Navegando por Orientadores "VASCONCELOS, Steel Silva"

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Acesso aberto (Open Access)
Benefícios ambientais e econômicos de sistemas agroflorestais de Tomé-Açu, Pará
(Universidade Federal do Pará, 2023-04-22) SUZUKI, Patrícia Mie; VASCONCELOS, Steel Silva; http://lattes.cnpq.br/0719395243841543; https://orcid.org/0000-0003-2364-8822
The global demand for food and the advance of climate change generate pressure for sustainable production systems that generate multiple benefits. Agroforestry systems (AFS) are productive models with the potential to meet the demands of society and the environment. In this sense, this research aimed to evaluate agroforestry systems' contribution to climate change mitigation, biodiversity conservation, and income generation in the municipality of Tomé-Açu, Pará. Twelve areas of multi-stratified AFS were selected and a 30 x 30-meter plot was installed in each system. An agroforestry inventory and an interview with the producer about the socioeconomic profile and environmental perception of the AFSs were carried out. The data were used to evaluate the influence of plant richness and other variables on the benefits of "Mitigation of climate change", "Biodiversity conservation" and "Income generation", through the indicators aboveground biomass carbon stock, Shannon index (H') and gross income, respectively. For this, we used Principal Component Analysis (PCA) to select the variables and linear regression to create the models. All data from the agroforestry inventory and the statistical analyses were performed in the R 4.2.2 computing environment. In general, 83% of the farmers reported being satisfied or very satisfied with the economic return on the AFSs, in addition to citing several environmental services. Richness (S) per system ranged from 3 to 11 species and Shannon diversity index (H') between 0.55 and 1.77. The average carbon stock of the aboveground biomass in the studied AFSs was 45.2 Mg ha-1, with a variation between 27.4 and 63.0 Mg ha-1. The values of carbon stock in the cocoa, cupuaçu, açaí, dendê, and other components were statistically similar, but differed significantly from the carbon stock found in the forest component (gl=2; χ2=71.7; p=1.834e-13). The average value of annual gross income from the sale of these producers was R$13,758, 53/ha and ranged between R$1,687.50 and R$26,250/ha. In the systems with oil palm (AFSs A1, A2 and A3), the palm tree considerably increased the gross income of the AFSs, contributing 58, 48 and 78% of the total income, respectively, despite the low density of individuals, with an average of 69 ind ha-1, in the areas, in comparison with the other main species. In this study, it was not possible to confirm the influence of plant richness on the generation of climate benefits, biodiversity conservation, and income generation. However, other variables influenced the benefits of the analyzed AFSs. "SAF type", "oil palm density" and "shade species density" performed best on carbon stock, Shannon diversity index and gross income, respectively. As for the benefit scores, in general, most of the AFSs showed unevenly distributed scores for each benefit. Therefore, we conclude that plant richness was not the variable that influenced the benefits evaluated, but rather a set of variables analyzed, ratifying the complexity of Tomé-Açu's AFSs. In general, the AFSs of Tomé-Açu meet the expectations of producers in terms of economic return, besides generating benefits related to climate change mitigation and biodiversity conservation. In particular, the AFSs with the oil palm component showed better performance in the scores of benefits generation.
Acesso aberto (Open Access)
Colonização micorrízica arbuscular em floresta secundária na Amazônia sob remoção de serrapilha e irrigação do solo
(Universidade Federal do Pará, 2010) MAIA, Rodrigo da Silva; VASCONCELOS, Steel Silva; http://lattes.cnpq.br/0719395243841543
We evaluate the effect of alteration of availability of substrate (litterfall) and water about the arbuscular mycorrhizal colonization and chemical attribut of soil in Secondary Forest in the eastern Amazon. The percentagem of mycorrhizal colonization (PMC) was analyzed in apogeotropic roots and roots present in the surface 0-10 cm layer of soil, spore density, glomalin production and physico-chemical attributes of soils in four plots of treatment to litter removal, four plots of irrigation treatment and four control plots. The plots measuring 20 m x 20 m. In each plot was collected four single samples of soil and roots divided into four areas. The results showed that litter removal reduced significantly the PMC in roots, but had no effect on spore density. The litter removal decreased availability of nitrogen and organic carbon in soil, but there was no influence of reduced availability of nutrients in the soil for mycorrhizal colonization. The Glomalin which is produced by hyphae of arbuscular mycorrhizae, and is aggregated with soil organic matter was also reduced by litter removal. The irrigation treatment did not affect the PMC, and spore density in soil and did not affect the availability of nutrients. The study allowed to show that changes in land cover can cause serious damage to the plant-fungus symbiosis.
Acesso aberto (Open Access)
Colonização micorrízica e disponibilidade de fósforo no solo em sistemas agroflorestais com palma de óleo na Amazônia.
(Universidade Federal do Pará, 2020-01-20) MAIA, Rodrigo da Silva; VASCONCELOS, Steel Silva; http://lattes.cnpq.br/0719395243841543; https://orcid.org/0000-0003-2364-8822
Phosphorus (P) is considered the most expensive and limiting nutrient for agricultural production in the tropics, due to the limitations of phosphate reserves and adsorption phenomenon. In the Amazon agricultural production may be limited by 90% due to P deficiency. In recent decades the introduction of monocutives, such as oil palm (Elaeis guineensis) in the state of Pará, has caused changes in land use, affecting nutrient availability and environmental dynamics. In this context, the insertion of oil palm into an alternative soil management model and conservationists such as the Agroforestry System (AS), can help reduce dependence on imported P, ensure greater use of P in the soil through organic sources and increase plant uptake through arbuscular mycorrhizae symbiosis. However, there is little information on the contribution of AS to P availability and mycorrhizal colonization in perennial crops like an oil palm in tropical agrosystems, especially in the Amazon. The aim of this study was to evaluate the labile and moderately P (organic and inorganic) fractions in soil and arbuscular mycorrhizal colonization in oil palm planted in biodiverse and monoculture agroforestry systems in the Brazilian Amazon. The P fractions were determined by sequential extraction method described by Hedley and mycorrhizal colonization was evaluated by intersection magnification method. Mycorrhizal colonization was generally 3.5 times higher in oil palm cultivated in Agroforestry in relation to monoculture and Agroforestry did not differ from monoculture in the supply of labile P and have a larger pool of moderately labile P in the soil. The results of the study showed that the adoption of Agroforestry Systems in oil palm cultivation in the Amazon is a promising practice to increase mycorrhizal colonization in this species and represents a type of advantageous management for the supply of available P and for the maintenance of P reserves compared to monoculture.
Acesso aberto (Open Access)
Dinâmica de serapilheira e produção de raízes finas em plantios de Paricá (Schizolobium Parahyba Var. Amazonicum) e floresta sucessional em Aurora do Pará, Amazônia Oriental
(Universidade Federal do Pará, 2009-06-29) SILVA, Antonio Kledson Leal; VASCONCELOS, Steel Silva; http://lattes.cnpq.br/0719395243841543
The establishment of silviculturals and agroforestry systems with the paricá (Schizolobium parahyba var. amazonicum) expanded in the state of Pará, brazil, usually as alternative to reforestation of degraded areas (abandoned pasture). However lacking basic studies on the cycling of organic matter to understand the potencial of paricá to recover degrades areas. Set up an experiment on the farm Tramontina, Aurora do Pará, to evaluate process connected with cycling of organic matter, how the litter production (litterfall), litter stock, production of fine root during 12 months (October 2007 and September 2008), in treatments with plantations of paricá with five years, in the following arrangement: paricá single (PS), consortium paricá + freijó (Cordia goeldiana) (PF), Agroforestry systems with paricá, freijó and curauá (Ananas comusus var. erectifolius) (PFC). This treatments with paricá was compared with an area of reference (successional forest ecosystem with 25 years of age) (SUC). The treatments of paricá presented annual litter production under SUC (8,79 ± 0,08 Mg ha-1 yr-1), no significant difference between treatments PS (6,05 ± 0,15 Mg ha-1), PF (6,08 ± 0,13 Mg ha-1 yr-1) and PFC (6,63 ± 0,13 Mg ha-1 yr-1). The monthly production of litter was significativety major in dry season than wet season. The largest stock of litter has been identified in treatments with paricá PS (7,7 ± 1,0 Mg ha-1) and PF (7.4 ± 0,1 Mg ha-1), while the SUC presented an stock of 5.9 ± 1,3 Mg ha-1. This results is related to the lower rate of decomposition found in treatments with paricá. The production of total fine roots (live + dead) was significativelly major in the treatments PS (380,3 ± 20,6 g m-²), PF (343,0 ± 18,4 g m-²) and PFC (265,5 ± 9,9 g m-²) than SUC (107,2 ± 2,7 g m-²), the variation of fine roots production in the period of study is associate with a seasonality of pluviometric precipitation; the fine roots production decreases during the period of increased precipitation and increases with the arrival of the dry period. Treatments with paricá showed good ability to provide organic material above and below the ground. More specifically, the paricá presented high production and storage of litter on soil, which are desirable attributes in systems for recovery of degraded areas.
Acesso aberto (Open Access)
Efluxo de CO2 do solo em sistemas de produção de palma de óleo na Amazônia Oriental
(Universidade Federal do Pará, 2017-02-21) COSTA, Alessa Nayhara Mendanha; VASCONCELOS, Steel Silva; http://lattes.cnpq.br/0719395243841543
Tropical forest areas play an important role in the global carbon cycle. However, anthropogenic disturbances have altered the structure of the ecosystem and consequently imply in the carbon budget. To evaluate how changes in land use influence the efflux of CO2 from the soil (the main pathway of CO2 displacement in soil to atmosphere), it is possible to understand how the different types of vegetation affect the CO2 efflux of the soil, evaluating the variables that contribute to this process. A greater understanding of this influence motivates the study in different ecosystems, which seek to identify and develop practices that increase carbon stock and nutrient cycling, such as agroforestry systems (SAFs). Due to the expressive expansion of the oil palm in the Amazon region, the objective of this research was to evaluate the effects of CO2 efflux from the soil, as well as its control variables, in two oil palm production systems (conventional palm oil production systems and agroforestry systems with oil palm). The research was developed in the municipality of Tomé-Açu in areas of family farming and production. Soil CO2 efflux, soil temperature and soil gravimetric moisture were evaluated between March 2016 and November 2016. The stocks of fine roots and litter in the systems were evaluated in the period of higher precipitation (May) and lower precipitation (October). Soil CO2 efflux was higher in successional forest areas, intermediate in oil palm agroforestry systems, and lower in conventional palm oil systems. The CO2 efflux of the soil is sensitive to the "conversion" of forest areas into oil palm crops. The "soil metabolism" in the more diversified oil palm (SAF) system is more similar to that of the more ecologically integrated system (secondary forest).
Acesso aberto (Open Access)
Efluxo de dióxido de carbono do solo na transição floresta-sistema agroflorestal no município de Tomé Açu, Pará
(Universidade Federal do Pará, 2015-08-31) PINHEIRO, Larissa Paulina Souza; VASCONCELOS, Steel Silva; http://lattes.cnpq.br/0719395243841543
The soil carbon dioxide (CO2) efflux corresponds to the principal flow of carbon from the biosphere to the atmosphere. Tropical soils, which usually show high moisture and temperature, offer very favorable conditions for the production of CO2 resulting from, the decomposition of organic matter, root respiration and microbial respiration, increasing soil CO2 emission to the atmosphere. Soil management practices influence the controlling factors of the soil carbon stock and CO2 emission. A greater understanding of this influence has stimulated studies on all ecosystems, which, among other things, seek to identify and/or develop practices that increase carbon storage and reduce the emission of soil CO2, as is the case of agroforestry. Due to the large global scientific interest in understanding the physical and biological processes involving CO2 fluxes between the surface and the atmosphere, the aim of this research was to evaluate the effects of the transition from secondary forest to oil palm-based agroforestry systems on the soil CO2 efflux and soil biotic and abiotic factors. The experiment was conducted in the municipality of Tomé Açu, northeast Pará, in a project which has been investigating models of palm oil production systems in agrosilvicultural arrangements in the context of smallholder agriculture. The soil CO2 efflux was measured with a portable photosynthesis measurement system (LI-6400) coupled to a soil respiration chamber. We also measured soil gravimetric moisture and temperature, soil respiration (SR), microbial biomass carbon (MBC), soil organic carbon, fine roots stock and litter stock in two AFS and a remaining secondary forest. Measurements of CO2 efflux and soil and plant sampling were taken between January and April 2015 and were carried out fortnightly. The soil CO2 efflux was mainly influenced by soil temperature and moisture in both agroforestry systems. The forest-AFS transition significantly affected the soil CO2 efflux, fine roots, MBC and SR. The transition from secondary forest to AFS with oil palm and the spatial variability of the species or arrangement of the systems affected the soil quality. These changes may be linked to impacts of changes in the structure and species composition of the systems and the management of soil organic matter.
Acesso aberto (Open Access)
Emissão de dióxido de carbono e estoque de carbono em sistemas convencionais e alternativo de produção agropecuária no Nordeste paraense
(Universidade Federal do Pará, 2011-08-25) LEMOS, Elane Cristina Melo; VASCONCELOS, Steel Silva; http://lattes.cnpq.br/0719395243841543
Use of agricultural conservation practices such as slash-and-mulch, as an alternative to slash-and-burn, is less harmful to biogeochemical cycling and helps to mitigate climate change. The aim of this study was to estimate soil carbon emission and stocks in smallholder agricultural units in Northeast of Pará. The study was carried out in the municipality of Mãe do Rio. Average annual temperature in this area varied from 25 to 28 °C and rainfall typically is higher than 2500 mm; predominant soil is Yellow Dystrophic Oxisol with texture varying from medium to clayey. In this research, we selected three land use systems (Schizolobium amazonicum plantation, Manihot esculenta crop, and silvopastoral), which were compared with a reference area (regrowth forest); we established four 20 m x 20 m plots in each system. We measured monthly soil CO2 efflux as well as soil carbon stock and aboveground litter carbon stock. Analysis of variance was used to test the effects of land use systems and regrowth forest effects on carbon emission and stock; Tukey test at 5% was used to compare treatment means. The silvopastoral system showed the highest monthly soil CO2 emissions, which were observed during the rainy season; this system also had the largest annual emission. Soil carbon stock was significantly higher in the regrowth forest was 157 ± 31,10 Mg ha-1 (0-100 cm). Litter stock was higher for the non-woody fraction than the woody fraction for both land use and regrowth forest systems. The largest stock of carbon in non-woody litter (overall mean = 4.31 ± 3,0 Mg ha-1) was observed in January 2010. Our results suggest that the land use systems that do not use fire in land preparation, such as the slash-andmulch system, helped to maintain carbon biogeochemical cycling.
Acesso aberto (Open Access)
Estoque e ciclagem de carbono de sistemas agroflorestais em Tomé-Açu, Amazônia Oriental
(Universidade Federal do Pará, 2010) BRANCHER, Tobias; VASCONCELOS, Steel Silva; http://lattes.cnpq.br/0719395243841543
Agroforestry systems (SAFs) constitute an important agricultural practice of land use directed at food production and environmental services. The objective of this study was to evaluate carbon stock and cycling of 4 agroforestry systems (SAF) with different age and species composition, and a secondary vegetation (“capoeira”), in Tomé-Acu, northeast of Pará State, Eastern Amazon. Carbon stocks in soil, litter and aboveground biomass were measured. Carbon flux associated with litterfall and aboveground biomass increment was measured over a year between 2008 and 2009. The SAFs were divided into four categories, called SAF 1, SAF 2, SAF 3 and SAF 4, being (SAF 1: cacau, açaí, bananeira e seringueira, 14 years old, SAF 2: cacau, açaí, bananeira, seringueira, taperebá, paricá e macacaúba, 14 years old, SAF 3: cupuaçu, açaí, teca e mogno, 9 years old, SAF 4:cupuaçu, açaí e paricá, 9 anos years old). In each system we set four plots, where soil and plant samples were collected, including diameter at breast height (DAP) and height (h), which were used to estimate the aboveground biomass. Within plots were installed collectors to measure the deposition of litterfall and sampled soil and litter used to estimate carbon stocks. There was no significant difference between SAFs in relation to soil carbon stock. The SAF 3 was significantly lower than the other SAF in relation to aboveground carbon and SAF 4 had the highest annual litterfall deposition among all treatments. The SAF did not differ in relation to soil and litter carbon stocks. Net primary production reached 2.54, 6.11, 9.54 and 16.27 Mg C ha-1 yr-1 in SAF 1, 2, 3 and 4, respectively. The age of the SAFs had no significant effect on the amount of carbon accumulated during one year.
Acesso aberto (Open Access)
Estoques e fluxos de carbono em plantações florestais jovens de Acacia mangium e Schizolobium parahyba var. Amazonicum na Amazônia Oriental
(Universidade Federal do Pará, 2010) FREITAS, Jorge Fernando Barros de; VASCONCELOS, Steel Silva; http://lattes.cnpq.br/0719395243841543
Forest plantations are considered as an alternative land use to mitigate the effects of climate change due to their potential for carbon sequestration in tree species. However, there is little information about carbon stocks and fluxes in forest plantations commonly used in the tropics, especially in the Amazon. The aim of this study was to quantify aboveground carbon stock and soil carbon dioxide (CO2) efflux in Acacia mangium Willd and Schizolobium parahyba var. amazonicum at different spacings. The study was conducted in Dom Eliseu, Pará, whose climate has a mean annual temperature around 25 ºC, annual rainfall varies from 2250 to 2500 mm; predominant soil is A moderate typic dystrophic Oxisol loamy soil. In this study we selected two species (A. mangium and S. parahyba var. Amazonicum) at two spacings (4.0 x 2.0 m and 4.0 x 3.0 m) with two replications, resulting in 4 treatments and 8 plots studied for a period of one year, from 2.5 to 3.5 years old. The plots measured 48 m x 60 m. We measured: height, diameter at breast height, soil CO2 flux, and estimated aboveground carbon stock. Mean soil CO2 efflux in plantations of A. mangium was 5.61 ± 1.30 Mg C ha-1 yr-1, and for S. parahyba the overall average was 7.07 ± 1.50 Mg C ha-1 yr-1. Annual accumulation of carbon in above-ground biomass A. mangium was 16.41 ± 1.16 and 14.03 ± 0.82 Mg C ha-1 yr-1 in 4.0 x 2.0 m and 4.0 x 3.0 m and 3.0 m, respectively. In S. parahyba the annual accumulation rate was 8.93 ± 1.87 Mg C ha-1 yr-1. A. mangium plantations accumulated more carbon in aboveground biomass than S. parahyba, with lower annual soil CO2 efflux smaller in relation to S. parahyba in both spacings. Overall A. mangium plantations in the 4.0 x 2.0 m spacing are recommended for carbon sequestration projects. In relation to S. parahyba, the 4.0 x 3.0 m would be recommended due to the same efficiency in carbon sequestration with lower requirement of inputs (seedlings) compared to 4.0 x 2.0 m. Continuos monitoring of the studied plantations would be very suitable to better understand the carbon dynamics.
Acesso aberto (Open Access)
Fluxo de óxido nitroso (N2O) do solo em um sistema agroflorestal em Tomé Açu, nordeste do Pará
(Universidade Federal do Pará, 2013-08-14) SOUZA, Gisele Nerino Brito de; VASCONCELOS, Steel Silva; http://lattes.cnpq.br/0719395243841543
The study on the emission of nitrous oxide (N2O) from soil in agricultural systems contributes to the understanding of global climate change, which could aid in minimizing negative impacts on the environment. The importance of this gas due to its direct relationship with the global greenhouse effect and to stratospheric ozone depletion. Some agricultural practices performed in agroforestry systems, when managed correctly can help curb these negative impacts. The use of legumes in these systems has become increasingly common, but its relationship with N2O emissions is still not well understood. Given the importance of processes and factors contributing to the increase in N2O emissions, this study aimed to examine the contribution of legume species (Inga edulis Mart.) And non-legume (Theobroma cacao) in nitrous oxide emissions from soil to the atmosphere through the use of static cameras and different climatic characteristics in an agroforestry system in the city of Tome Açu northeastern state of Para the experiment was conducted in an area of agroforestry (SAF) located in Tome Acu ( PA ) ( 02 ° 33'38 , 5 " S , 48 ° 21'36 , 1 " W ) within the February/2013 August/2012, totaling 11 field campaigns, a fortnightly basis. Static chambers of circular type (diameter = 300 mm ) and rectangular ( 37.5 cm x 57 cm ) were used to determine the emission of N2O from the soil, with the aid of polypropylene syringes with a volume of 20 ml and transferred to flasks borosilicate. The N2O concentration was determined by gas chromatography using a gas chromatograph Varian CP 3800 gas model with an electron capture detector. The variation of N2O emissions were 2.74 to 42.54 mg N m-2 h-1 pulses to and from 1.65 to 30.46 mg N m-2 h- 1 for non-legumes. Higher emissions were observed in the wet season compared to the dry season. The gravimetric soil moisture, soil temperature and inventory of plant residues on the soil were the factors that most N2O emissions from the soil.
Acesso aberto (Open Access)
Indicadores de carbono do solo em sistemas agroflorestais com potencial de uso em processo de transição produtiva agroecológica
(Universidade Federal do Pará, 2017-04-18) PANTOJA, Kelly Regina da Silva; VASCONCELOS, Steel Silva; http://lattes.cnpq.br/0719395243841543
Traditional production systems have proved to be unsustainable in the socioeconomic and environmental spheres. A less aggressive agriculture is an alternative for the conservation of ecosystems. The process of changing from a traditional management for an alternative one is called a productive transition. The objective of this study was to evaluate soil carbon indicators in traditional and alternative production systems in areas of agroecological productive transition. The study was conducted in family farms located in Igarapé-Açu and Tomé-Açu, municipalities of the northeast of Pará. Traditional (slash-and-burn) and alternative (cut-and-grind and AFS) systems were selected, as well as secondary and primary forests (used as a reference area). The litter stocks, carbon stocks in the soil, densimetric fraction of soil organic matter and litter were analyzed. Also, an evaluation of the potential of the carbon stock as a subsidy to estimate environmental services was made. The cut-and-grind system presented the highest litter stock and carbon stock in the litter, while the AFS did not differ from reference areas. For the carbon stock in the soil and the densimetric fraction of soil organic matter no significant differences were found between the systems and the reference areas. Alternative systems had a large capacity to store carbon. The quantification of carbon stocks (soil and litter) and the stock of litter shows potential as an indicator to subsidize the provision of environmental services, as well as certify the quality of agroecosystems.
Acesso aberto (Open Access)
O papel de espécies arbóreas e fatores edáficos na variação espacial do sistema serapilheira em uma floresta de terra firme na Amazônia: conhecimento e perspectivas para a conservação
(Universidade Federal do Pará, 2020-11-13) QUEIROZ, Maria Elisa Ferreira de; LAVELLE, Patrick; http://lattes.cnpq.br/5850683517396587; VASCONCELOS, Steel Silva; http://lattes.cnpq.br/0719395243841543; https://orcid.org/0000-0003-2364-8822
The dense ombrophilous forest, also known as tropical rain forest, is a formation that presents great complexity in the composition, distribution and density of species and occupies a good part of the Brazilian Amazon. In the region, the differences between plant communities and animals form a mosaic divided into eight areas or centers of endemism, separated by the main rivers, with their own biota and evolutionary relationships, three of which (Belém, Xingu and Tapajós) are entirely Brazilian. The Belém endemism center is the most threatened by deforestation and small-scale local investigations are essential to understand the effects of this disturbance on the functioning of the forest. The decomposition of litter is one of the key factors of this functioning and occurs in a hierarchical sequence of interaction processes mediated by climatic factors (temperature and humidity), physical properties of the soil, chemical limitations related to the sources of resources and biological regulation (micro and macroorganisms). In this research, it was discovered that sensitive changes in the structure of a primary forest threatened by urban growth, caused by the intensity of the natural succession dynamics, altered the humus system, since the organisms' competition for nutrients depleted the soil during the regeneration of areas affected by falling trees. Thus, the physical-chemical conditions of the forest soil became a selective filter of tree species and the major factors in the decomposition hierarchy, since temperature and humidity had little variation in the system. Then, leaves of specific tree species of the humus system, which formed a finer structure, determined the diversity of saprotrophic fungi positively related to the better quality of these leaves and the soil. Conversely, where the litter morphology was thicker and more structured, there was an increase in the diversity of litter transforming macrofauna, to the detriment of earthworm populations, which preferred higher quality leaves and soil. Soilplant-decomposer interactions are indicators of decomposition speed in humus systems, with consequent formation of mosaics of litter spots with different decomposition dynamics. Thus, places where humus function was classified as Mesomull or Oligomull were characterized by soils with a high available carbon content and good cation exchange capacity. Mull type humus systems are sensitive to variations in soil quality and earthworm activity. This explained the change to the Dysmull humus system in areas with large leaves, characterized by low nutrient availability, as confirmed in the soils of these places, although a slow functioning may indicate a conservative state of organic matter. The methodology proved to be favorable to predict changes at different scales that may affect the forest restoration.
Acesso aberto (Open Access)
O papel de espécies arbóreas e fatores edáficos na variação espacial do sistema serapilheira em uma floresta de terra firme na Amazônia: conhecimento e perspectivas para a conservação
(Universidade Federal do Pará, 2020-11-13) QUEIROZ, Maria Elisa Ferreira de; LAVELLE, Patrick; http://lattes.cnpq.br/5850683517396587; VASCONCELOS, Steel Silva; http://lattes.cnpq.br/0719395243841543; https://orcid.org/0000-0003-2364-8822
The dense ombrophilous forest, also known as tropical rain forest, is a formation that presents great complexity in the composition, distribution and density of species and occupies a good part of the Brazilian Amazon. In the region, the differences between plant communities and animals form a mosaic divided into eight areas or centers of endemism, separated by the main rivers, with their own biota and evolutionary relationships, three of which (Belém, Xingu and Tapajós) are entirely Brazilian. The Belém endemism center is the most threatened by deforestation and small-scale local investigations are essential to understand the effects of this disturbance on the functioning of the forest. The decomposition of litter is one of the key factors of this functioning and occurs in a hierarchical sequence of interaction processes mediated by climatic factors (temperature and humidity), physical properties of the soil, chemical limitations related to the sources of resources and biological regulation (micro and macroorganisms). In this research, it was discovered that sensitive changes in the structure of a primary forest threatened by urban growth, caused by the intensity of the natural succession dynamics, altered the humus system, since the organisms' competition for nutrients depleted the soil during the regeneration of areas affected by falling trees. Thus, the physical-chemical conditions of the forest soil became a selective filter of tree species and the major factors in the decomposition hierarchy, since temperature and humidity had little variation in the system. Then, leaves of specific tree species of the humus system, which formed a finer structure, determined the diversity of saprotrophic fungi positively related to the better quality of these leaves and the soil. Conversely, where the litter morphology was thicker and more structured, there was an increase in the diversity of litter transforming macrofauna, to the detriment of earthworm populations, which preferred higher quality leaves and soil. Soilplant-decomposer interactions are indicators of decomposition speed in humus systems, with consequent formation of mosaics of litter spots with different decomposition dynamics. Thus, places where humus function was classified as Mesomull or Oligomull were characterized by soils with a high available carbon content and good cation exchange capacity. Mull type humus systems are sensitive to variations in soil quality and earthworm activity. This explained the change to the Dysmull humus system in areas with large leaves, characterized by low nutrient availability, as confirmed in the soils of these places, although a slow functioning may indicate a conservative state of organic matter. The methodology proved to be favorable to predict changes at different scales that may affect the forest restoration.
Acesso aberto (Open Access)
Serviços ecossistêmicos por sistemas agroflorestais na Amazônia: uma análise bibliométrica
(Universidade Federal do Pará, 2022-06-28) CONCEIÇÃO, Thayná Karina da Silva; VASCONCELOS, Steel Silva; http://lattes.cnpq.br/0719395243841543; https://orcid.org/0000-0003-2364-8822
Over the last few decades, ecological concepts and evolutionary biological theory have influenced proposals in the environmental movement. In this context, AFS agroforestry systems gain notoriety as an agroecological alternative, due to their socioeconomic benefits and the generation of ecosystem services. Following this reasoning, the objective of this study was to measure in qualitative values the contribution of SAFs to the nature of these services with a focus on sustainability, and on other benefits, also aligned with the broader socioeconomic context of the Sustainable Development Goals (SDGs), of the 2030 agenda of the United Nations Organizations (UN). The studies aimed to qualitatively analyze aspects in which the SAFs were inserted. From the bibliographical survey with the use of research terms in the Web of Science database, then the curation of these data was carried out, presenting bibliometric metrics, such as maps, graphs and tables. With a total of 409 publications, and taking into account region and topic criteria, we reached a reduced number of articles of 134. These results show that interest in research in the agroforestry field has improved, but in a gradual and heterogeneous way. The most frequent ecosystem services were Support and Provision. This study can increase opportunities for future research, and suggest a qualitative analysis of the benefits of AFS that can contribute to generating ecosystem services in the Brazilian Amazon.
Acesso aberto (Open Access)
Variação temporal do efluxo de dióxido de carbono CO² do solo em sistemas agroflorestais com palma de óleo (Elaeis guineensis) na Amazônia Oriental
(Universidade Federal do Pará, 2013-09-20) SILVA, Carolina Melo da; VASCONCELOS, Steel Silva; http://lattes.cnpq.br/0719395243841543
The Amazon region has been subjected to continuous deforestation and expansion of land use for the implementation of activities such as cattle ranching, logging, agriculture, mining and urbanization. The burning and decomposition of forest biomass releases gases that contribute to global warming, such as carbon dioxide (CO2). In this context, there is interest in assessing the dynamics of soil CO2 efflux in the Amazon, especially in oil palm (Elaeis guineensis) agroforestry systems, due to the current large expansion of this crop in the state of Pará, which has become one of the largest producers of the country. This study aimed to investigate the dynamics of soil CO2 efflux in palm oil cultivation in agroforestry systems in the Amazon considering temporal and biotic and abiotic factors that directly influence this process. We quantified biotic factors: microbial biomass, total soil carbon, soil basal respiration, fine root and soil zone of influence of planted species, and abiotic factors: moisture and soil temperature, in two oil palm-based agroforestry systems (adubadeiras and biodiverso systems), during the dry and rainy periods. The results showed that the highest soil CO2 efflux occurred during the rainy season, probably due to increased microbial activity during this period influenced by climatic factors coupled with biotic factors. The biodiverso system showed higher soil efflux than the fertilizer adubadeiras system, probably due to increase biological activity in former system. The soil CO2 efflux showed no strong correlation with the tested variables. It was concluded that the soil CO2 efflux was influenced by rainfall seasonality only. The fact that the systems were be too young (~3 yr-old) may represent the main factor for a lack of stronger relationship of soil CO2 efflux and the variables analyzed.