Análise dos estoques de carbono no solo sob diferentes coberturas vegetais no Brasil

Anthropic activities have caused an increase in the concentration of greenhouse gases in the atmosphere, mainly due to changes in land use that alter the ability of soils to store CO2. The present study seeks to review current publications on changes in soil carbon stock under different vegetation cover published in recent years and to make a critical and systemic assessment of the subject, considering the methodologies used in each work and the different types of soil management and use in various regions of Brazil. For data collection, 35 articles published in the last ten years that correlated with the theme were selected. The survey of the articles sought to characterize the Brazilian ecosystems and summarize the main published data on carbon stocks in ecosystems and subsequently the estimates of stocks in environments under changing land use. The results showed that the different vegetation coverings present distinct, however positive capacity to store carbon in the soil in Brazil and that variables such as management, texture, physical, chemical and biological attributes are significant factors and can and directly influence the results.Atividades antrópicas têm causado a elevação da concentração dos gases de efeito estufa na atmosfera, principalmente devido mudanças causadas no uso da terra, que alteram a capacidade dos solos em armazenar o CO2. O presente estudo busca revisar publicações atuais sobre mudanças no estoque de carbono do solo sob diferentes coberturas vegetais publicados nos últimos anos e realizar uma avaliação crítica e sistêmica do assunto, considerando as metodologias utilizadas em cada trabalho e os diferentes tipos de manejo e uso dos solos em várias regiões do Brasil. Para a coleta de dados foram selecionados 35 artigos publicados nos últimos dez anos que se correlacionavam com o tema. Feito o levantamento dos artigos buscou-se caracterizar os ecossistemas brasileiros e resumir os principais dados publicados sobre os estoques de carbono nos ecossistemas e posteriormente os as estimativas dos estoques em ambientes sob mudança uso do solo. Os resultados apontaram que as diferentes coberturas vegetais apresentam distintas, entretanto positiva capacidade em estocar carbono no solo no Brasil e que variáveis como o manejo, a textura, atributos físicos, químicos e biológicos são fatores significativos e podem e influenciam diretamente nos resultados

LITTERFALL PRODUCTION IN MANGROVE FORESTS OF THE SÃO FRANCISCO RIVER ESTUARY, SERGIPE STATE, BRAZIL

Litterfall production contributes to the flow models and carbon content essential for ecosystem dynamics. The objective of the present study was to assess litterfall production rates in the Costinha mangrove forests, São Francisco River Estuary, Sergipe state, Brazil. To this end, litterfall production in the study area was monitored in five stratified stations (A, B, C, D and E) using the same channels as dividers. Ten (10) 0.25 m2 litter collectors, totaling 120 litterbags, were allocated to each forest station for monthly monitoring lasting two years. The collected material was separated into fractions: leaf, flower, fruit, branch and twig, stipule and miscellaneous, and leaves and fruits were separated by species. The average litterfall production was 13.53 ton ha-1.year-1 in the first year and 13.21 ton ha-1.year-1 in the second year, with no statistically significant differences (p>0.05) between the years during the evaluation period. Generally, litterfall production in fractions presented the following descending order: leaves > branches and twigs > stipules > fruits and propagules > miscellaneous > flowers, with the leaf fractions accounting for 71.46% of the production. The Costinha mangrove forest showed variable litterfall production rates throughout the study period, but there was an increasing trend in leaf fall in warmer seasons

Temporal Analysis of Forest Fragmentation in the Amazon Rainforest of Tocantins State, Brazil

Abstract The Amazon Rainforest presents intense pressure from agricultural and cattle farming activities on its forest remnants, which promotes forest fragmentation. The present study aimed to quantify structural changes in the Amazon Rainforest landscape in the state of Tocantins, Brazil, that occurred between 1985 and 2020 using Mapbiomas data and landscape metrics. MAPBIOMS images were used to delimit forest fragments and size classes. Landscape metrics were estimated using the Fragstats® software. In the state of Tocantins, the Amazon Rainforest, grassland, and savanna showed a fragmentation process between 1985 and 2020, with a reduction in their total area and the number of fragments, with less rounded shapes and loss of core areas, in need of environmental policies to protect forest remnants and interrupt the process of Forest fragmentation, especially the Amazon Rainforest

FLORISTIC AND STRUCTURAL CHARACTERIZATION OF THE MANGROVE FORESTS IN THE ESTUARY OF THE SÃO FRANCISCO RIVER

The objective of this work was characterize the floristic diversity and the phytosociological structure of the mangrove in the São Francisco River estuary in order to contribute to the conservation of this ecosystem. Thirty-four sampling sites were selected, according to ongoing structural mosaic in the region ranging from 100 to 400 m between themselves, in a total useful area of 0.7625 ha. The evaluated parameters were: density of live and dead trunks; living and dead Basal Area; Absolute Frequency, Relative Frequency and Importance Value. Three typical mangrove species of the São Francisco estuary were found such as Avicennia germinans (L.) Stearn, Rhizophora mangle L. and Laguncularia racemosa (L.) Gaertn. F. Gaertn. The forest height ranged from 2.88 to 15.63 m, the DBH from 3.95 to 19.74 cm, live basal area from 4.22 to 47.83 m² ha-1 and dead basal area from 0.50 to 59.63 m² ha-1. The living trunks density ranged from 375.00 to 9100.00 trunks ha-1 and dead trunk density from 100-2800 trunks ha-1. The described results in this study demonstrated that the mangrove forests presents a structural variability that may be associated with environmental characteristics (marine erosion) and anthropogenic factors. The peculiarities of each site emphasize the importance of preventive actions in the ecosystem conservation

Riverine landscape changes: case-study of Paramopama River, Sergipe State

Os objetivos deste trabalho foram analisar as alterações da paisagem promovidas pela erosão marginal e verificar a eficácia da técnica de bioengenharia de solos na recuperação das margens de um trecho do rio Paramopama, localizado no município de São Cristóvão, estado de Sergipe. Para a avaliação da alteração da paisagem, classificada como de altíssimo, alto e baixo grau de antropização, foram analisadas séries fotográficas compreendidas no período de 1998-2008. As espécies que se estabeleceram com maior ocorrência foram as pertencentes à família Poaceae. Dentre os fatores responsáveis pela alteração da paisagem, destacaram-se a erosão e a instalação de dutos atravessando a calha do rio. No rio Paramopama, foram observados dois momentos distintos, um com altíssimo e outro com alto grau de antropização. A técnica de bioengenharia de solos mostrou-se eficiente no que se refere à recuperação da paisagem, além de prover condições para a recuperação do ecossistema ribeirinho.Palavras-chave: Margens de cursos d´água; recuperação de paisagem; antropização. AbstractRiverine landscape changes: case-study of Paramopama River, Sergipe State. This work aimed to analyze current changes caused by riverbank’s erosion, as well as to verify the effectiveness of soil bioengineering techniques on the landscape recovery applied to Paramopama River banks. In order to verify landscape’s changes, it analyzed a photographic set produced during the period of 1998-2008, which had been classified according to its degree of anthropization as very high, high and low degree. Species with higher occurrence were those belonging to botanic family of Gramineae. There were many factors to landscape change, erosion was the most important followed by disturbances caused by ducts installation across the river channel. At Paramopama River two different moments could be observed, firstly, a very high degree of anthropization followed by a high degree of anthropization. Soil bioengineering technique was efficient to landscape recovery, providing ecological conditions to ecosystem recovery.Keywords: Stream banks; landscape recovery; anthropization.This work aimed to analyze current changes caused by riverbank’s erosion, as well as to verify the effectiveness of soil bioengineering techniques on the landscape recovery applied to Paramopama River banks. In order to verify landscape’s changes, it analyzed a photographic set produced during the period of 1998-2008, which had been classified according to its degree of anthropization as very high, high and low degree. Species with higher occurrence were those belonging to botanic family of Gramineae. There were many factors to landscape change, erosion was the most important followed by disturbances caused by ducts installation across the river channel. At Paramopama River two different moments could be observed, firstly, a very high degree of anthropization followed by a high degree of anthropization. Soil bioengineering technique was efficient to landscape recovery, providing ecological conditions to ecosystem recovery

Crescimento inicial e aspectos ecofisiológicos de leguminosas florestais inoculadas com fungos micorrízicos em áreas degradadas por mineração

The objective of this work was to evaluate the growth in plant height, stem base diameter, survival rate, and ecophysiology of Acacia mangium and Mimosa caesalpiniifolia plants with and without inoculation with arbuscular mycorrhizal fungi (Rhizophagus clarus) in areas degraded by mining in the municipality of Itaporanga D’Ajuda, SE, Brazil. The experiment was conducted with plants grown with spacing of 3 × 3 m in areas degraded by sand and gravel mining in Itaporanga D’Ajuda, using plants of the species Acacia mangium and Mimosa caesalpiniifolia. Four treatments were used: Acacia mangium without AMF; Mimosa caesalpiniifolia without AMF; Acacia mangium with AMF; Mimosa caesalpiniifolia with AMF. Plants from each treatment were evaluated for plant height, stem base diameter, survival rate and ecophysiological parameters at 12 months after planting. The forest legume Mimosa caesalpiniifolia inoculated with mycorrhizal fungi (Rhizophagus clarus) presented the best results in plant height, survival rate, and photosynthetic efficiency, at twelve months after planting. Plants in the treatment with Acacia mangium without inoculation with mycorrhizal fungi (Rhizophagus clarus) had the largest stem base diameters and second highest plant heights. However, the lowest survival rate of the plants may have caused overestimation of the results of stem base diameter and plant height.O objetivo deste estudo foi avaliar o crescimento em altura, diâmetro, a taxa de sobrevivência e a ecofisiologia de Acacia mangium e Mimosa caesalpiniifolia inoculadas com  fungos micorrízicos arbusculares (Rhizophagus clarus) e sem inoculação em área degradada de mineração no município de Itaporanga D’Ajuda, SE. O experimento foi implantado no espaçamento de 3x3 m em uma área degradada por mineração de areia e cascalhos no município de Itaporanga D’Ajuda, SE com as espécies Acacia mangium (Acacia) e Mimosa caesalpiniifolia (Sabiá). Foram definidos quatro tratamentos: Acacia mangium sem FMA; Mimosa caesalpiniifolia sem FMA; Acacia mangium com FMA; Mimosa caesalpiniifolia com FMA. As plantas de cada tratamento foram avaliadas quanto à altura da planta, diâmetro da base do caule, taxa de sobrevivência e parâmetros ecofisiológicos aos 12 meses após o plantio, utilizando 5 plantas selecionadas ao acaso por tratamento. Doze meses após o plantio conclui-se: a leguminosa florestal Mimosa caesalpiniifolia inoculada com fungos micorrízicos Rhizophagus clarus apresentou os melhores resultados em altura, taxa de sobrevivência e eficiência fotossintética. A Acacia mangium sem inoculação com fungos micorrízicos Rhizophagus clarus teve o maior diâmetro e a segunda maior altura.  Porém a menor taxa de sobrevivência pode ter superestimado os resultados de diâmetro e altura

Soil organic matter and production of ears of green corn after four years under tillage systems and previous crops in costal tablelands

The current study aimed to evaluate the effects of different tillage systems on soil organic matter (SOM) contents and green corn yield (total ear weight) of an Argissolo Vermelho-Amarelo (Ultissol) in Coastal tablelands of northeast Brazil. The experiment was arranged as a strip plot design with three replications. Three tillage practices [conventional tillage (CT), minimum tillage (MT) and no-tillage (NT)] were laid out as a whole plot each (830 m²). Then, each plot was equally split into 12 experimental units (60 m²), distant 1 x 10 m from each other, where in four cover crops [pigeon pea (Cajanus cajan (L.) Millsp.), sunn hemp (Crotalaria juncea L.), beans (Phaseolus vulgaris) and peanut (Arachis hypogeae) were seedling previous to corn cultivation. Neither cover crops, nor tillage practices affected SOM contents at 0.20 m depth. An exception was observed on beans plots in which CT resulted on the lowest SOM content (8.5 dag kg-1) at 0-10 cm soil layer. Regarding green corn ears yield, CT adoption also resulted in lower weight (4.11 t ha-1) than those on NT (7.65 t ha-1), regardless of cover crop. On the other hand, the influence of cover crops on green corn yield relied upon tillage practices. Peanuts and sunn hemp performed best to improve corn yield in CT; peanuts and beans increased by 14 % the green corn ears yield in MT, while sunn hemp resulted in the highest total ear weight (9.42 t ha-1). Linear correlation of Pearson was significant for SOM and productivity green maize ears in minimum tillage beans (p <0.001; r = 0.996). After four years of absence or reduced soil disturbance, there was no increase in SOM levels. The plowing appears to be important for increasing the entry of C soil and chemical protection SOM of Argissols mainly in the surface layer of Coastal tablelands in brazilian northeast. Although the NT did not provide higher levels of SOM, the yield of green maize in commercial was significantly higher when adopting conservation systems