Impacts of land-use change on carbon stocks and dynamics in central-southern South American biomes: Cerrado, Atlantic Forest and Southern Grasslands.

Abstract

Land-use changes (LUC) are one of most significant global change processes of the current era, with noticeable consequences on habitat loss, due mainly to agricultural expansion and urbanization. The carbon cycle dynamics can be affected significantly by LUC, with impacts on carbon sequestration and emission rates. Considering the direct effect of carbon gases enrichment of the atmosphere on climate change, it is of utmost importance to improve the knowledge base on the impacts of agricultural-based LUC on carbon sinks, such as soils. This chapter reviews the available data on the effects of LUC on soil carbon stocks in three major biomes of the southern portion of the South American continent (the Cerrado, the Southern Grasslands and the Atlantic Forest). The area of soybean crops has expanded almost four times in the La Plata Basin Grasslands of Argentina over the past decade, and near ten times in the Brazilian Cerrado since the mid-1980s. The area under sugarcane crops in Brazil has almost doubled since the mid-1990s, occupying approximately 8.5 million ha (Mha) in 2009. In 2011, forestry plantations occupied 28% more land in Brazil than in 2005, with a total area of 6.5 Mha (75% with Eucalyptus and 25% with Pinus). In general, all conversions of natural vegetation to agricultural land-use systems in the different biomes have resulted in significant losses of soil carbon stocks. The conversion of pastures and grasslands to annual croplands in the Rolling Pampas grasslands has decreased C stocks by 50% over the last century. This represents a much faster loss rate than the loss triggered by the introduction of domestic herbivores over the course of the previous nearly four centuries (22%). These results imply that soil degradation caused by annual crops is very rapid and results in a strong decrease in carbon stocks. However, adopting soil and water conservation management strategies and increasing the complexity of the cropping systems - through adoption of no-tillage (NT) agriculture, well-managed pasture systems, integrated crop-livestock-forestry systems, multiple cropping and crop rotation with legume cover species, for example, can improve soil carbon sequestration rates by up to nearly 2.0 Mg C ha-1 year-1. The elimination of preharvest burning practices in sugarcane crops alone can result in gains of up to 0.93 t C year-1 ha-1. Improving soil and crop management to boost carbon sequestration in agricultural systems, while at the same time increasing resilience by improving soil quality, is a potential climate change mitigation option for farmers in South America.

Resistance of Soil Organic Matter in “Humic A Horizons” of the Mountainous Region in the State of Rio De Janeiro

“…Although the use of agriculture is admittedly deleterious to soil C stocks (Carvalho et al, 2010;Coutinho et al, 2014), in pastures, I could be found distinct results when compared to other authors who reviewed the world literature (Guo & Gifford, 2002), or even had been worked more locally (in the Atlantic Forest biome) (Tarré et al 2001;Cerri et al, 2007), as they detected an increase in C levels and stocks after converting forest to pasture; on the other hand, this change has not occurred for soils with humic A horizon. The evidence of susceptibility to C-CO 2 loss from these soils seemed to be relevant for these soils, but more soils must be sampled and characterized.…”

“…The C stock varied greatly between sites: soil under passion fruit cultivation showed a C stock of 162.64 Mg ha −1 , whereas soil under Eucalyptus plantation had a C stock of 284.69 Mg ha −1 . These values are higher than those reported in previous studies for soils subjected to different uses in low-altitude regions 6/9 Fontana A, Pereira MG, Balieiro FC, Chagas CS, Donagemma GK, Oliveira LS Floresta e Ambiente 2020; 27(1): e20190091 (Vieira et al, 2011;Villela et al, 2012;Coutinho et al, 2014;Martins et al, 2015). The C stock changes in the humic A horizon can be a result of several factors, including inherent characteristics related to the formation of the soil, as well as past and present land use and management practices-from wood harvesting since colonization and coffee and cattle production days to modern times.…”

Carbon Stock Estimates due to Land Cover Changes at Sumber Brantas Sub-Watershed, East Java

“…In the mixed forest, it was estimated that there would be a carbon loss of about 46% of the total C-stock in 2008 (845.46 Mg). All conversions of natural vegetation to agricultural land-use systems in the different biomes have resulted in significant losses of soil carbon stocks (Coutinho et al, 2015). On the contrary, the carbon stored in the agricultural land would be increased by (184.63 Mg on average).…”

Current overview and potential applications of the soil ecosystem services approach in Brazil

“…Soil ecosystem services References Soil compaction Aeration; flow of water and nutrients; plant growth; water regulating; water storage; food supply; erosion control Reichert et al (2007) Erosion processes Primary production; soil formation and renewal; nutrient cycling; platform; refuge; water storage; food, fiber, fuel and wood (biomaterials); mineral raw materials; biodiversity and genetic resources; recycling and remediation activities; water quality and quantity regulation; flood and drought control; erosion control; recreation; aesthetic and heritage functions Minella et al (2010), Lima & Lopes (2011), Guerra et al (2014 Soil contamination Nutrient cycling; platform; refuge; food, fiber, fuel and wood (biomaterials); biodiversity and genetic resources; recycling and remediation activities; regulation of water quality; recreation Dellamatrice & Monteiro (2014) Carbon stock reduction Primary production; soil formation and renewal; nutrient cycling; refuge; food, fiber, fuel and wood (biomaterials); biodiversity and genetic resources; pathogen and disease control; GHG and climate regulation Carvalho et al (2010) Lima et al (2012) Madari et al (2012, Coutinho et al (2014), Perrin et al (2014) Reduction of soil fertility and biodiversity Primary production; soil formation and renewal; nutrient cycling; refuge; food, fiber, fuel and wood (biomaterials); biodiversity and genetic resources; pathogen and disease control; recycling and remediation actions Vezzani & Mielniczuk (2009), Chaer (2010 Vegetation fragmentation in the landscape Primary production; soil formation and renewal; nutrient cycling; refuge; water storage; mineral raw materials; biodiversity and genetic resources; pathogen and disease control; water quality and quantity regulation; flood and drought control; GHG and climate regulation; erosion control; recreation; aesthetic and heritage function Sparovek et al (2010), Ferreira (2014 Pesq. agropec.…”