Número de esporos de fungos micorrízicos arbusculares após trituração de pousio melhorado.

Essa pesquisa teve como objetivo avaliar o efeito da adubação verde no número de esporos de fungos micorrízicos arbusculares, em área de recuperação da fertilidade do solo de agricultor familiar no município de Igarapé-Açu. O delineamento experimental utilizado foi inteiramente ao acaso, com quatro repetições. Os tratamentos consistiram em diferentes adubos verdes oriundos de pousios compostos por plantios puros de acácia, guandu, ingá e titônia, adubados ou não com fosfato de rocha, como referência teve-se o crescimento da regeneração natural. O número de esporos foi obtido por meio da contagem de esporos viáveis com o auxílio de um microscópio estereoscópico. Não foram identificadas diferenças significativas entre os tratamentos testados em nenhuma profundidade avaliada. Esses valores sugerem que o manejo conservacionista do solo auxilia na melhoria das condições do solo, ocasionando efeito indiferente dos tratamentos de adubação verde sobre o número de esporos no solo

Scaling of variables and the relation between noncommutative parameters in Noncommutative Quantum Mechanics

We consider Noncommutative Quantum Mechanics with phase space noncommutativity. In particular, we show that a scaling of variables leaves the noncommutative algebra invariant, so that only the self-consistent effective parameters of the model are physically relevant. We also discuss the recently proposed relation of direct proportionality between the noncommutative parameters, showing that it has a limited applicability.Comment: Revtex4, 4 pages; version to match the published on

First transgenic geminivirus-resistant plant in the field.

Bean golden mosaic virus (BGMV) belongs to the genus Begomovirus, whose genome is composed of two single-stranded DNA molecules, designated DNA-A and DNA-B, both of which are essential for infectivity. BGMV is transmitted by the whitefly Bemisia tabaci (Gennadius) in a persistent, circulative manner, causing golden mosaic in common bean. This disease is characterized by yellow-green mosaic of leaves, stunted growth and distorted pods, which may vary among genotypes

Conversion from forests to pastures in the Colombian Amazon leads to contrasting soil carbon dynamics depending on land management practices

This is the author accepted manuscript. The final version is available from Wiley via the DOI in this recordStrategies to mitigate climate change by reducing deforestation and forest degradation (e.g. REDD+) require country- or region-specific information on temporal changes in forest carbon (C) pools to develop accurate emission factors. The soil C pool is one of the most important C reservoirs, but is rarely included in national forest reference emission levels due to a lack of data. Here, we present the soil organic C (SOC) dynamics along 20 years of forest-to-pasture conversion in two subregions with different management practices during pasture establishment in the Colombian Amazon: high-grazing intensity (HG) and low-grazing intensity (LG) subregions. We determined the pattern of SOC change resulting from the conversion from forest (C3 plants) to pasture (C4 plants) by analysing total SOC stocks and the natural abundance of the stable isotopes (13) C along two 20-year chronosequences identified in each subregion. We also analysed soil N stocks and the natural abundance of (15) N during pasture establishment. In general, total SOC stocks at 30 cm depth in the forest were similar for both subregions, with an average of 47.1 ± 1.8 Mg C ha(-1) in HG and 48.7 ± 3.1 Mg C ha(-1) in LG. However, 20 years after forest-to-pasture conversion SOC in HG decreased by 20%, whereas in LG SOC increased by 41%. This net SOC decrease in HG was due to a larger reduction in C3-derived input and to a comparatively smaller increase in C4-derived C input. In LG both C3- and C4-derived C input increased along the chronosequence. N stocks were generally similar in both subregions and soil N stock changes during pasture establishment were correlated with SOC changes. These results emphasize the importance of management practices involving low-grazing intensity in cattle activities to preserve SOC stocks and to reduce C emissions after land-cover change from forest to pasture in the Colombian Amazon.This study was funded by AXA Research Fund (2012‐Doc‐University‐of‐Exeter‐NAVARRETE‐D)