Postharvest nitrous oxide emissions from a subtropical oxisol as influenced by summer crop residues and their management Emissão de óxido nitroso do solo no periodo pós-colheita alterada pelos resíduos das culturas de verão e seu manejo em latossolo do sul do Brasil

Nitrous oxide (N2O) is the most important non-CO2 greenhouse gas and soil management systems should be evaluated for their N2O mitigation potential. This research evaluated a long-term (22 years) experiment testing the effect of soil management systems on N2O emissions in the postharvest period (autumn) from a subtropical Rhodic Hapludox at the research center FUNDACEP, in Cruz Alta, state of Rio Grande do Sul. Three treatments were evaluated, one under conventional tillage with soybean residues (CTsoybean) and two under no-tillage with soybean (NTsoybean) and maize residues (NTmaize). N2O emissions were measured eight times within 24 days (May 2007) using closed static chambers. Gas flows were obtained based on the relations between gas concentrations in the chamber at regular intervals (0, 15, 30, 45 min) analyzed by gas chromatography. After soybean harvest, accumulated N2O emissions in the period were approximately three times higher in the untilled soil (164 mg m-2 N) than under CT (51 mg m-2 N), with a short-lived N2O peak of 670 mg m-2 h-1 N. In contrast, soil N2O emissions in NT were lower after maize than after soybean, with a N2O peak of 127 g m-2 h-1 N. The multivariate analysis of N2O fluxes and soil variables, which were determined simultaneously with air sampling, demonstrated that the main driving variables of soil N2O emissions were soil microbial activity, temperature, water-filled pore space, and NO3- content. To replace soybean monoculture, crop rotation including maize must be considered as a strategy to decrease soil N2O emissions from NT soils in Southern Brazil in a Autumn.<br>O óxido nitroso (N2O) é o mais importante gás de efeito estufa excetuando o CO2, e os sistemas de manejo devem ser avaliados quanto ao potencial de mitigação da emissão desse gás. O presente estudo foi realizado em experimento de longa duração (22 anos) e teve como objetivo avaliar o efeito de sistemas de manejo nas emissões de N2O no período pós-colheita (outono) em um Latossolo Vermelho distrófico típico situado na Fundação Centro de Experimentação e Pesquisa Fecotrigo (FUNDACEP), Cruz Alta, RS. Três sistemas de manejo foram avaliados: um em preparo convencional com resíduos de soja (PCsoja) e dois outros em plantio direto com resíduos de soja (PDsoja) e de milho (PDmilho). As emissões de N2O foram medidas em oito coletas de amostras de ar no período de 24 dias (maio de 2007), usando o método da câmara estática. Os fluxos foram obtidos pela relação entre as concentrações de gases dentro da câmara em intervalos regulares (0, 15, 30 e 45 min), analisada por cromatografia gasosa. Sobre os resíduos de soja, as emissões de N2O no período avaliado foram aproximadamente três vezes superiores no solo em PD (164 mg m-2 de N) do que em PC (51 mg m-2 de N), atingindo pico máximo de curta duração de emissão de 670 mg m-2 h-1 de N. Por outro lado, sobre os resíduos de milho, o solo em PD apresentou uma emissão inferior (34 mg m-2 de N) do que após soja, atingindo valor máximo de 127 mg m-2 h-1 de N. Variáveis de solo foram avaliadas simultaneamente às coletas de gases, e a análise multivariada dos resultados indicou que as principais variáveis controladoras da emissão de N2O foram a atividade microbiana, a temperatura, a porosidade preenchida por água e o teor de NO3- no solo. A inclusão do milho na rotação de culturas deve ser adotada em substituição à monocultura de soja como estratégia de redução da emissão outonal de N2O em solos sob plantio direto do Sul do Brasil

Mitochondrial respiratory states and rates: Building blocks of mitochondrial physiology (Part 1)

Supporting co-authors: Bakker BM, Bernardi P, Boetker HE, Borsheim E, Borutaitė V, Bouitbir J, Calbet JA, Calzia E, Chaurasia B, Clementi E, Coker RH, Collin A, Das AM, De Palma C, Dubouchaud H, Durham WJ, Dyrstad SE, Engin AB, Fornaro M, Gan Z, Garlid KD, Garten A, Gourlay CW, Granata C, Haas CB, Haavik J, Haendeler J, Hand SC, Hepple RT, Hickey AJ, Hoel F, Jang DH, Kainulainen H, Khamoui AV, Klingenspor M, Koopman WJH, Kowaltowski AJ, Krajcova A, Lane N, Lenaz G, Malik A, Markova M, Mazat JP, Menze MA, Methner A, Neuzil J, Oliveira MT, Pallotta ML, Parajuli N, Pettersen IKN, Porter C, Pulinilkunnil T, Ropelle ER, Salin K, Sandi C, Sazanov LA, Silber AM, Skolik R, Smenes BT, Soares FAA, Sokolova I, Sonkar VK, Swerdlow RH, Szabo I, Trifunovic A, Thyfault JP, Valentine JM, Vieyra A, Votion DM, Williams C, Zischka HAs the knowledge base and importance of mitochondrial physiology to human health expand, the necessity for harmonizing nomenclature concerning mitochondrial respiratory states and rates has become increasingly apparent. Clarity of concept and consistency of nomenclature are key trademarks of a research field. These trademarks facilitate effective transdisciplinary communication, education, and ultimately further discovery. Peter Mitchell’s chemiosmotic theory establishes the link between vectorial and scalar energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theory and nomenclature for mitochondrial physiology and bioenergetics. Herein, we follow IUPAC guidelines on general terms of physical chemistry, extended by considerations on open systems and irreversible thermodynamics. We align the nomenclature and symbols of classical bioenergetics with a concept-driven constructive terminology to express the meaning of each quantity clearly and consistently. In this position statement, in the frame of COST Action MitoEAGLE, we endeavour to provide a balanced view on mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately support the development of databases of mitochondrial respiratory function in species, tissues, and cells.We thank M. Beno for management assistance. Supported by COST Action CA15203 MitoEAGLE and K-Regio project MitoFit (E.G.).N