Relação entre dados de sensoriamento remoto e perdas de solo em entressulcos observadas em campo

The objective of this work was to evaluate the relationship between different remote sensing data, derived from satellite images, and interrill soil losses obtained in the field by using a portable rainfall simulator. The study was carried out in an area of a hydrographic basin, located in Médio Paraíba do Sul, in the state of Rio de Janeiro – one of the regions most affected by water erosion in Brazil. Evaluations were performed for different vegetation indices (NDVI, Savi, EVI, and EVI2) and fraction images (FI), derived from linear spectral mixture analysis (LSMA), obtained from RapidEye, Sentinel2A, and Landsat 8 OLI images. Vegetation indices are more adequate to predict soil loss than FI, highlighting EVI2, whose exponential model showed R2 of 0.74. The best prediction models are generated from the RapidEye image, which shows the highest spatial resolution among the sensors evaluated.O objetivo deste trabalho foi avaliar a relação entre diferentes dados de sensoriamento remoto, derivados de imagens de satélite, e perdas de solo em entressulcos obtidas em campo por meio de um simulador de chuvas portátil. O estudo foi realizado em uma microbacia hidrográfica localizada no Médio Paraíba do Sul, no Estado do Rio de Janeiro – uma das regiões mais afetadas por erosão hídrica no Brasil. Foram avaliados diferentes índices de vegetação (NDVI, Savi, EVI e EVI2) e frações de componentes puros (FCP), derivados de modelos lineares de mistura espectral (MLME), obtidos de imagens RapidEye, Sentinel2A e Landsat 8 OLI. Os índices de vegetação são mais adequados à predição da perda de solo do que as FCP, com destaque para o EVI2, cujo modelo exponencial apresentou R2 de 0,74. Os melhores modelos de predição são gerados a partir da imagem RapidEye, que apresenta maior resolução espacial entre os sensores avaliados

A ética do silêncio racial no contexto urbano: políticas públicas e desigualdade social no Recife, 1900-1940

Mais de meio século após o preconceito racial ter se tornado o principal alvo dos movimentos urbanos pelos direitos civis nos Estados Unidos e na África do Sul, e décadas depois do surgimento dos movimentos negros contemporâneos no Brasil, o conjunto de ferramentas legislativas criado no Brasil para promover o direito à cidade ainda adere à longa tradição brasileira de silêncio acerca da questão racial. Este artigo propõe iniciar uma exploração das raízes históricas desse fenômeno, remontando ao surgimento do silêncio sobre a questão racial na política urbana do Recife, Brasil, durante a primeira metade do século XX. O Recife foi eé um exemplo paradigmático do processo pelo qual uma cidade amplamente marcada por traços negros e africanos chegou a ser definida política e legalmente como um espaço pobre, subdesenvolvido e racialmente neutro, onde as desigualdades sociais originaram na exclusão capitalista, e não na escravidão e nas ideologias do racismo científico. Neste sentido, Recife lança luzes sobre a política urbana que se gerou sob a sombra do silêncio racial.More than half a century after racial prejudice became central to urban civil rights movements in the United States and South Africa, and decades after the emergence of Brazil’s contemporary Black movements, Brazil's internationally recognized body of rights-to-the-city legislation still adheres to the country's long historical tradition of racial silence. This article explores the historical roots of this phenomenon by focusing on the emergence of racial silence in Recife, Brazil during the first half of the 20th Century. Recife was and remains a paradigmatic example of the process through which a city marked by its Black and African roots came to be legally and politically defined as a poor, underdeveloped and racially neutral space, where social inequalities derived from capitalist exclusion rather than from slavery and scientific racism. As such, Recife'sexperience sheds light on the urban policies that were generated in the shadow of racial silence

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

FRAÇÕES GRANULOMÉTRICAS E OXIDÁVEIS DA MATÉRIA ORGÂNICA EM SISTEMAS DE COLHEITA DE CANA - DE - AÇÚCAR

The systems of harvesting sugar cane can cause changes in fertility, quantity and quality of organic matter and the degree of oxidation, altering soil carbon stocks. Given this context, the objective was to evaluate the production of dry biomass (DB), soil fertility, the content of total organic carbon (TOC), the car- bon in particle size fractions (particulate organic carbon (COp) and organic carbon associated with minerals (COam)) and oxidizable organic matter fractions (F1, F2, F3, F4 and F1 / F4) in manual harvesting (CMa) and mechanized (CMe) of sugar cane. The sampling for biomass production was conducted in area of 1 m 2 at four points per plot, soil samples were collected at depths of 0.00 - 0.05; 0.05 - 0.10; 0.10 - 0.20 and 0.20 - 0.40 m. The average annual production of dry biomass in the area CMe was 17 times higher when compared to the area of CMa; The pH and phosphorus content was significantly lower in the larger depths area CMa when compared with that of Cme; the harvesting system caused significant CMe in TOC, COp and COam depth 0.00 - 0.05 m increases when compared to the CMa system; There were not significant differences in the oxidizable fractions (F1, F2, F3 and F4) of the organic carbon in the areas of CMa and CMe

Relationship between remote sensing data and field-observed interril erosion

<div><p>Abstract: The objective of this work was to evaluate the relationship between different remote sensing data, derived from satellite images, and interrill soil losses obtained in the field by using a portable rainfall simulator. The study was carried out in an area of a hydrographic basin, located in Médio Paraíba do Sul, in the state of Rio de Janeiro - one of the regions most affected by water erosion in Brazil. Evaluations were performed for different vegetation indices (NDVI, Savi, EVI, and EVI2) and fraction images (FI), derived from linear spectral mixture analysis (LSMA), obtained from RapidEye, Sentinel2A, and Landsat 8 OLI images. Vegetation indices are more adequate to predict soil loss than FI, highlighting EVI2, whose exponential model showed R2 of 0.74. The best prediction models are generated from the RapidEye image, which shows the highest spatial resolution among the sensors evaluated.</p></div

Carbono, matéria orgânica leve e frações oxidáveis do carbono orgânico sob diferentes sistemas de produção orgânica

The evaluation of water light organic matter and organic carbon fractioning by different oxidation degrees may contribute to the soil organic matter dynamics understanding in areas under organic management. This study aimed to evaluate the total soil organic carbon (TOC), light organic matter (LOM) in water and TOC oxidizable fractions under different organic production systems. It was selected five areas: fig cultivation, passion fruit and Desmodium sp consortium; corn/beans cultivation in conventional tillage (CT), eggplant/corn cultivation in no-tillage (NT) and agroforest system (AFS). The soil samples were collected at 0-0.05 and 0.05-0.10 m depths, and TOC, LOM in water and organic carbon oxidizable (fractions F1, F2, F3 and F4) were evaluated. The fig area showed higher TOC and N contents. The highest levels of LOM in water were observed in NT and the lowest in CT area. The highest C contents of F1 were observed in fig and passion fruit areas (0-0,05 m). For F4, the Fig and NT areas showed the C highest values (0-0.05 m). In a general way, in the fig area it was observed an increasing of TOC and N contents when compared with others areas. The NT area promot the highest LOM and N contents when compared to the CT system. The organic farming system in no-tillage with eggplant/corn provides better carbon distribution in each oxidizable fraction in relation to the TOC, showing a balance between more lability (F1) soil organic matter and more recalcitrant organic matter fraction (F4).A avaliação da matéria orgânica leve em água e o fracionamento do carbono orgânico por diferentes graus de oxidação podem contribuir para o entendimento da dinâmica da matéria orgânica do solo em áreas sob manejo orgânico. Este trabalho teve como objetivo avaliar o carbono orgânico total (COT) do solo, a matéria orgânica leve (MOL) em água e frações oxidáveis do COT sob diferentes sistemas de produção orgânica. Foram selecionadas cinco áreas: cultivo de figo, consórcio maracujá - Desmodium sp.; cultivo de milho/feijão, com preparo convencional (PC) do solo; cultivo de berinjela/milho, em sistema plantio direto (SPD) e um sistema agroflorestal (SAF). Foram coletadas amostras de solo nas profundidades de 0-0,05 e 0,05-0,10 m, sendo avaliados o COT, a MOL em água e carbono orgânico oxidável (frações F1, F2, F3 e F4). A área de figo apresentou os maiores teores de COT e N. Os maiores teores de MOL foram observados na área em SPD, sendo os menores verificados na área em PC do solo. Os maiores teores de C da F1 foram encontrados nas áreas de figo e maracujá (0-0,05 m). Para a F4, as áreas de Figo e SPD apresentaram os maiores valores de C (0-0,05 m). De maneira geral, o sistema de uso do solo com figo está aumentando os teores de COT e N em detrimento aos demais. A área sob SPD favorece maiores teores de MOL e N quando comparado ao PC. O cultivo orgânico em sistema plantio direto com berinjela/milho propicia melhor distribuição do carbono de cada fração oxidável em relação ao COT, apresentando um equilíbrio entre matéria orgânica de maior labilidade no solo (F1) e matéria orgânica mais recalcitrante (F4).   Carbon, light organic matter and oxidizable organic carbon fractionsin different organic production systems AbstractThe evaluation of water light organic matter and organic carbon fractioning by different oxidation degrees may contribute to the soil organic matter dynamics understanding in areas under organic management. This study aimed to evaluate the total soil organic carbon (TOC), light organic matter (LOM) in water and TOC oxidizable fractions under different organic production systems. It was selected five areas: fig cultivation, passion fruit and Desmodium sp consortium; corn/beans cultivation in conventional tillage (CT), eggplant/corn cultivation in no-tillage (NT) and agroforest system (AFS). The soil samples were collected at 0-0.05 and 0.05-0.10 m depths, and TOC, LOM in water and organic carbon oxidizable (fractions F1, F2, F3 and F4) were evaluated. The fig area showed higher TOC and N contents. The highest levels of LOM in water were observed in NT and the lowest in CT area. The highest C contents of F1 were observed in fig and passion fruit areas (0-0,05 m). For F4, the Fig and NT areas showed the C highest values (0-0.05 m). In a general way, in the fig area it was observed an increasing of TOC and N contents when compared with others areas. The NT area promot the highest LOM and N contents when compared to the CT system. The organic farming system in no-tillage with eggplant/corn provides better carbon distribution in each oxidizable fraction in relation to the TOC, showing a balance between more lability (F1) soil organic matter and more recalcitrant organic matter fraction (F4).   

Evolução e acúmulo de c-co2 em diferentes sistemas de produção agroecológica

A evolução de C-CO2 por meio da atividade microbiana do solo pode ser utilizada como parâmetro para evidenciar diferenças em sistemas de produção agroecológica. Este trabalho teve como objetivo avaliar a atividade microbiana do solo por meio da evolução de C-CO2 (carbono mineralizável) oriundo da respiração dos microorganismos sob diferentes sistemas de produção. Foram selecionadas cinco áreas:cultivo de figo; consórcio maracujá – Desmodium sp.; cultivo de milho/feijão, com preparo convencional (PC) do solo; cultivo de berinjela/milho, em sistema plantio direto (PD) e um sistema agroflorestal (SAF). Foram coletadas amostras de solo nas profundidades de 0-0.05 m e 0.05 - 0.10 m, sendo avaliada a evolução de C-CO2 em laboratório e o acúmulo de C-CO2 durante 37 dias. Logo após a incubação, todos os sistemas avaliados apresentaram picos de C-CO2, com variações desses picos mais acentuadas até o 9º dia. Aos 21 dias verificou-se a estabilização da atividade microbiana. O cultivo de figo acarretou em maiores picos de evolução de C-CO2 e, também maiores acúmulos ao final dos 37 dias. A área cultivada sob PD manejado agroecologicamente apresentou menor acúmulo de C-CO2. O PC do solo acarretouem menores picos de C-CO2 em 0.05-0.10 m.The C-CO2 evolution via soil microbial activity can be used as a parameter to highlight differ-ences in agroecological production systems.  This work aimed to evaluate the microbial activity of soil through the evolution of C-CO2 (mineralizable carbon) from the respiration of microor-ganisms under different production systems.  Was selected five areas: cultivation of fig; passion fruit consortium - Desmodium sp.; cultivation of corn/beans, with conventional tillage (CT) of the soil, cultivation of eggplant/corn under no-tillage (NT) and agroforestry system (AFS).  Soil samples were collected at depths of 0.0 - 0.05 and 0.05 - 0.10 m, and was assessed microbial activity (C-CO2 evolution in the laboratory) and the accumulation of C-CO2 for 37 days.  Soon after hatching, all systems evaluated showed peaks of C-CO2, with variations of these peaks more pronounced until the 9th day of evaluation.  At 21 days there is stabilization of microbial activity.  Growing fig resulted in higher peaks of C-CO2 evolution, and also higher accumulations at the end of the 37 day trial. The acreage under NT agroecological showed lower accumulation of C-CO2. The conventional tillage resulted in lower peak C-CO2 at a depth of 5-10 cm.A evolução de C-CO2 por meio da atividade microbiana do solo pode ser utilizada como parâmetro para evidenciar diferenças em sistemas de produção agroecológica. Este trabalho teve como objetivo avaliar a atividade microbiana do solo por meio da evolução de C-CO2 (carbono minera-lizável) oriundo da respiração dos microorganismos sob diferentes sistemas de produção. Foram selecionadas cinco áreas: cultivo de figo; consórcio maracujá – Desmodium sp.; cultivo de mi-lho/feijão, com preparo convencional (PC) do solo; cultivo de berinjela/milho, em sistema plantio direto (PD) e um sistema agroflorestal (SAF). Foram coletadas amostras de solo nas profun-didades de 0-0.05 m e 0.05 - 0.10 m, sendo avaliada a evolução de C-CO2 em laboratório e o acúmulo de C-CO2 durante 37 dias. Logo após a incubação, todos os sistemas avaliados apre-sentaram picos de C-CO2, com variações desses picos mais acentuadas até o 9º dia. Aos 21 dias verificou-se a estabilização da atividade microbiana. O cultivo de figo acarretou em maiores picos de evolução de C-CO2 e, também maiores acúmulos ao final dos 37 dias. A área cultivada sob PD manejado agroecologicamente apresentou menor acúmulo de C-CO2. O PC do solo acarretou em menores picos de C-CO2 em 0.05-0.10