DEPOSIÇÃO DE SERAPILHEIRA E CARBONO EM PLANTIOS DE SABIÁ, ANDIROBA E FLORESTA SECUNDÁRIA

O objetivo do estudo foi avaliar o padrão de deposição anual de serapilheira, carbono orgânico (CO) e nitrogênio (N) entre as áreas de floresta secundária (FS) e plantios de sabiá (Mimosa caesalpinaefolia Benth.) e andiroba (Carapa guianenses Aubl.) (ambos os plantios com regeneração natural) na Floresta Nacional Mário Xavier, no município de Seropédica (RJ). Para a avaliação anual de deposição da serapilheira foram usados coletores circulares durante um ano (de outubro de 2006 a setembro de 2007). Os valores de aporte total de serapilheira foram 8,82, 8,35 e 6,95 Mg ha-1ano-1 para as áreas de plantio de M. caesalpinaeolia, plantio de C. guianenses e floresta secundária, respectivamente. O verão foi a única estação onde não foram observadas diferenças significativas nos aportes de serapilheira entre as áreas. As frações folha e fruto, em média, foram as que contribuíram com maior e menor aporte de material decíduo, respectivamente, nas três áreas avaliadas. Observou-se que as áreas de plantios de M. caesalpinaefolia e C. guianenses contribuíram com fluxo de CO e N para o solo via serapilheira semelhante a FS. Correlações entre as taxas de deposição serapilheira e as variáveis climáticas foram observadas apenas nas áreas de floresta secundária (correlação negativa com a temperatura e precipitação) e M. caesalpinaefolia (correlação negativa com a precipitação).

Soil organic matter fractions, chemical attributes and aggregation under forestry and agricultural systems

The aim of this work was to evaluate the influence of the conversion of forest systems to agricultural systems in the organic matter compartments, aggregation and soil chemical attributes, in the Atlantic Forest. The evaluated systems were: annual crop (ACr); perennial agriculture (PAg); pasture; and secondary forest early (SFES), medium (SFMS), and advanced stage (SFAS). Soil samples were collected at the layer of 0-5 cm depth and quantified the total organic carbon (TOC), C of humic substances, oxidizable C, granulometric fractions of soil organic matter (SOM), soil chemical attributes, soil aggregation and glomalin-related soil protein (GRSP-total and GRSP-easily extractable) in different aggregate classes. It was observed a reduction of the TOC, particulate organic carbon (POC), humic substances and oxidizable C in the PAg and ACr areas comparing to pasture and forest systems. Moreover, the pH values increased whereas P content decreased in comparison with SFAS. As for aggregation, the PAg and the ACr decreased by around 35% and 20% the mean weight diameter of aggregates, respectively, compared to the average values found in the forestry systems, and 34% and 45%, respectively in relation to pasture. In general, GRSP-total were reduced by agriculture. Thus, it appears that the agriculture which has been practiced is altering negatively the soil chemical, physical and biological attributes.The aim of this work was to evaluate the influence of the conversion of forest systems to agricultural systems in the organic matter compartments, aggregation and soil chemical attributes, in the Atlantic Forest. The evaluated systems were: annual crop (ACr); perennial agriculture (PAg); pasture; and secondary forest early (SFES), medium (SFMS), and advanced stage (SFAS). Soil samples were collected at the layer of 0-5 cm depth and quantified the total organic carbon (TOC), C of humic substances, oxidizable C, granulometric fractions of soil organic matter (SOM), soil chemical attributes, soil aggregation and glomalin-related soil protein (GRSP-total and GRSP-easily extractable) in different aggregate classes. It was observed a reduction of the TOC, particulate organic carbon (POC), humic substances and oxidizable C in the PAg and ACr areas comparing to pasture and forest systems. Moreover, the pH values increased whereas P content decreased in comparison with SFAS. As for aggregation, the PAg and the ACr decreased by around 35% and 20% the mean weight diameter of aggregates, respectively, compared to the average values found in the forestry systems, and 34% and 45%, respectively in relation to pasture. In general, GRSP-total were reduced by agriculture. Thus, it appears that the agriculture which has been practiced is altering negatively the soil chemical, physical and biological attributes

Application of Georadar in Areas with Different Vegetation Cover

ABSTRACT The Atlantic Forest degradation and fragmentation imposes the need for soil and vegetation assessments in order to estimate the environmental vulnerability of the remnants. The objective of this study was to evaluate the georadar applications in areas of Atlantic Forest under different forms of use in Pinheiral, State of Rio de Janeiro, Brazil, through penetrometer impact and ground penetrating radar (GPR). Forest fragments at different stages of regeneration, and pasture and agriculture (perennial and annual) areas were selected for study. Soil characterization was performed through measurements of soil resistance to penetration (SRP) with an impact penetrometer, and the soil properties with a ground penetrating radar (georadar). SRP increased in the forest areas at initial, medium and advanced stages from 2.0 to 2.5, 2.0 to 3.0 and 2.5 to 6.0 MPa, respectively. In the perennial and annual agriculture areas, the increase in SRP was due to differences in their mineral composition, and the lowest values found in the annual agriculture area were due to fauna activity. The employment of GPR generated information in a more rapid manner than with the use of impact penetrometer

Biological Properties and Organic Matter Dynamics of Soil in Pasture and Natural Regeneration Areas in the Atlantic Forest Biome

ABSTRACT: The removal of original vegetation for crops and pasture production and then followed by natural regeneration is a standard practice in the Atlantic Forest, which has produced patches with different degrees of degradation and regeneration across the landscape. The aim of this study was to evaluate the effects of replacement of native forest by pasture and natural regeneration of vegetation on soil and on soil organic matter (SOM) dynamics in the dry and rainy season in an Atlantic Forest fragment in Passa Vinte, Minas Gerais (MG), Brazil. Soil samples were collected in the rainy and dry season, at a depth of 0.00-0.05 m. The variables determined were total organic carbon (TOC) and particle-size fractions of SOM [particulate organic carbo

Biological Properties and Organic Matter Dynamics of Soil in Pasture and Natural Regeneration Areas in the Atlantic Forest Biome

ABSTRACT The removal of original vegetation for crops and pasture production and then followed by natural regeneration is a standard practice in the Atlantic Forest, which has produced patches with different degrees of degradation and regeneration across the landscape. The aim of this study was to evaluate the effects of replacement of native forest by pasture and natural regeneration of vegetation on soil and on soil organic matter (SOM) dynamics in the dry and rainy season in an Atlantic Forest fragment in Passa Vinte, Minas Gerais (MG), Brazil. Soil samples were collected in the rainy and dry season, at a depth of 0.00-0.05 m. The variables determined were total organic carbon (TOC) and particle-size fractions of SOM [particulate organic carbon (POC) and mineral-associated organic carbon (MOC)]; microbial activity by basal respiration (BR) and microbial biomass carbon (MBC); species richness (SR) and spore abundance (SA) of arbuscular mycorrhizal fungi (AMF); and total and easily extractable glomalin-related soil protein (T-GRSP and EE-GRSP, respectively). The conversion of native forest into pasture reduced TOC, POC, MOC, AMF-SA, T-GRSP, and EE-GRSP. However, it did not reduce MBC and BR. The fallow period in the area under natural regeneration was not long enough to restore soil TOC, POC, MOC, BR, MBC, T-GRSP, and EE-GRSP to levels approaching those observed in the forest area. Nevertheless, natural regeneration of vegetation stimulated the production of seedlings (spores) of arbuscular mycorrhizal fungi, which are important for the establishment of plant species and advance of ecological succession. Seasonality affected some of the biological soil properties and SOM dynamics

Steady State RF Fingerprinting for Identity Verification: One Class Classifier Versus Customized Ensemble

Mobile phone proliferation and increasing broadband penetration presents the possibility of placing small cellular base stations within homes to act as local access points. This can potentially lead to a very large increase in authentication requests hitting the centralized authentication infrastructure unless access is mediated at a lower protocol level. A study was carried out to examine the effectiveness of using Support Vector Machines to accurately identify if a mobile phone should be allowed access to a local cellular base station using differences imbued upon the signal as it passes through the analogue stages of its radio transmitter. Whilst allowing prohibited transmitters to gain access at the local level is undesirable and costly, denying service to a permitted transmitter is simply unacceptable. Two different learning approaches were employed, the first using One Class Classifiers (OCCs) and the second using customized ensemble classifiers. OCCs were found to perform poorly, with a true positive (TP) rate of only 50% (where TP refers to correctly identifying a permitted transmitter) and a true negative (TN) rate of 98% (where TN refers to correctly identifying a prohibited transmitter). The customized ensemble classifier approach was found to considerably outperform the OCCs with a 97% TP rate and an 80% TN rate

Epigeal Fauna and Soil Chemical Attributes in Grazing and Regeneration Areas

ABSTRACT The objective of this study was to evaluate the influence of natural pasture and spontaneous regeneration on soil chemical properties and epigeal fauna community using a secondary Atlantic Forest as reference. The study areas were located in Passa Vinte, Minas Gerais, Brazil. In each study area, pitfall traps were used to sample epigeal fauna in the dry and rainy seasons. Earth samples were collected at a depth of 0-5 cm in the dry and rainy seasons for analysis of chemical attributes. The pasture and regeneration areas showed an overall activity of epigeal fauna and functional groups similar to the forest area. However, the diversity evaluated by the Shannon and Pielou evenness indices and the total richness were lower than the observed in the forest. The best fertility attributes were observed in the forest and pasture areas

Soil organic matter fractions, chemical attributes and aggregation under forestry and agricultural systems

The aim of this work was to evaluate the influence of the conversion of forest systems to agricultural systems in the organic matter compartments, aggregation and soil chemical attributes, in the Atlantic Forest. The evaluated systems were: annual crop (ACr); perennial agriculture (PAg); pasture; and secondary forest early (SFES), medium (SFMS), and advanced stage (SFAS). Soil samples were collected at the layer of 0-5 cm depth and quantified the total organic carbon (TOC), C of humic substances, oxidizable C, granulometric fractions of soil organic matter (SOM), soil chemical attributes, soil aggregation and glomalin-related soil protein (GRSP-total and GRSP-easily extractable) in different aggregate classes. It was observed a reduction of the TOC, particulate organic carbon (POC), humic substances and oxidizable C in the PAg and ACr areas comparing to pasture and forest systems. Moreover, the pH values increased whereas P content decreased in comparison with SFAS. As for aggregation, the PAg and the ACr decreased by around 35% and 20% the mean weight diameter of aggregates, respectively, compared to the average values found in the forestry systems, and 34% and 45%, respectively in relation to pasture. In general, GRSP-total were reduced by agriculture. Thus, it appears that the agriculture which has been practiced is altering negatively the soil chemical, physical and biological attributes

Evaluation of a quality improvement intervention to reduce anastomotic leak following right colectomy (EAGLE): pragmatic, batched stepped-wedge, cluster-randomized trial in 64 countries

Background Anastomotic leak affects 8 per cent of patients after right colectomy with a 10-fold increased risk of postoperative death. The EAGLE study aimed to develop and test whether an international, standardized quality improvement intervention could reduce anastomotic leaks. Methods The internationally intended protocol, iteratively co-developed by a multistage Delphi process, comprised an online educational module introducing risk stratification, an intraoperative checklist, and harmonized surgical techniques. Clusters (hospital teams) were randomized to one of three arms with varied sequences of intervention/data collection by a derived stepped-wedge batch design (at least 18 hospital teams per batch). Patients were blinded to the study allocation. Low- and middle-income country enrolment was encouraged. The primary outcome (assessed by intention to treat) was anastomotic leak rate, and subgroup analyses by module completion (at least 80 per cent of surgeons, high engagement; less than 50 per cent, low engagement) were preplanned. Results A total 355 hospital teams registered, with 332 from 64 countries (39.2 per cent low and middle income) included in the final analysis. The online modules were completed by half of the surgeons (2143 of 4411). The primary analysis included 3039 of the 3268 patients recruited (206 patients had no anastomosis and 23 were lost to follow-up), with anastomotic leaks arising before and after the intervention in 10.1 and 9.6 per cent respectively (adjusted OR 0.87, 95 per cent c.i. 0.59 to 1.30; P = 0.498). The proportion of surgeons completing the educational modules was an influence: the leak rate decreased from 12.2 per cent (61 of 500) before intervention to 5.1 per cent (24 of 473) after intervention in high-engagement centres (adjusted OR 0.36, 0.20 to 0.64; P < 0.001), but this was not observed in low-engagement hospitals (8.3 per cent (59 of 714) and 13.8 per cent (61 of 443) respectively; adjusted OR 2.09, 1.31 to 3.31). Conclusion Completion of globally available digital training by engaged teams can alter anastomotic leak rates. Registration number: NCT04270721 (http://www.clinicaltrials.gov)