Navegando por Assunto "Liteira"

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Acesso aberto (Open Access)
Biogeoquímica comparativa de ecossistemas de floresta sucessional e Virola surinamensis na região dos tabuleiros costeiros do estuário guajarino, Amazônia oriental, Brasil
(Universidade Federal do Pará, 2005-04-14) OLIVEIRA, Francisco de Assis; RAMOS, José Francisco da Fonseca; http://lattes.cnpq.br/8189651755374537
Studies of comparative biogeochemistry of Virola surinamensis (VSU) and successional forest ecosystems (FSU) in the coastal tableland region of eastern Amazonia were carried out to studies on i) factors that cause differences in fluxes and stocks of organic matter and chemical elements, such as potassium (K), calcium (Ca), magnesium (Mg), manganese (Mn), iron (Fe), copper (Cu) and zinc (Zn) within the biogeochemical matrix of litterfall, the forest floor and pedochemical matrix stocks, and ii) factors that control the variation in soil carbon dioxide (CO2) flux within the VSU and FSU ecosystems. The major flux of the biogeochemical matrix (organic matter) from the trees to the forest floor was higher (p < 0,001) in the successional forest ecosystem (FSU) than in the Virola surinamensis ecosystem (VSU). This was due to higher floristic diversity in the FSU, as well as the elevatedlevel of ecosystem manipulation in the VSU, where the burning of phytomass released K, Ca, Mg, Mn, Fe, Cu and Zn oxides, causing in situ enrichment of the soil bases. The K, Mn and Zn fluxes were significantly higher (p < 0,001) in the FSU, although Fe flux was higher (p < 0,001) in the VSU. These results show the effect of high floristic diversity of the biogeochemical matrix in the successional ecosystem, while in the Virola surinamensis ecosystem, results indicate the possibility of biogenic Fe accumulation as a genotypic character of Virola tree species. The Mg, Ca and Cu fluxes were similar (p <.0,05) between ecosystems, as demonstrated by the semivariogram nugget effect. This indicated the absence of spatial influence on the processes controlled by the biogeochemical matrix flux. The geochemical matrix flux occurred with similar patterns at the mesoscale level, or across the biogeochemical provinces. The element use efficiency (EUE) for Ca, Mg, Mn, Fe, Cu and Zn was greater (p < 0,001) in the FSU than in the VSU. This indicates a significant biogeochemical matrix flux effect in the successional forest ecosystem, contrary to the Virola surinamensis ecosystem with relatively low floristic diversity. Potassium (K) occurred with similar EUE values (p > 0,05) in both biological systems suggesting that the VSU ecosystem was an efficient K cycler. The forest floor stocks of K, Ca, Mg, Mn, Fe, Cu and Zn were higher (p < 0,001) in the FSU than in the VSU. This may be explained by the more diversified biogeochemical matrix control in the forest successional ecosystem. The overall water holding capacity was similar (p > 0,05) between ecosystems, although forest floor storage was higher (p < 0,001) in the FSU, indicating that the VSU ecosystem has recovered its structure and function over time. The biogeochemical matrix mean residence times for forest floor organic matter and K, Ca, Mg, Mn, Fe, Cu and Zn were higher (p < 0,001) in the successional ecosystem (FSU) than in the Virola surinamensis ecosystem (VSU). This suggests that in FSU the influence of forest floor stocks worked as a proximal factor, associated with the more distal factor of higher floristic diversity, which likely introduced recalcitrant substances into the system to minimize the decomposition process. The dispersion models illustrated in semivariograms for Al, Na, Fe and Cu in the Yellow Latosol dystrophic (LAd), and Ca in the Yellow Latosol dystrophic endocrecionary (LAdc) showed a nugget effect. In the LAd soil pedochemical system, the semivariograms models demonstrated spatial dependence, including H+ (spherical, r2 =0.92); Na (gaussian, r2 =0.49); K (gaussian r2=0.98); Ca (exponential, r2= 0.82); Mg (gaussian, r2 = 0.87); Mn (exponential, r2 = 0.86), Zn (gaussian, r2 =0.79). In the LAdc soil, cations that showed spatial dependence were Al (gaussian, r2 = 082); H+ (gaussian, r2 = 092); Na (gaussian, r2 = 0.87); K (gaussian, r2 = 0.86), Mn (gaussian, r2 0.96) and Fe (gaussian, r2 = 0.87); Cu (gaussian, r2 = 0.80) and Zn (gaussian, r2 = 0.79). Carbon dioxide (CO2) flux from soils in the were similar (p > 0,05) with values of 4,03 μmol C m-2 s-1 and 4,37 μmol C m-2 s-1 in the VSU and FSU, respectively. Based on the CO2 soil efflux, I conclude that the Virola surinamensis ecosystem attained similar metabolic processes in relation to the successional forest ecosystem over time.
Acesso aberto (Open Access)
Efeito da topografia e da precipitação na florística e na produção de liteira em Caxiuanã, Pará
(2015-12) FERREIRA, Laura Suéllen Lisboa; CATTANIO, José Henrique; JARDIM, Mário Augusto Gonçalves
The objective of this work was to study the effect of topography and rainfall in the structure of trees and litter production in a tropical rain forest in the National Forest of Caxiuanã. Were delimited three tranches of 1.000 m2 in each topographic levels (lowland, intermediate and plateau) and identified all individuals and collection of litter. For the three levels was recorded a total of 124 species belonging to 33 botanical families. The three families with higher importance value index for topographies of lowland and intermediate were Sapotaceae, Lecythidaceae and Chrysobalanaceae and for plateau were Lecythidaceae, Sapotaceae and Chrysobalanaceae. The species Lecythis idatimon Aubl., Rinoria guianensis Aubl. e Eschweilera coriacea (DC.) S.A. Mori. showed the greatest importance value indices for the three topographies. The seasonality affects significantly the litter production, showing the highest values at the end of rainy season and early dry season. The environmental stimulus for the fall of the leaves is mainly due to decrease in relative humidity, justified by the need of the plants to increase photosynthetic efficiency. The difference in population structure show strategies for flower production, and consequently the dispersion of fruits and seeds.
Acesso aberto (Open Access)
O efeito da topografia e microclima na florística e estrutura de árvores e na produção de liteira em uma floresta ombrófila densa na Amazônia Oriental
(Universidade Federal do Pará, 2012) FERREIRA, Laura Suéllen Lisboa; JARDIM, Mário Augusto Gonçalves; http://lattes.cnpq.br/9596100367613471; CATTANIO, José Henrique; http://lattes.cnpq.br/1518769773387350
The object this study was to study the effect of topography and microclimate (temperature and precipitation) in the floristic and structure of trees and litter production in a tropical rain forest in the National Forest Caxiuanã. In the grade of 25 km2PPBio, three areas were chosen (A, B and C) where plots were established 10 x 100 m, following the same topographic profile (lowland, intermediate and planteau). These plots, we identified all trees with DBH ≥ 10 cm for the realization of phytossociologic, taking into account the parameters of absolute and relative density, frequency and dominance, thus calculating the index value of importance (IVI). Micrometeorological temperature data were obtained from connected data logger Hobo Pro v2 and precipitation data were collected by the automatic station of IBAMA. We found 124 species in 33 plant families. The richest families in number of species were Sapotaceae (17), Chrysobalanaceae (10), Lecythidaceae (10) and Caesalpiniaceae (8). The most abundant families in number of individuals were Sapotaceae (65), Chrysobalanaceae (52) and Caesalpiniaceae (40). The area showed little floristic diversity evidenced by the low Shannon Diversity Index (H’= 3.16) and high uniformity in the proportions individuals/species within the plant community, given the degree of evenness of Pileou (J’= 0,94). There were no significant differences in richness and diversity of trees in relation to the plateus, intermediate ans lowland, as well as the density of species and basal area individuals. No there was a clear separation in the composition of tree species (DBH ≥ 10 cm) between the plots sampled in the plateau topographic condition, intermediate and lowland. The family with the higest IVI was Sapotaceae for the topography of lowland and intermediate, and Lecythidaceae for the plateau and species with higher IVI for three topographies were Lecythis idatiomon, Rinoria guianensis and Eschweilera coriacea. The average production of total litter in the nine plots was 758.59 kg ha-1. There was no significant difference in the production of litter in relation to topography and medium temperature and maximum temperature, but in relation to rainfall and minimum temperature there was differences. The leaf fraction (73,55%) was the most representative in the composition of litter, followed by branches (24,98%), fruits (3,88%) and flowers (3,85%). The flower production and fruits showed no significant relationship with the topography. No relationship was found in flower production with rainfall and temperature, but the fruits production showed significant differences with precipitacion and maximum temperature and minimum. The topography does not influence the floristic and structure of trees and litter production in the nine studied plots, but the variation in precipitation and temperature had a strong influence on litter production total and fruit production.
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)
Influência de variáveis meteorológicas na produção de liteira na Estação Científica Ferreira Penna, Caxiuanã, Pará
(Instituto Nacional de Pesquisas da Amazônia, 2009-09) SILVA, Rosecélia Moreira da; COSTA, José Maria Nogueira da; RUIVO, Maria de Lourdes Pinheiro; COSTA, Antonio Carlos Lôla da; ALMEIDA, Samuel Soares
The evaluation of the influence on the exclusion of rainfall on the variation of litter production was done in Caxiuanã Forest Reserve at Ferreira Penna Scientific Station (1º 42 ' S, 51º 31 ' W) during the period from March, 2001 to February, 2003 with the objective of identifying the main meteorological variables and the main components of the monthly water balance that affected the production and decomposition of litter. This work was part of the subproject EXPERIMENT OF DROUGHT IN THE FOREST (ESECAFLOR), that aimed to study the long term impacts of drought on the water, energy and carbon dioxide fluxes in the Amazon forest. The sazonality of total litter production and its components (leaves, brushwood and reproductive parts) was well established, with the occurrence of a greater litter production during the months with lower precipitation. The monthly litter production during the experimental period ranged from 294.78 kg.ha-1 to 1758.69 kg.ha-1, with an average of 777.70 kg.ha-1. The total litter production was partitioned in leaves (61.40 %), brushwoods (18.45 %) and reproductive parts (20.14 %). The results obtained in the undisturbed plot showed a higher litter production, about 25 %, compared to the litter production in the plot under the exclusion of water. The variables more strongly correlated with litter production and its components were wind speed, global solar radiation density flux, photosynthetic active radiation density flux, soil temperature at 5 cm depth, precipitation, soil water deficit and water surplus.
Acesso aberto (Open Access)
Organic material decomposition and nutrient dynamics in a mulch system enriched with leguminous trees in the Amazon
(2008-06) CATTANIO, José Henrique; KUEHNE, Ronald; VLEK, Paul L.G.
The new techniques proposed for agriculture in the Amazon region include rotational fallow systems enriched with leguminous trees and the replacement of biomass burning by mulching. Decomposition and nutrient release from mulch were studied using fine-mesh litterbags with five different leguminous species and the natural fallow vegetation as control. Samples from each treatment were analyzed for total C, N, P, K, Ca, Mg, lignin, cellulose content and soluble polyphenol at different sampling times over the course of one year. The decomposition rate constant varied with species and time. Weight loss from the decomposed litter bag material after 96 days was 30.1 % for Acacia angustissima, 32.7 % for Sclerolobium paniculatum, 33.9 % for Iinga edulis and the Fallow vegetation, 45.2 % for Acacia mangium and 63.6 % for Clitoria racemosa. Immobilization of N and P was observed in all studied treatments. Nitrogen mineralization was negatively correlated with phenol, C-to-N ratio, lignin + phenol/N ratio, and phenol/phosphorus ratios and with N content in the litterbag material. After 362 days of field incubation, an average (of all treatments), 3.3 % K, 32.2 % Ca and 22.4 % Mg remained in the mulch. Results confirm that low quality and high amount of organic C as mulch application are limiting for the quantity of energy available for microorganisms and increase the nutrient immobilization for biomass decomposition, which results in competition for nutrients with the crop plants.