation and 2.0% by recycling the industrial organic wastes. The ecosystem carbon payback time for historical C losses from South America through LCA strategies may be 56 to 188years, and the adoption of LCA can also increase food and meat production by 615Mton or 17.6Mtonyear and 56Mton or 1.6Mtonyear, respectively, between 2016 and 2050.

Soil Carbon Dynamics in Soybean Cropland and Forests in Mato Grosso, Brazil

“…The errors associated with C stock calculations in croplands can be large because soil bulk density is difficult to measure accurately (Holmes et al, 2012;Taalab et al, 2013;Veldkamp, 1994), particularly in the upper soil horizons in seasonally dry soils, or in soils that are tilled and impacted by machinery. To observe changes in C stocks following land conversion, the changes must be large enough to detect (De Camargo et al, 1999;Figueira et al, 2016) despite errors associated with bulk density that can be up to 5% of the uncertainty in C stocks (Holmes et al, 2012). According to the projected losses of 27.5 g C m À2 yr À1 through the year 2100 (Eglin et al, 2010), we were looking for a small change in a large pool that may be below our detection limit.…”

“…The conversion of tropical forest to pasture and cropland has fundamentally altered the global C cycle (Baccini et al, 2012;Houghton, 2005;Houghton et al, 2012). Driven by an increasing global demand for beef and grain from a growing human population (Boucher et al, 2012;Brown, 2009), tropical deforestation to date has largely been for conversion to pasture and the C consequences of such conversions have been extensively documented (De Camargo et al, 1999;Fujisaki et al, 2015;Neill et al, 1997;Powers et al, 2011). Although pasture remains a widespread use of tropical land, in the past two decades land has been increasingly converted to highly mechanized agriculture of commodity crops like soybeans (Galford et al, 2011;Laurance et al, 2014;Nepstad et al, 2006;Morton et al, 2016) and little is known about the transition to industrial soy production, which now covers large swaths of the southern Amazon and Cerrado.…”

Production of polyhydroxybutyrate (PHB) and biofilm by Azospirillum brasilense aiming at the development of liquid inoculants with high performance

“…The majority of the Brazilian soils are poor in N, requiring an intense management of chemical N-fertilizers, but the country imports over 70% of the N needed for annual production, resulting in high cost for the farmers (Hungria et al, 2013a). Although N-fertilizers can be easily assimilated by plants, they are also subject to severe losses by leaching and emission into gaseous forms, leading to water pollution, ozone-layer depletion and global warming (Hungria et al, 2013a;Sá et al, 2017). In this context, *Corresponding author.…”

Avaliação do sistema radicular da cana-de-açúcar (<i>Saccharum spp</i>.) sob diferentes quantidades de palha mantidas na superfície do solo

“…Desse montante, 17% serão obtidos de derivados da cana-de-açúcar, fazendo desta a opção mais viável a fim de promover redução das emissões dos gases causadores do efeito estufa. Boa parte das emissões de GEE no país ainda decorre da agropecuária e geração de energia (queima de carvão, gás natural e petróleo) (IPCC, 2014;MCTI, 2016), indicando a crescente importância da adoção de práticas que visem à redução da emissão dos GEE e a manutenção de ambientes sustentáveis para a agricultura (Sá et al, 2017).…”