Estoques de carbono e nitrogênio no solo devido a mudança do uso da terra em áreas de cultivo de café em minas gerais

The type of previous land use to the coffee cultivation and the adopted management practices of coffee pruning may affect the dynamics of soil carbon (C) and nitrogen (N). Thus, the aim of this study was to quantify soil C and N stocks in the three main coffee production regions of Minas Gerais State, evaluating different management systems and coffee cultivation time compared to cultivated pastures. For the calculation of C and N stocks, soil samples were collected to determine the content of C and N, in addition to soil density at different depths. Evaluated situations included management of coffee areas with and without pruning, and the type of previous land use to the coffee crop currently in the areas (i.e. pasture or coffee). The results indicated that coffee cultivation under grazing areas along with the adoption of good agricultural practices such as proper management of pruning and good weed control led to the maintenance of soil C and N stocks over time. Through this fact, it is possible to state that coffee cultivation positively affects soil health.O tipo de uso da terra anterior ao plantio de café e o manejo de podas adotado no cafezal podem condicionar a dinâmica do carbono (C) e do nitrogênio (N) no solo. Desta forma, o objetivo neste trabalho foi quantificar os estoques de C e N do solo nas três principais regiões produtoras de café de Minas Gerais, avaliando diferentes sistemas de manejo e cultivo do café em comparação com pastos cultivados. Para o cálculo dos estoques foram coletadas amostras de solo para determinação dos teores de C e N, além da densidade em diferentes profundidades. As avaliações incluem manejo das áreas com e sem podas, e o tipo de uso da terra anterior ao cultivo do café. Os resultados indicam que o cultivo do café sobre áreas de pastagem, com adoção de boas práticas agrícolas como um manejo adequado de podas e bom controle do mato, propicia a manutenção dos estoques de carbono e nitrogênio do solo. Através deste fato pode-se mencionar que a cafeicultura reflete positivamente na saúde do solo

Assessing the greenhouse gas emissions of Brazilian soybean biodiesel production.

Soybean biodiesel (B100) has been playing an important role in Brazilian energy matrix towards the national bio-based economy. Greenhouse gas (GHG) emissions is the most widely used indicator for assessing the environmental sustainability of biodiesels and received particular attention among decision makers in business and politics, as well as consumers. Former studies have been mainly focused on the GHG emissions from the soybean cultivation, excluding other stages of the biodiesel production. Here, we present a holistic view of the total GHG emissions in four life cycle stages for soybean biodiesel. The aim of this study was to assess the GHG emissions of Brazilian soybean biodiesel production system with an integrated life cycle approach of four stages: agriculture, extraction, production and distribution. Allocation of mass and energy was applied and special attention was paid to the integrated and non-integrated industrial production chain. The results indicated that the largest source of GHG emissions, among four life cycle stages, is the agricultural stage (42-51%) for B100 produced in integrated systems and the production stage (46-52%) for B100 produced in non-integrated systems. Integration of industrial units resulted in significant reduction in life cycle GHG emissions. Without the consideration of LUC and assuming biogenic CO2 emissions is carbon neutral in our study, the calculated life cycle GHG emissions for domestic soybean biodiesel varied from 23.1 to 25.8 gCO2eq. MJ-1 B100 and those for soybean biodiesel exported to EU ranged from 26.5 to 29.2 gCO2eq. MJ-1 B100, which represent reductions by 65% up to 72% (depending on the delivery route) of GHG emissions compared with the EU benchmark for diesel fuel. Our findings from a life cycle perspective contributed to identify the major GHG sources in Brazilian soybean biodiesel production system and they can be used to guide mitigation priority for policy and decision-making. Projected scenarios in this study would be taken as references for accounting the environmental sustainability of soybean biodiesel within a domestic and global level

Life cycle of soybean biodiesel produced in Brazil, highlighting GHG emission sources within the four stages: agriculture, extraction, biodiesel production and distribution.

<p>Life cycle of soybean biodiesel produced in Brazil, highlighting GHG emission sources within the four stages: agriculture, extraction, biodiesel production and distribution.</p

Summary of conversion factors used in this study.

<p>Summary of conversion factors used in this study.</p

Relative share of GHG emissions in each stage (agriculture, extraction, biodiesel production and distribution) for B100 produced from integrated and non-integrated plant considering the MT-PA and MT-EU scenarios.

<p>Relative share of GHG emissions in each stage (agriculture, extraction, biodiesel production and distribution) for B100 produced from integrated and non-integrated plant considering the MT-PA and MT-EU scenarios.</p

Life cycle GHG emission of B100 based on four different transportation routes.

<p>Life cycle GHG emission of B100 based on four different transportation routes.</p

Life cycle GHG emission of biodiesel production, considering a domestic B100 scenario (MT-PA) and an exported B100 scenario (MT-EU).

<p>Life cycle GHG emission of biodiesel production, considering a domestic B100 scenario (MT-PA) and an exported B100 scenario (MT-EU).</p

Schematic representation of the four pathways for distribution of final B100.

<p>Schematic representation of the four pathways for distribution of final B100.</p

Main inputs and yield per hectare of soybean in Mato Grosso state, Brazil (growing season of 2007/08, 2008/09 and 2009/10).

<p>Main inputs and yield per hectare of soybean in Mato Grosso state, Brazil (growing season of 2007/08, 2008/09 and 2009/10).</p

Previous LCA emission studies of Brazilian soybean (-derived) products.

<p>Previous LCA emission studies of Brazilian soybean (-derived) products.</p