Sustainability, certification, and regulation of biochar

Biochar has a relatively long half-life in soil and can fundamentally alter soil properties, processes, and ecosystem services. The prospect of global-scale biochar application to soils highlights the importance of a sophisticated and rigorous certification procedure. The objective of this work was to discuss the concept of integrating biochar properties with environmental and socioeconomic factors, in a sustainable biochar certification procedure that optimizes complementarity and compatibility between these factors over relevant time periods. Biochar effects and behavior should also be modelled at temporal scales similar to its expected functional lifetime in soils. Finally, when existing soil data are insufficient, soil sampling and analysis procedures need to be described as part of a biochar certification procedure.O “biochar” tem um tempo de meia-vida no solo relativamente longo e pode alterar substancialmente as propriedades, processos e funções do solo. A perspectiva da aplicação de “biochar” aos solos, em escala global, evidencia a importância de se lhe atribuir um processo de certificação sofisticado e rigoroso. O objetivo deste trabalho foi discutir o conceito da integração das propriedades do “biochar” com os fatores ambientais e socioeconômicos relevantes do local de aplicação selecionado, como parte de um procedimento de certificação sustentável que otimize a complementaridade e a compatibilidade entre esses fatores, em períodos de tempo relevantes. Os efeitos e o comportamento do “biochar” devem, também, ser modelados em escalas temporais similares às de seu tempo de vida funcional nos solos do local selecionado. Finalmente, onde os dados existentes sobre as características do solo forem insuficientes, procedimentos de amostragem e análise do solo devem ser descritos como parte do procedimento de certificação do “biochar”.publishe

Auxinic herbicides, mechanisms of action, and weed resistance: A look into recent plant science advances

Auxin governs dynamic cellular processes involved at several stages of plant growth and development. In this review, we discuss the mechanisms employed by auxin in light of recent scientific advances, with a focus on synthetic auxins as herbicides and synthetic auxin resistance mechanisms. Two auxin receptors were reported. The plasma membrane receptor ABP1 (Auxin Binding Protein 1) alters the structure and arrangement of actin filaments and microtubules, leading to plant epinasty and reducing peroxisomes and mitochondria mobility in the cell environment. The second auxin receptor is the gene transcription pathway regulated by the SCFTir/AFB ubiquitination complex, which destroys transcription repressor proteins that interrupt Auxin Response Factor (ARF) activation. As a result mRNA related with Abscisic Acid (ABA) and ethylene are transcribed, producing high quantities of theses hormones. Their associated action leads to high production of Reactive Oxygen Species (ROS), leading to tissue and plant death. Recently, another ubiquitination pathway which is described as a new auxin signaling route is the F-box protein S-Phase Kinase-Associated Protein 2A (SKP2A). It is active in cell division regulation and there is evidence that auxin herbicides can deregulate the SKP2A pathway, which leads to severe defects in plant development. In this discussion, we propose that SFCSKP2A auxin binding site alteration could be a new auxinic herbicide resistance mechanism, a concept which may contribute to the current progress in plant biology in its quest to clarify the many questions that still surround auxin herbicide mechanisms of action and the mechanisms of weed resistance

Características dos componentes externos e das gorduras descartadas de novilhos superprecoces não-castrados ou castrados de dois genótipos terminados em confinamento

Objetivou-se com este estudo avaliar as características dos componentes externos e da gordura de descarte de novilhos de duas condições sexuais e dois genótipos terminados em confinamento. A idade e o peso médios dos animais ao início do período experimental foram de 12 meses e 267,0 kg, respectivamente. Os novilhos foram confinados até atingirem o peso de abate pré-estabelecido médio de 400 kg. A dieta foi formulada com relação volumoso:concentrado de 50:50, com base na matéria seca, com 10% de proteína bruta. O delineamento experimental utilizado foi o inteiramente casualizado, em arranjo fatorial de 2 × 2, composto de duas condições sexuais e dois grupos genéticos. O peso de corpo vazio (PCV), os rendimentos de carcaça em relação ao peso de corpo vazio e a relação entre o peso de corpo vazio e o peso de abate foram similares entre genótipos e condições sexuais. Para o peso absoluto das orelhas, observou-se interação significativa entre genótipo e condição sexual dos novilhos. Animais castrados apresentaram maiores valores de gordura intestinal em relação ao peso de corpo vazio (1,62 versus 1,18%) e ao peso ao abate (1,41 versus 1,02%) e de cabeça em relação ao peso ao abate (3,78 versus 3,29%). Os animais com predominância de sangue Charolês apresentaram maior peso absoluto de vassoura da cauda (0,16 versus 0,11 kg) e novilhos Nelore maiores pesos relativos de couro e gordura renal. Não há correlação entre o rendimento de carcaça e os componentes não-integrantes da carcaça.The objective of this study was to evaluate the characteristics of external components and discard fat of young steers with two different sexual conditions and two different genotypes, finished in feedlot. Average age and weight of the animals at the beginning of the experimental period were 12 months and 267.0 kg, respectively. The steers were in feedlot until reaching pre-established slaughter weight of 400 kg. Diet contained roughage:concentrate ratio of 50:50, on dry matter basis, with 10% crude protein. It was used a complete randomized experimental design, in a 2 × 2 factorial arrangement, composed of two sexual conditions and two genetic groups. Empty body weight (EBW), carcass dressing in relation to empty body weight and the relationship between empty body weight and slaughter weight were similar among genotypes and sexual conditions. For absolute weight of ears, it was observed significant interaction between genotypes and sexual conditions of steers. Castrated animals showed greater values of intestinal fat in relation to empty body weight (1.62 versus 1.18%). Animals with Charolais predominance showed greater absolute values to tail broom (0.16 versus 0.11 kg) and Nellore steers predominance presented greater weight related to rawhide and renal fat. There is no correlation among carcass dressing and non-integrant components of carcass