Técnicas pra caracterização dos estoques de carbono e humificação da matéria orgânica em diferentes sistemas de manejo de solos na região de Mococa (SP).

Devido à crescente preocupação com o meio ambiente, o estudo de solos tem ganho destaque estudos nos últimos anos. O solo é o maior reservatório de Carbono terrestre, assim desempenha papel fundamental no ciclo deste elemento. O estudo do estoque de Carbono no solo é importante pois diferentes tipos de manejo e culturas podem aumentar a concentração deste elemento no solo e assim diminuir o efeito estufa. O objetivo desse estudo foi avaliar as variações dos estoques de carbono no solo e humificação da matéria orgânica do solo (MOS) devido às mudanças de uso do solo em áreas agrícolas e mata nativa. Foram utilizadas as técnicas de Análise Elementar (CHN) e Espectroscopia de Fluorescência Induzida por Laser (LIFS) para análises da concentração de Carbono e do grau de humificação da MOS respectivamente. Foram avaliadas amostras de solo de áreas de mata nativa, café e uma área de café convertida para cana de açúcar sob regime de colheita crua, coletadas na região de Mococa, SP. Os resultados mostram que áreas de mata nativa estocam mais Carbono do que áreas agrícolas, além disso, também foi possível concluir que o estoque de Carbono é mais estável em horizontes mais profundos. Dentre os manejo agrícolas, o Café-CanaCrua foi o que melhor apresentou quantidade de Carbono estável

Greenhouse gas mitigation and offset options for beef cattle production under contrasting pasture management systems in Brazil.

This study estimates the GHG balance (emissions and sinks) related to the beef cattle production in three contrasting production scenarios on Brachiaria pasture in Brazil: 1) Degraded pasture (DP), 2) Managed pasture (MP), and 3) Crop?livestock?forest integration system (CLFIS)

Increase in sugarcane areas and profile change in the agricultural production in Northeast of São Paulo state.

We evaluated the changes in the agricultural production profile of an area at the watersheds of the Mogi-Guaçu and Pardo rivers along a 27-year period using satellite images. The areas used for sugarcane production in 2015 were classified by updating the maps produced by the Canasat project, which were transformed into vectors and added as layers in a Geographic Information System (GIS). We then reclassified the sugarcane areas using on-screen visual interpretation. The polygons of areas which still featured sugarcane in 2015 were maintained. New areas, identified by means of the Google Earth TM's high-resolution images used for the 2015 mapping were added. We mapped the areas of coffee, citrus, eucalyptus and rubber-tree, pastures, native forests, and urban areas using the Google Earth TM image file in a GIS environment and on-screen visual interpretation of high-resolution images, and compared the results to data of 1988. The sugarcane areas, which encompassed a little over 1.0 million hectares (21% of the region's area), increased to about 2.3 million hectares (44% of the region's area). Over this period, the return on investment produced by sugarcane crops was beyond market average in comparison to other agricultural activities, thus leveraging the prices of leaseholds and increasing the competition with other crops for space. The mapping shows a decrease in areas used for husbandry, annual crops ? especially grains/cereals ?, and citrus. Areas used for annual crops such as soybean and maize, decreased from 936 thousand to 352 thousand hectares. There was an intensification in crops, especially with irrigated areas. The area used for citrus decreased from 486.2 thousand hectares (9.4% of the study area) to 301.5 thousand hectares (5.8%). Low profit and phytosanitary problems contributed to this decrease in citrus area. Despite sugarcane's leading role, over the same period there was an increase in areas occupied with coffee, eucalyptus and rubber-tree, native forests and urban areas. The area used for coffee increased over 80%, from 67 thousand hectares (1.3 % of the region's area) to 123 thousand hectares (2.4% of the area). This increase took place mainly at the Mogiana region, near the border of Minas Gerais state. In 2017, the mapping using satellite images showed that about 150 thousand hectares which are currently used for sugarcane crops (7.1% of the area of both watersheds) may be used for a new crop or may be occupied with native forests in order to increase the legal reserve areas within the farms. These are areas with steepness degrees above 12% which cannot be mechanically harvested for sugarcane crop, and which may not be burned for manual harvesting due to the complete prohibition of flaming in the state of São Paulo

Changes in quantity and quality of soil carbon due to the land-use conversion to sugarcane (Saccharum officinarum) plantation in southern Brazil

Soil organic carbon (SOC) plays an important role for soil quality and its conservation is affected by the land-use change (LUC) associated with sugarcane (Saccharum officinarum) expansion. This study was based on the hypothesis that: (i) LUC from perennial crops (e.g., coffee and citrus) and extensive pasture to sugarcane plantation results in depletions of soil carbon (C) stock and its quality; and (ii) transition of annual crops to sugarcane increases soil C stock and improves its quality. Therefore, the objective of this study was to assess changes in soil C stocks and the humification levels of soil organic matter (SOM) upon conversion of different land uses (coffee, citrus, annual crop and pasture) into sugarcane plantation in the Mococa region, northeast of São Paulo state, southern Brazil. The experiment was conducted within commercial farms and experimental design is comprised of a farming system involving four scenarios of land-use transition to sugarcane (e.g., paired areas). Soil samples were collected to a 1-m depth (0?10,10?20, 20?60 and 60?100 cm), and the equivalent layers of 0?20 and 0?100 cm were obtained for each paired area. SOC decreased in 3 years ranged from 124.5 to 99.8 Mg C ha-1 for the 0?100 cm layer following the conversion of coffee to sugarcane. Conversion of citrus to sugarcane depleted soil C stock from 147.7 to 113.1 Mg C ha-1 for the 0?100 cm layer after a 4-year period. Conversion of pasture into sugarcane was comparatively less adverse in terms of soil C stocks, with depletion only for the 0?20 cm layer from 30.3 to 17.0 Mg C ha-1 in 8 years. Regarding the conversion from annual crop to sugarcane, there was no difference in soil C stock among land uses at any soil depths. Laser-Induced Fluorescence Spectroscopy (LIFS) showed a high stage of humification of SOM with increase in the magnitude of depletion of soil C stock, and vice versa. Increases in humification stages of SOM were observed from the top to the deepest layers for most of the land-use systems. Overall, conversions of perennial tree crops (e.g., coffee and citrus) into sugarcane increased the humification levels of SOM in sub-soil, except when sugarcane replaced pasture. The latter had lower humification of SOM in the surface layers of soil because of intensive tillage associated with sugarcane planting operations. Thus, the short-term maintenance of straw had a minor impact in improving soil C accumulation as well as reversing the increased oxidation level of SOM induced by sugarcane expansion. Further, our study suggests the need of assessing the impacts of LUC on soil C budget to deep sub-soil layers in agricultural systems. Finally, the data indicate that expansion of sugarcane over coffee and citrus agrosystems may impact the sustainability of ethanol production because of LUC-induced depletion of soil C stock and degradation of soil quality

Variação no estoque de carbono do solo na mudança do uso da terra para cana-de-açúcar em Mococa, SP, Brasil.

A mudança na cobertura e uso da terra (MUT) gerada pela expansão da cana-de-açúcar implica em relevantes alterações nos ciclos biogeoquímicos, incluindo os estoques de carbono (C) do solo, além das emissões de gases de efeito estufa (GEE). Objetivou-se, com este estudo, determinar as variações do estoque de C do solo na expansão (MUT) da cana-de-açúcar sobre áreas de pastagem e cultura anual na região de Mococa (SP), Brasil. O experimento foi conduzido em parcelas subdivididas com cinco repetições e sob delineamento inteiramente casualizado. Os tratamentos principais são em pares amostrais próximos, sendo o primeiro representado pelo uso da terra anterior à conversão e o segundo referente à cultura da cana-de-açúcar após a MUT. Os tratamentos secundários foram quatro profundidades de solo (0-10, 10-20, 20-60, 60-100 cm). A área de mata nativa apresentou o maior estoque de C no solo (228,6 Mg C ha-1), sendo muito superior comparado aos demais agrossistemas: pastagem, cana-pasto, cultura anual e cana-anual. Observa-se que a conversão de pastagem para cana-de-açúcar resultou em diferença significativa nos estoques de C do solo, de 102,3 para 76,3 Mg C ha-1 (25,4%) durante 8 anos. Em contrapartida, a variação dos estoques de C devido à conversão de cultura anual para cana-de-açúcar foi não significativa, variando de 116,2 para 121,2 Mg C ha-1 ao longo de 7 anos. Estes resultados indicam como a expansão da cana-de-açúcar impacta nesse importante aspecto e aponta para rotas de maior sustentabilidade do etanol de cana considerando-se a MUT

Correction to:Sugarcane Straw Removal: Implications to Soil Fertility and Fertilizer Demand in Brazil (BioEnergy Research, (2019), 12, 4, (888-900), 10.1007/s12155-019-10021-w)

The original version of this article was published with a wrong heading by mistake. The correct heading is Original Paper

Senna reticulata : a viable option for bioenergy production in the Amazonian region

Senna reticulata is an Amazonian tree that quickly accumulates high biomass. It grows widely in the north of Brazil occupying degraded regions and is popularly known as “matapasto” (pasture-killer) due to its aggressive colonization strategy. When its aerial parts are harvested, S. reticulata recolonizes the pasture quickly recovering biomass production. In this work, we examined the potential of S. reticulata for bioenergy production in the Amazon region and the effect of a CO2 enriched atmosphere on its biomass composition. Nearly 50% of the biomass of the aerial parts is non-structural carbohydrates (NSC). Concerning structural carbohydrates, pectins (25% and 23%), hemicelluloses (11% and 16%), and cellulose (4% and 14%) contents were very similar in leaves and stems, respectively. Lignin varied considerably among organs, being 35% in roots, 7% in stems, and 10% in leaves. Although elevated CO2 did not change significantly cell wall pools, lignin content was reduced in leaves and roots. Furthermore, starch increased 31% in leaves under elevated CO2, which improved saccharification by 47%. We conclude that Senna reticulata is a suitable species for use as a bioenergy feedstock in the tropics and specifically for remote communities in the Amazonian region