ABSTRACT Afforestation of sites disturbed after bauxite mining is the favorite technique to restore all ecosystem functions. The nature of the tree species used for revegetation of post-mining land can accelerate the recovery of soil organic matter and nutrient cycles. This study aimed to determine the litterfall production, decomposition rate and nutrient content from three types of forest cover ( Eucalyptus , Anadenanthera peregrina , mixed plantation of 16 native species) planted in a bauxite mining area in recovery. Litterfall production was evaluated monthly over 30 months, and the litter mass was assessed twice a year (dry and rainy periods). Total nutrient content was determined from samples grouped by period (dry and rainy). The annual average values for litterfall dry mass and litter mass were higher in Eucalyptus and mixed native. The period (dry or rainy) did not influence litterfall rates in A. peregrina , but Eucalyptus and mixed native presented higher amounts for litterfall during the rainy and dry periods, respectively. Litter accumulation in Eucalyptus was not affected by the season of the year, but mixed native and A. peregrina presented higher litter accumulation in the dry season. Apparent decomposition rates of A. peregrina and mixed native were higher in the rainy season, highlighting the A. peregrina with the highest values compared with the other forest covers. The mixed native presented the highest leaf content of P, K, Ca and Mg in both the litterfall and litter mass, while Eucalyptus had the lowest P, K, Ca, S and N content and the highest C content in the litterfall. Litterfall production is important in degraded areas to ensure the nutrient return to the soil. The data obtained suggest that the cultivation of a mixed of 16 native trees contribute for produce the higher annual litterfall yields, besides produces leaf litterfall of better nutritional quality in relation to P, K, Ca, Mg and S. Therefore, mixed of native trees can be a promising option for reactivation of nutrient cycling and organic matter formation in mined area of bauxite in the Brazilian Atlantic Forest.

ABSTRACT Mining is a significant driver of soil mobilization, which impacts its physical, chemical, and biological properties. Changes in land-use affect the distribution of organic matter fractions in stable aggregates, a process that is still poorly understood, especially in drastically altered areas. Recovering and monitoring soil quality to ensure the sustainable development of agricultural crops in these areas after mining is challenging. This study aimed to evaluate the influence of agronomic practices in soil rehabilitation in a bauxite-mined area after three years of field experiment installations through an assessment of organic properties in soil and aggregate classes; an attempt was also made at proposing and elaborating a Soil Quality Index (SQI), which encompasses the soil’s physical, chemical, and organic properties. Different combinations of fertilization treatments and ground cover plants intercropping with coffee were evaluated as rehabilitation practices. The results showed that after three years of rehabilitation, when organic (OF), chemical (CF), and OF+CF fertilizers were applied to the areas of coffee intercropped with Brachiaria (B), they provided higher C and N contents to the soil and aggregates classes, as well as the compartments of soil organic matter (SOM). The minimum set of soil quality indicators for reclaimed bauxite-mined areas was composed of organic indicators: labile organic carbon (LOC) and mineral-associated organic matter (C-MOM); chemical indicators including pH and effective cation-exchange capacity (t), and physical indicators such as the bulk density (BD) and stable aggregates index in water (SAIW). The t and pH were the variables most sensitive to the management systems implanted during the rehabilitation of the mined area, and, therefore, were considered the best indicators of soil quality. Brachiaria was the cover plant that contributed most to improving the soil quality of mined bauxite areas by increasing the SQI, especially when fertilized. In general, when applied to the Brachiaria, the OF+CF fertilization presented a SQI of 0.78, differing statistically from that of the natural vegetation (1.00). Fertilizers and cover crops in association with coffee in the bauxite-mined areas improved the physical, chemical, and organic properties of the soil, thus representing a viable option for reconditioning mineral exploration areas.

Abstract The use of natural antimicrobial additives, such as orange essential oil (OO), can be a promising possibility to increase food shelf life with the aid of active packaging. This study aimed to develop an active packaging using orange oil and PBAT - poly (butylene adipate co- terephthalate) to store mozzarella cheese produced by a fine film extruder with 5, 10, and 15% OO (w/w). In the results, D-limonene was oil’s main constituent with antimicrobial activity against E. aerogenes, E. coli, and S. aureus. The addition of the oil did not alter the thermal stability of the film. The water vapor permeability increased with increasing oil concentration. All films presented high strength. However, films with higher OO concentrations favored the degradation process, as observed in the activation energy. The active packaging added with 15% OO (PBAT15) was efficient, reducing microbial growth up to 6 days of storage of mozzarella cheese.

ABSTRACT Understanding soil organic matter (SOM) dynamics in production systems on tropical soils is necessary to guide strategies to increase SOM formation. This study aimed to evaluate soil carbon (C) dynamics by combining applications of different plant residues used on tropical soils. An incubation study was carried out with and without adding millet (Pennisetum americanum) residues combined with six crop residues (legumes and non-legumes); and one additional treatment with only millet residue. Higher C-CO2 fluxes recorded in jack bean, sunflower and velvet bean residues were correlated with high soluble compound contents (49.5, 49.6 and 32.1 %, respectively). Adding millet residues resulted in positive PE for all residue combinations. Soils without millet, except jack bean, had a negative PE. Residues application promoted four times increase in C-POM content (from 1.04 to 4.2 g kg-1 soil). The C-MAOM content had 2.4 times increase, being more expressive due to its high initial content (from 15.3 to 37.3 g kg-1 soil). The comparison between the final C contents in the SOM fractions showed a significant increase of 8.8 times for MAOM in relation to POM, demonstrating the larger dimension of this C reservoir in the soil. Both combinations of legumes + non-legumes and non-legume + non-legume contributed significantly to the conversion of C to MAOM. The results give insight into possible management strategies for significant C increments in the more stable SOM fractions, depending on the residue type (quality) and residue combination.

ABSTRACT: Accidents related to the rupture of iron ore tailings dams have dramatically impacted on the Brazilian natural ecosystem. So, the development of strategies to recover soil organic matter levels and build-up Technosols are required. This study aimed to evaluate the effect of N-mineral and -organic fertilization and the rhizospheric effect on soil organic matter mineralization from Technosols built under iron ore tailings. The experiment was carried out in a greenhouse; we used a factorial scheme 2 × 2 × 3: without and with the plant Crotalaria juncea ; without and with mineral fertilization; and three different organic fertilization (without organic fertilization, sewage sludge, and household waste composting), with four randomized blocks. The experimental units were PVC columns installed with a top layer of iron ore tailing from a dam, where gases were sampled to determine the CO2-C, CH4-C concentrations, and CO2-δ13C. The organic fertilization promoted a positive priming effect of 184 %. However, with mineral fertilization, no effect was observed in soil derived-CO2-C accumulated and priming effect. Similarly to non-planted soil, the planted soils with mineral and organic fertilization promoted a steady reduction in soil derived-CO2-C accumulated and rhizosphere priming effect. The soil with mineral fertilization improved in 5.52 and 0.45 g per column the shoot and root dry matter of Crotalaria when compared to the soil without mineral fertilization. In summary, the organic fertilization in Technosols built over iron ore tailings dams during revegetation was not enough to ensure the plant development and preservation of soil organic matter. However, the combination of mineral and organic fertilization promoted negative rhizosphere priming effect and a significant increase in plant biomass.

RESUMO As embalagens têm como função básica proteger o alimento e garantir a sua integridade comercial. Podem ser produzidas a partir de materiais biodegradáveis com funcionalidades específicas, tais como ação antimicrobiana e antioxidante. Além disso, pesquisas vêm sendo desenvolvidas de modo a substituir os aditivos sintéticos por outros naturais, como os extratos vegetais, devido aos compostos químicos presentes em suas misturas. O poli(butileno adipato co-tereftalato) - (PBAT) vem sendo extensivamente estudado como uma possível substituição aos polímeros convencionais devido à sua biodegradabilidade. Desse modo, o objetivo desse trabalho foi avaliar as potencialidades dos extratos vegetais de jurema preta (Mimosa tenuiflora) e cajueiro (Anacardium occidentale Linn), a fim de aplicá-los como aditivos em embalagens de PBAT com propriedades ativas antioxidantes e antimicrobianas. Os extratos foram obtidos pela técnica de extração Sohxlet em três diferentes tempos, 4, 6 e 8 horas, cujo melhor rendimento ocorreu nos tempos de 6 horas para jurema preta e 4 horas para cajueiro. No teste de presença de flavonóides o extrato de jurema preta apresentou maior concentração e no teste de fenólicos totais, utilizando o método de Folin-Ciocalteau, o cajueiro obteve maior concentração. Ambos os extratos apresentaram capacidades antioxidantes significativas pelos dois métodos, fosfomolibdênio e DPPH. cajueiro apresentou melhor halo de inibição frente ao Staphylococcus aureus, e, por isso, foi determinada a sua concentração mínima inibitória (CMI), 0,0170 g.mL-1. Esse extrato foi incorporado ao PBAT, para o ensaio de migração no meio etanólico, por meio do qual foi determinado um modelo cinético e foi observado que a taxa de migração, 0,0167 ?g.mL-1.min-1, foi reduzida em cerca de um dia, indicando bom potencial do extrato para esses tipos de embalagem.

ABSTRACT Packaging has the basic function of protecting the food and ensuring its commercial integrity. They can be produced from biodegradable materials with specific functionalities such as antimicrobial and antioxidant action. In addition, research has been carried out to replace synthetic additives with natural additives, such as plant extracts, due to the chemical compounds present in their mixtures. Poly (butylene adipate co-terephthalate) - (PBAT) has been extensively studied as a possible replacement for conventional polymers due to its biodegradability. Thus, the objective of this work was to evaluate the potentialities of jurema preta (Mimosa tenuiflora) and cajueiro (Anacardium occidentale Linn) plant extracts in order to apply them as additives in PBAT packages with antioxidant and antimicrobial active properties. The extracts were obtained by the Sohxlet extraction technique at three different times, 4, 6 and 8 hours, with the best yield at 6 hours for jurema preta and 4 hours for cajueiro. In the flavonoid presence test the jurema preta extract presented higher concentration and in the total phenolics test, using the Folin-Ciocalteau method, the cashew tree obtained the highest concentration. Both extracts showed significant antioxidant capacities by the two methods, phosphomolybdenum and DPPH. Cashew tree presented better inhibition halo against Staphylococcus aureus, and therefore its minimum inhibitory concentration (MIC) was determined, 0.0170 g.mL-1. This extract was incorporated into the PBAT for the ethanolic migration test, by means of which a kinetic model was determined and it was observed that the migration rate, 0.0167 ?g.mL-1.min-1, was reduced by about a day, indicating good extract potential for these types of packaging.

ABSTRACT: It remains unclear whether temperature and precipitation exert independent control on tropical vegetation and soil C pools. Likewise, it is unknown whether the feedbacks of tropical C pools to climate constraints vary with nutrient availability. These aspects are critical to improving our ability to predict the response of tropical C pools to climate dynamics. This review aimed to assess climate data and the spatial distribution of vegetation and soil C pools across the Brazilian territory to investigate i) whether mean annual precipitation (MAP) and temperature (MAT) exert independent effects on tropical C pools; ii) whether vegetation and soil C pools exhibit hierarchical feedbacks to climate; and iii) how these feedbacks reflect soil nutrient availability. To account for MAP and MAT effects on tropical C cycling, we calculated Ecosystem Effective Moisture (EEM), i.e., the difference between MAP and potential evapotranspiration. We gathered substantial evidence suggesting that under high MAT and MAP controlling EEM, plants exchange more C for water and resorb more nutrients (especially P), which limitations in plant litter reduce microbial-derived C inputs into soil organic matter. Frequent soil saturation under high EEM favors denitrification rates (“open” N cycle), allowing continuous mineralization of litter and shallow soil C pools to release nutrients, sustaining high plant C pools. With decreasing MAP levels, ecosystem C pools depend on MAT controlling evapotranspiration and EEM. Accordingly, decreasing MAP under high MAT reduces EEM, with vegetation and soil C pools co-limited by low net primary productivity (NPP), frequent fire and/or nutrient losses. Otherwise, decreasing MAP and coupled to cool temperatures allow EEM to remain positive, forcing plants to increase deep-rooting and/or shed their leaves, which nutrients are immobilized with microbial-derived C into mineral-organic associations, favoring high soil C pools. Combined, the evidence gathered suggests that the sensitivity of tropical ecosystems to global increases in temperature should not be overlooked, especially if coupled to reductions in precipitation. Overall, the horizontal distribution of vegetation and soil C pools is best described by EEM rather than temperature or precipitation alone, whereas the vertical partition of C in plant-soil systems reflects biotic responses to climate-nutrient constraints.

Abstract The aim of this investigation was to assess the effects of gamma radiation on nanocomposite films (NC films) formed by PCL (polycaprolactone) with MCM-48 nanoparticles (PCL/MCM-48) and PCL with MCM-48 NPs modified with (3-aminopropyl)triethoxysilane (APTES) (PCL/MCM-48-NH2). The nanocomposite films were obtained using the solvent casting method. After preparing the films, they were irradiated at 25 kGy in the presence of air and analyzed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM), transmission electronic microscopy (TEM), as well as for their mechanical properties. The exposure of NC films to gamma radiation at 25 kGy did not cause major changes in either thermal or mechanical properties such as tensile strength and modulus of elasticity. The results revealed that gamma radiation was a successful choice for the sterilization of these materials.

Abstract In this work were developed and evaluated new antimicrobial films of polyhydroxybutyrate (PHB) additivated with polyethyleneglycol (PEG) and clove essential oil (CEO). The PHB/PEG/CEO films were prepared using the solution casting technique. The CEO concentrations varied between 0.0 and 15% (w/w), related to the total mass (1.4 g), without considering the solvent used. The CG-MS analysis showed that the major component of the CEO was eugenol (72.96%). The antimicrobial activity from the CEO was evaluated against three bacteria (E. coli, E. aerogenes and S. aureus). The migration of CEO in the films occurred with all tested simulants. Thermal analysis has shown that the addition of 15% w/w of the CEO causes the biggest changes in the chemical structure of the material, resulting in less energy during film processing. The mechanical data demonstrated that the addition of 15% w/w of the CEO results in more flexible films.

Resumo: Este artigo aborda o anticlericalismo da segunda metade do século XIX em alguns Estados europeus e no Parlamento imperial brasileiro. O momento dinamizador da militância anticlerical foi durante e após o pontificado de Pio IX (1846-1878), período em que a Igreja Católica assumiu uma série de posições e posturas conservadoras frente a transformações políticas, sociais e culturais, colocando-se em rota de colisão com ideias tidas como modernizadoras à época. O ponto de referência, como critério para analisar os casos europeus, foram os discursos e debates ocorridos na Câmara dos Deputados e no Senado Imperial brasileiro. O objetivo da investigação consistiu em evidenciar como parlamentares das duas casas legislativas estavam em sintonia com os movimentos anticlericais na Europa, assim como com o exemplo norte-americano de separação entre Estado e Igreja. Os resultados da pesquisa, cuja principal contribuição foi apresentar a circularidade de ideias e de modelos de separabilidade entre Igreja e Estado, sugerem que a laicidade brasileira, implantada com o advento da República (1889), tem uma dupla fonte, tanto europeia como estadunidense.

Abstract: This article deals with the anticlericalism of the second half of the 19th century in some European States and in the Imperial Brazilian Parliament. The dynamic moment of anticlerical militancy was during and after the Pontificate of Pius IX (1846-1878), a period in which the Catholic Church assumed a series of conservative positions and postures in the face of political, social and cultural transformations that put it on a collision course with as modernized ideas of the time. The reference point, as a criterion for the analysis of European cases, were the speeches and debates that took place in the Chamber of Deputies and in the Imperial Brazilian Senate. The objective of the investigation was to show how the parliamentarians, from the two legislative houses, were in tune with the anticlerical movements in Europe, as well as in the North American example of selection between the State and the Church. The results of the research, the main contribution being the presentation of the circularity of ideas and models of separation between Church and State, suggested the Brazilian secularism, implanted with the advance of the Republic (1889), has a double source, both in Europe in the USA.

RESUMO A celulose, polissacarídeo de origem vegetal, é um biopolímero abundante encontrado na natureza e, portanto, de grande valia para a ciência dos materiais em aplicações na área médica, cosmética, refinaria e outros. Como alternativa à produção tradicional de celulose, tem-se a via microbiana, que resulta numa fibra de caráter nanométrico e com boas propriedades mecânicas. Dentre os diversos micro-organismos que produzem celulose bacteriana (CB), e que apresenta resultados satisfatórios destaca-se a bactéria estritamente aeróbica e Gram-negativa conhecida como Gluconacetobacter hansenii (ATCC - 23769). Esse biopolímero apresenta enorme potencial de aplicação devido às suas propriedades térmicas, mecânicas e biocompatibilidade. Muitas pesquisas estão sendo realizadas para otimizar os processos produtivos de CB, resultando em maiores conversões com um menor custo produtivo. O presente trabalho teve como objetivo, produzir as membranas de celulose bacteriana em meio de manitol (C-MM) ou Hestrin e Schramm (C-MH), e também caracterizá-las por meio de análises de espectroscopia de infravermelho (IV), termogravimétrica (TGA), e difração de raios X (DRX). Como principais resultados, as celuloses produzidas apresentaram imagens morfológicas similares, mas no meio de manitol apresentou maior rendimento (2,09 g.L-1) na produção de CB, quando comparado ao Meio Hestrin e Schramm (HS) (1,15 g.L-1). Além disso, a celulose bacteriana produzida no meio de manitol apresentou maior cristalinidade (78%) que a produzida no meio de Hestrin e Schramm (HS) (65%). Através da análise de IV, foi possível confirmar os grupos funcionais existentes na celulose bacteriana sem a presença de quaisquer contaminantes oriundo do processo de produção. Já com relação a análise termogravimétrica, o polímero formado a partir do meio de manitol apresentou maior estabilidade térmica. Desta forma, os biofilmes produzidos nos diferentes meios apresentaram propriedades diferentes, revelando que as características poliméricas são modificadas em função do meio de crescimento bacteriano.

ABSTRACT The cellulose, polysaccharide of vegetable origin, is an abundant biopolymer found in nature and, therefore, a valuable tool for the science of materials applications in the medical, cosmetic, refinery, and other areas. As an alternative to traditional cellulose production, we have the microbial path, which results in a nanometric fiber with good mechanical properties. Among the several microorganisms that produce bacterial cellulose (BC), the one that presents very satisfactory results is the strictly aerobic and Gram-negative bacteria known as Gluconacetobacter hansenii (ATCC - 23769). This biopolymer presents enormous application potential due to its thermal, mechanical and biocompatibility properties. Many researches are being developed to optimize the productive processes of BC, resulting in greater conversions with a lower production cost. This work aimed to produce the cellulose membranes obtained in mannitol (C-MM) or Hestrin and Schramm (HS) (C-MH) medium and to characterize them through infrared spectroscopy (IR), thermogravimetric (TGA) and X-ray diffraction (XRD) analyses. The celluloses produced presented similar morphological images, but the mannitol medium had a higher yield (2.09 g. L-1) in the BC production when compared to the Hestrin and Schramm medium (HS) (1.15 g. L-1). In addition, the bacterial cellulose produced in medium containing mannitol presented higher crystallinity (78%) than that produced in Hestrin e Schramm (HS) (65%). Through the IR analysis, it was possible to confirm the functional groups present in the bacterial cellulose without any contaminants from the production process. Regarding the thermogravimetric analysis, the polymer formed from the mannitol medium presented higher thermal stability. Finally, the biofilms produced in the different medium had different properties, revealing that the polymeric characteristics change according to the bacterial growth medium.

Resumo Este estudo objetivou determinar a soroprevalência, fatores associados com a soropositividade da infecção por Leishmania em cães e análise espacial em seis municípios do semiárido de Pernambuco. Amostras de sangue foram coletadas de 462 cães, 77 em cada município, e utilizadas para análise sorológica [teste rápido imunocromatográfico (DPP®) e ensaio de imunoabsorção enzimática (ELISA)]. Os sinais clínicos dos cães foram avaliados, e os fatores associados à infecção por Leishmania foram analisados, usando-se modelo robusto de regressão de Poisson. Foi detectada uma soroprevalência de 42,8% (198/462, IC: 95% = 38,6%-47,6%) em cães com resultados positivos em ambos os testes, variando de 29,8% a 55,8%, com maior prevalência no município de Cabrobó (55,8%; P = 0,006). Cerca de 67% (132/198) dos cães apresentaram um ou mais sinais clínicos sugestivos de CanL, como linfadenomegalia, lesões de pele e conjuntivite, os quais foram associados à soropositividade. Altos níveis de soroprevalência foram identificados nas áreas urbanas e rurais de todos os municípios, e os buffers da área de vôo do flebotomíneo em torno dos casos cobriam quase todas as áreas dos municípios. A análise espacial revelou um cluster significativo, mostrando um risco relativo de 1,88 na área urbana de Cabrobó. A maior densidade de casos em áreas urbanas indica a necessidade de medidas efetivas de controle contra o CanL, para evitar o surgimento da doença canina e humana.

Abstract This study aimed to determine the seroprevalence, factors associated with seropositivity to Leishmania infection in dogs and spatial analysis in six municipalities in the semiarid region of Pernambuco, Brazil. Blood samples were collected from 462 dogs, 77 in each municipality, and used for serological analysis [dual path platform (DPP®) and enzyme-linked immunosorbent assay (ELISA)]. Clinical signs of dogs were evaluated and associated factors for Leishmania infection were analyzed using robust Poisson regression model. A seroprevalence of 42.8% (198/462, IC: 95% = 38.6%-47.6%) was detected in dogs that tested positive in both tests, ranging from 29.8% to 55.8%, with higher prevalence in the municipality of Cabrobó (55.8%; P = 0.006). About 67% (132/198) of the seropositive dogs showed one or more clinical signs suggestive of canine leishmaniasis (CanL), such as lymphadenomegaly, skin lesions and conjunctivitis, which were associated with seropositivity. High seroprevalence levels were identified in urban and rural areas in all the municipalities, and the buffer for sand flies around cases covered almost these entire areas. Spatial analysis revealed a significant cluster, showing a relative risk of 1.88 in the urban area of Cabrobó. The higher density of seropositive dogs in urban areas indicates the need effective control measures against CanL to prevent the emergence of canine and human diseases.

ABSTRACT This study aimed: i) to evaluate the influence of fertilization and irrigation management on eucalyptus plantations for soil carbon (C) dynamics; ii) to evaluate the impact of fertilization and irrigation management on eucalyptus plantations in the C allocation in depth compared to the Cerrado biome. This study was carried out in an eucalyptus plantation at the end of the third rotation (7 years), which received different fertilizations and irrigations, and a Cerrado area was used as reference. Soil samples were collected in trenches and the gases (CO2 and CH4) on the surface. The total organic carbon (TOC) is more influenced by the availability of water than nutrients. Soils under eucalyptus stands are more efficient at C stocks in depth than the Cerrado and act as a liquid drain of CO2 and CH4 from the atmosphere.

ABSTRACT Forest cover in areas degraded by mining is an alternative way of mitigating CO2 concentrations in the atmosphere by fixing C in tree biomass. This study evaluated the growth and C stocks of forest cover in an area of bauxite mining with four sources of fertilizer. Height (Ht), diameter at ground level (DGL), and diameter at breast height (DBH) were determined in Anadenanthera peregrina (Ap), clonal Eucalyptus (Euc), and a mixed plantation of 16 native forest species (Nat) at 6, 18, 36, and 56 months of age. Trunk+bark volume, biomass, and C stock were also determined for these forest covers at 56 months of age. The fertilization treatments were a standard (SF) adopted by the company, SF plus organic fertilizer (OF), chemical fertilizer (CF), and OF+CF. Euc displayed greater values of Ht, DGL, and DBH under OF+CF and OF. Fertilization did not influence the Ht and DBH of Ap, but DGL was higher under OF+CF at 36 months compared to SF. The Ht values of Nat were influenced by fertilization at 18 months, with the lowest values under SF. The fertilization influenced the DGL of Nat at 36 and 56 months, which did not occur with DBH. The pioneer species had higher Ht, DGL, and DGB compared to non-pioneer species, regardless of the type of fertilization studied. Fertilization influenced the Ht and DGL of pioneer species at 18 and 36 months of age and only the Ht of non-pioneer species. The estimates of Euc biomass (255 Mg ha-1) and C stocks (120 Mg ha-1) under OF+OC were four times greater than in Ap and Nat, which showed no difference between themselves or the types of fertilization. The growth and estimates of volume, biomass, and C stocks of the forest cover were comparable to those of unmined areas. Euc had the greatest growth, biomass, and C stocks.

ABSTRACT Harvesting and reform in eucalyptus can lead to changes in soil organic matter (SOM). The objective of this work was to evaluate the changes in total organic C (TOC) and N (NT), C and N in humic acid (HA), fulvic acid (FH), light organic matter (LOM) and microbial biomass (MB), in Ultisol of eucalypt stands over one, two and four years of renovated areas in Rio Grande do Sul state. After the first year of eucalyptus reform, there were 78% of increases in TOC (0.0-1.0-m soil layer). After two years, there was an increase in TN and an average reduction of 52% in LOM-C (0.0-0.1-m soil layer). FA-C, HA-C, and HU-C presented mean reductions of 43 Mg ha–1 (0.0-1.0-m soil layer) after four years of reform. The litter contribution of previous crop and the crop residues from the harvest resulted in increments of the SOM fractions. However, there is a negative effect in later years.