Quantifying soil carbon stocks and greenhouse gas fluxes in the sugarcane agrosystem: point of view

Strategies to mitigate climate change through the use of biofuels (such as ethanol) are associated not only to the increase in the amount of C stored in soils but also to the reduction of GHG emissions to the atmosphere.This report mainly aimed to propose appropriate methodologies for the determinations of soil organic carbon stocks and greenhouse gas fluxes in agricultural phase of the sugarcane production. Therefore, the text is a piece of contribution that may help to obtain data not only on soil carbon stocks but also on greenhouse gas emissions in order to provide an accurate life cycle assessment for the ethanol. Given that the greenhouse gas value is the primary measure of biofuel product quality, biorefiners that can show a higher offset of their product will have an advantage in the market place

Soil structure and greenhouse gas production differences between row and interrow positions under no-tillage

No-tillage in Brazil is an efficient agricultural system that improves crop productivity whilst controlling erosion caused to the soil by degradation. However, there is some concern regarding soil compaction. Our objective was to determine whether the function of soil structure in sustaining crop growth was dependent on row and interrow positions in long-term no-tillage. We took soil samples from a field in a commercial farm under long-term no-tillage since 1979 on a clayey Oxisol in Southern Brazil. We assessed soil physical quality using the revised Peerlkamp technique and measured bulk density, air-filled porosity and air permeability of intact soil cores. Samples were incubated to assess in vitro N2O and CO2 production. The soil physical and structural properties showed consistent differences between interrow and row positions, where the properties measured were more favorable. The revised Peerlkamp technique proved as efficient as quantitative parameters in discriminating treatment differences. Overall, soil physical conditions in the interrow were less favourable than in the row. Pore continuity did not vary as regards position. This may explain why row position did not influence in vitro N2O and CO2 production. Soil physical quality under no-tillage system is enhanced, at least in the short term, by superficial disturbances in the row as a result of the action of the coulters of the no-tillage seeder

Dextrin

Dextrins are low-molecular-weight carbohydrates produced by partial hydrolysis of glycogen or starch achieved by applying dry heat under acidic conditions (pyrolysis or roasting) and/or using enzymes (amylases), malting or mashing. Dextrin is thus a glucose-containing saccharide polymer having the same general formula of starch, but smaller and less complex. Depending on the source and on how it is digested, it can exhibit different structural features (linear, branched, or cyclic) and properties such as hygroscopicity, fermentability, sweetness, stability, gelation, solubility, bioavailability, and molecular compositions. Among starch-derived materials, dextrin is widely used in a variety of applications, namely, adhesives in the manufacture of gummed tapes, textiles and paper, as moisturizing component in cosmetics, or in the food industry. However, its biocompatibility and biodegradability combined with its low cost, abundance, and availability in medical grade make dextrin an excellent polymer for biomedical applications. In this entry, we present an overview of biomedical applications of linear dextrins. The potential of dextrin as tissue engineering scaffolds, hydrogels, drug delivery systems, excipient in tablets, or nanomedicines are thoroughly discussed in this entry.C.G., S.M., V.C. and D.S. were supported by the grants SFRH/BPD/70524/2010, SFRH/BPD/64726/2009, SFRH/ BPD/73850/2010 and SFRH/BD/64571/2009, respectively, from Fundação para a Ciência e Tecnologia (FCT), Portugal. We thank FCT funding through EuroNanoMed ENMED/0002/2010.info:eu-repo/semantics/publishedVersio

Emissão de óxido nitroso com a aplicação de dejetos líquidos de suínos em solo sob plantio direto Nitrous oxide emissions following pig slurry application in soil under no-tillage system

O objetivo deste trabalho foi comparar as emissões de óxido nitroso (N2O) para a atmosfera depois da aplicação de dejetos líquidos de suínos, em plantio direto (PD) e preparo reduzido (PR) do solo. O delineamento experimental utilizado foi o de blocos inteiramente casualizados com cinco repetições. Os tratamentos consistiram na aplicação (40 m³ ha-1), ou não, de dejetos líquidos em PD e PR. As emissões de N2O foram medidas in situ depois da aplicação dos dejetos, por 28 dias. Os fluxos de N2O aumentaram com a aplicação dos dejetos e, em apenas 20% das avaliações realizadas, foram superiores no PD. As emissões de N2O relacionaram-se com o aumento do espaço poroso ocupado pela água. Quantidades acumuladas de N na forma de N2O, emitidas em 28 dias, representaram 0,20 e 0,25% do N total aplicado com os dejetos no PD e PR, respectivamente. Os resultados demonstram que a aplicação de dejetos líquidos de suínos em PD não aumenta a emissão acumulada de N2O em relação à aplicação em PR.<br>The objective of this work was to compare nitrous oxide (N2O) emissions to the atmosphere with pig slurry application on soil under no-tillage (NT) and minimum tillage (MT). The experimental design was set as a completely randomized design with five replications. The treatments consisted of the application (40 m³ ha-1), or not, of pig slurry in NT and MT. The N2O emissions were measured in situ, after the slurry application, for 28 days. The N2O flux increased with the application of slurry and, only in 20% of the evaluations, they were greater in NT. Nitrous oxide emissions were related to the increase of the water-filled pore space. Amounts of N-N2O emitted in 28 days represented 0.20 and 0.25% of total N applied with slurry for NT and MT, respectively. Results work show that pig slurry application in NT does not increase the accumulated N2O emission in relation to application in MT