Carlos Antonio Alvares Soares Ribeiro

Decomposition and nutrient release from leaf litter of Eucalyptus globulus grown under different water and nutrient regimes

Abstract Leaf litter from stands of Eucalyptus globulus Labill., of varying chemical composition was used to study decomposition rates and the release of nutrients (N, P, S, K, Ca, Mg). Leaf litter from control plots, which received no additional fertiliser or water (C), from fertilised plots (F), from irrigated plots (I) and from irrigated and fertilised plots (IL and ILN) was used. IL was collected during June–July and ILN during September. The C, F and I contained lower N and P than the IL and ILN, and had also a lower lignin content. Litterbags were used to study decomposition during a period of 643 days. The remaining ash free weight after 643 days of incubation ranged from 52.8% in C leaf litter to 47.9% in ILN leaf litter. The decomposition rates of leaf litter were 0.37 per year for C and 0.42 per year for ILN. Decomposition rates and weight losses were not significantly different among leaf litters, irrespective of different N and P concentrations, C/N ratios and lignin/N ratios. The concentration of N, S, and Ca in all substrates studied were higher at the end of the incubation period than at the beginning whereas the concentrations of K and Mg were lower. P concentration was lower at the end than at the beginning of the experiment, except for C leaf litter. The increase in N concentration was inversely correlated to its concentration in the original leaf litter. During the early decomposition stages (133 days), release of N, P and Ca was positively correlated to their initial concentration. Except for S and Ca, the amount of N, P, Mg and K remaining at the end of the experiment was similar to that determined after the early decomposition stages. The improvement of leaf litter quality through fertiliser application did not increase decomposition rate, but the release of N and P was enhanced.

Fine-root dynamics, soil moisture and soil carbon content in a Eucalyptus globulus plantation under different irrigation and fertilisation regimes

The minirhizotron technique was used to study the temporal dynamics of fine-roots over a 10 month period in a E~caZyprus plantation in central Portugal. Four treatments were applied: a control without irrigation or fertilisation (C), fertilisation twice per year (F), irrigated without fertilisation (I), and irrigated and fertilised once each week with fertiliser in the irrigation water (IL). In I and IL a drip-tube system was used, and fertiliser rates were adjusted based on the estimated plant nutrient demand. Soil moisture content was measured during the same period at 5 cm depth intervals down to 90 cm depth. Soil carbon content was measured at planting, 30 months after planting and 54 months after planting. Interrelations between fine-root dynamics, soil moisture, and soil carbon content are discussed. Fine-root counts peaked in late autumn in all treatments and declined thereafter until March. Fine-root growth in spring and summer seemed to be dependent on water supply; i.e. with an ample water supply (within rows, close to the drip-tubes in I and IL), root counts increased almost linearly between April and November. In the non-irrigated treatments (C and F, as well as between rows in I and IL), no marked increase in root counts occurred until late August, when it increased immediately after a heavy rain. Root growth in I was shallowest during spring and summer, while in F it was shallowest during autumn and winter. In general, treatment means of root counts were highest in IL, somewhat lower in I, and considerably lower in C and F. In addition to irrigation effects, treatment differences in soil water content were enhanced by differences in soil carbon content, which in turn could be attributed to root turnover, as reflected by the temporal dynamics of root counts. The carbon flow from the trees to the soil, which was probably associated mainly with root death, was highest in IL. Thus this treatment should have enhanced soil fertility.

Development of root biomass in an Eucalyptus globulus plantation under different water and nutrient regimes

The distribution along the soil profile of Eucalyptus globulus root biomass was followed in a plantation in central Portugal at 1, 2 and 6 years after planting, using an excavation technique. The experimental design consisted of a control (C) and 3 treatments: application of solid fertilizers twice a year (F), irrigation without the application of fertilizers (I) and irrigation combined with liquid fertilizers (IL). Below- and above-ground biomass decreased as follows: IL>I>F>C. So, water stress limited growth more severely than nutrient stress. The roots rapidly colonized the top soil volume (0–20 cm depth) during the first year after planting. Fine root biomass 6 years after planting was 2.2, 1.8 and 1.6 times higher in IL treatment than it was respectively in control, and in F and I treatments. The distribution of fine roots along the soil profile 6 years after planting was more even in IL compared to the other treatments. However, fine roots in the top soil were more concentrated along the tree rows in the irrigated treatments than in the others. The proportion of below-ground biomass relative to the total tree biomass and the root/shoot ratio were higher in C than in the treatments at early growth stages. This pattern was not so clear 6 years after planting, due to the increased proportion of the tap root relative to total biomass, especially in the IL treatment.

Spatial and temporal distribution of urban heat islands

The formation of an urban heat island (UHI) is one of the most common impacts of the urbanization process. To mitigate the effects of UHI, the planning of urban forests (e.g., creation of parks, forests and afforestation streets) has been the major tool applied in this context. Thus, the aim of this study is to evaluate the spatial and temporal distribution of heat islands in Vila Velha, ES, Brazil using the mono-window algorithm. The study followed these methodological steps: 1) mapping of urban green areas through a photointerpretation screen; 2) application of the mono-window algorithm to obtain the spatial and temporal patterns of land surface temperature (LST); 3) correlation between LST and the normalized difference vegetation index (NDVI) and normalized difference build-up index (NDBI); 4) application of ecological evaluation index. The results showed that the mean values of LST in urban areas were at least 2.34 to 7.19°C higher than undeveloped areas. Moreover, the positive correlation between LST and NDBI showed an amplifying effect of the developed areas for UHI, while areas with a predominance of vegetation attenuated the effect of UHI. Urban centers, clustered in some parts of the city, received the worst ecological assessment index. Finally, the adoption of measures to guide the urban forest planning within urban centers is necessary to mitigate the effect of heat islands and provide thermal comfort in urban areas.

Fuzzy logic applied to prospecting for areas for installation of wood panel industries

Prospecting for suitable areas for forestry operations, where the objective is a reduction in production and transportation costs, as well as the maximization of profits and available resources, constitutes an optimization problem. However, fuzzy logic is an alternative method for solving this problem. In the context of prospecting for suitable areas for the installation of wood panel industries, we propose applying fuzzy logic analysis for simulating the planting of different species and eucalyptus hybrids in Espírito Santo State, Brazil. The necessary methodological steps for this study are as follows: a) agriclimatological zoning of different species and eucalyptus hybrids; b) the selection of the vector variables; c) the application of the Euclidean distance to the vector variables; d) the application of fuzzy logic to matrix variables of the Euclidean distance; and e) the application of overlap fuzzy logic to locate areas for installation of wood panel industries. Among all the species and hybrids, Corymbia citriodora showed the highest percentage values for the combined very good and good classes, with 8.60%, followed by Eucalyptus grandis with 8.52%, Eucalyptus urophylla with 8.35% and Urograndis with 8.34%. The fuzzy logic analysis afforded flexibility in prospecting for suitable areas for the installation of wood panel industries in the Espírito Santo State can bring great economic and social benefits to the local population with the generation of jobs, income, tax revenues and GDP increase for the State and municipalities involved. The proposed methodology can be adapted to other areas and agricultural crops.

Markov chains and cellular automata to predict environments subject to desertification

The foremost objective of this study was to analyze the performance of a Markov chain/cellular automata model for predicting land use/land cover changes in environments predisposed to desertification. The study area is the Vieira river basin, located in Montes Claros (MG, Brazil). Land use/land cover prognosis was performed for the year 2005 so that this result could be compared with the ranked image for the same year, taken as ground truth. Kappa indices were used to evaluate the change level that occurred between these two cases. Results from cellular automata were evaluated from those of the Markov chain model. The latter proved to be efficient in the quantitative prediction of changes in land use/land cover. Regarding the cellular automata, an average performance was noted in the spatial distribution of classes. Specifically, with regard to desertification, the use of the CA-Markov model was effective at estimating the total area of the most susceptible class to this process, Bare Soil; however, it was inefficient in its spatialization. Even with the caveats related to the performance of cellular automata, the overall prediction capacity of CA-Markov models can be considered as good.

A new methodology for royalties distribution of the Itaipu hydroelectric plant: The hydrographic basin as the unit of analysis

Over the past few years, many sectors such as energy generation, industry, domestic supply, and agriculture have encountered serious environmental problems due to the lack of rainfall. Thus, the purpose of this paper is to review the current methodology of royalties distribution from Itaipu hydroelectric plant. In the proposed approach, two criteria were considered to establish the division of Itaipu royalties: (1) the relative percentage of the water flow in the generation of electricity and, (2) the relative percentage of the drop in the height of water. 62 hydroelectric plants were evaluated in this study. In 52 plants the water flow was the factor that most contributed to the generation of electricity. In 2013, 346 municipalities benefited the Itaipu royalties. With the proposed methodology, 1,327 municipalities will receive the resource, what would increase the revenue of each of these municipalities by, on average, US

Aplicação da geotecnologia no estudo de cadastro técnico rural e no mapeamento de áreas de preservação permanente e reservas legais

87,436.91 per year. The methodology presented herein proposes a reduction in the environmental disparity that now exists in Brazil, through improvement to Government instruments and environmental policies. The distribution of royalties throughout the watershed can provide additional resources to support payment programs for environmental services at the state and municipality levels.

Changes in carbon stocks in Eucalyptus globulus Labill. plantations induced by different water and nutrient availability

Este trabalho teve como objetivo principal mapear as classes de cobertura e o uso da terra, bem como as areas de preservacao permanente (APPs) e de reservas legais de imoveis rurais. A area de estudo compreendeu parte dos municipios de Canaa, Araponga e Ervalia, Estado de Minas Gerais. Foi utilizada uma imagem ortorretificada de alta resolucao do sensor Ikonos II com 1 m de resolucao espacial. A partir da interpretacao visual da imagem, foram criadas sete classes tematicas, a saber: cobertura florestal, pasto sujo, pasto limpo, cafezal, edificacoes, area agricola e reflorestamento. As APPs foram obtidas a partir de um modelo digital de elevacao hidrologicamente consistente. Os resultados mostraram a predominância das classes de cafezal com 24,5% e de cobertura florestal com 28,8%, perfazendo mais de 50% da area de estudo. As areas delimitadas como de preservacao permanente totalizaram 55,1%.