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In terms of some specifics parameters, Eucalyptus and savanna trees were characterized by similar responses of resource use under field conditions. Remarkably, young eucalypt exhibited greater photosynthetic capacity, primarily in the dry season. Although a growing demand for paper and pulp is enhancing pressure for land use to increase eucalypt plantations in tropical savanna regions around the world, it has not been thoroughly characterized to date how eucalypt plantations perform in terms of energy, water and CO2 assimilation exchange compared to native savanna species. In this study, we performed an integrative analysis of diurnal changes in gas exchange, chlorophyll fluorescence (Fv/Fm) and water use efficiency of eucalypt and savanna species over a whole year in the Brazilian tropical savanna region in eastern Mato Grosso do Sul State. We also evaluated the response curves of net photosynthetic rate (A) in response to photosynthetic photon flux density in leaves of these species during both wet and dry seasons. Although dry season conditions led to decreases in all parameters, primarily in stomatal conductance (gs), Fv/Fm values remained above the level that causes photoinhibition. Young eucalypt exhibited mostly similar Amax values in wet and dry seasons, but adult eucalypt and savanna trees decreased their Amax by 83% and 69% in the dry season, respectively. Overall, all species were similar in photosynthetic terms and intrinsic water use efficiency (WUEi), as demonstrated via principal component analysis. Despite major differences between wet and dry seasons, eucalypt plantations and savanna woody species were characterized by similar responses of resource use efficiency under field conditions. Remarkably, young eucalypt was characterized by higher photosynthetic capacity, particularly during the dry season.

Scientific communication in agricultural and forest meteorology requires a correct conversion of units and the adequate use of equations. In general, most of conversion and equations are found separately in a specific book, paper or document. Thus, here we propose a single document with conversion units of solar radiation, evapotranspiration, resource use efficiency, carbon balance, ecophysiology, trace gases and water; and general equations: Penman-Monteith, canopy conductance, decoupling factor and Bowen ratio. This document has a lot of value for teaching, for scientists and as a quick reference.

Em várias localidades não existem registros horários de temperatura do ar, o que dificulta a elaboração de vários estudos sobre a aptidão agrícola de várias espécies e cultivares. O objetivo do presente trabalho foi determinar por meio de registros horários de temperatura do ar o número de horas de frio (NHF) inferiores a 7ºC, 10ºC e 13ºC em três localidades de Minas Gerais, e correlacioná-las com a temperatura mínima e máxima média mensal para identificar as potencialidades dessas variáveis em estimar o NHF. Utilizaram-se para este estudo dados horários de temperatura do ar dos municípios de Belo Oriente, Antônio Dias e São Domingos do Prata - MG, durante o período de junho de 2001 a dezembro de 2007. A localidade de Antônio Dias apresentou os menores valores de temperaturas do ar e maior número de horas de frio, quando comparada com as demais localidades, enquanto que a localidade de Belo Oriente apresentou as maiores temperaturas e o menor número de horas de frio. As variáveis temperaturas médias mensais mínima e máxima do ar correlacionaram-se bem com o NHF < 13 °C em todas as localidades, não acontecendo o mesmo com o e o NHF < 10 °C e NHF < 7 °C que apresentou valores muitos fracos ou não significativos de correlação. As variáveis temperatura mínima e máxima médias mensais do ar podem ser utilizadas para estimar o NHF < 13 °C.

Manaus se localiza na parte central da bacia Amazônica e apresenta as melhores séries de dados disponíveis da região de floresta tropical brasileira. A região de Manaus apresenta media anual de chuva de 2107mm no período 1911-1985. Tendo o período chuvoso (dez-maio) 1546mm, e o período seco (jun-nov) com 516mm. No mês mais úmido (março) não se observou precipitação em 24% dos dias no mais seco (agosto) em 51% dos dias. Nota-se, que as chuvas em cerca de 80% dos casos e igual ou inferior a 15mm. Os sistemas que ocasionam chuvas são os mesmos ao longo do ano, diferenciando as variações estacionais apenas pelo número de mecanismos de precipitação ocorrentes em função da água precipitável e do balanço de energia local. Os períodos mais úmidos foram aqueles em que se verificou, de maneira geral os períodos mais úmidos foram aqueles em que se verificou, temperatura menores. No inicio do século ate 1930 observaram-se menores precipitações em relação ao restante do período com comportamento inverso para as temperaturas máximas, mínimas e medias. Isto explica a tendência crescente para a precipitação decrescente para a temperatura média. Analisando-se a precipitação e a temperatura média anual nos períodos 1931-60 e 1961-85, verificou-se a tendência desses elementos flutuarem flutuaram em torno de um valor médio. Portanto, para as series de dados analisados, parece não existir tendência recente de mudança climática. Manaus is in the geographical center of the Amazon Basin and has the best available data series of the Brasilian Tropical Forest. That region displays an annual rainfall average of 2107mm over the period 1911-1985, while the rainy season (december-may) has a mean of 1546mm and the dry season 516mm. In the moister month (march) , it was not observed precipitation over 24,4% of the days and in (august), the dryer month 51,3% of the days. It was noted that 77,7% of the rainfalls is equal or lesser than 15mm. The rainfall systems are the same throughout the year differing the season, deffer only by the number of precipitation that occur as a function of the available water and of the localenergy balance. In general, the moister period had lower temperatures. At the beginning of this century (until 1930) were lower anual precipitations observed than the remaining of the period, with invese behavior with the maximum, minimum and mean temperatures. This explain the increasing trend in the precipitation but decreasing of the mean temperature. Analysing the annual precipitation and the mean temperature over 1931-1960 and 1961-1985, there was no defined trend, the temperature varying about the mean value. Therefore, no recent trend of climate change could be detect in data series used in this study.

Objectives The use of consolidation chemotherapy (CCT) after chemoradiation (CRT) in cervical cancer remains debatable. We evaluated the impact of CCT added to up-to-date CRT (CRT) and sought to identify predictive factors of CCT benefit. Methods This retrospective study reviewed 216 patients with 2014 FIGO stage IB2-IIA2, and IIB-IVB (para-aortic nodes only) cervical cancer treated with CRT alone or CRTT followed by CCT (CCT group). Firstly, we assessed the prognostic role of CCT. Moreover, we developed a prognostic score for distant metastasis free survival (DMFS). Results After 42.8 months of median follow up 174 patients were treated with standard CRT and 72 with CCT. Clinical characteristics were comparable between groups, except CCT patients were younger (p 1 but not for patients with score ≤1 (OS: p=0.310; DMFS: p=0.179). Conclusions A clinical score may predict CCT benefit. If this score withstands external validation, it may contribute to better selection for CCT.

As Brazil becomes one of the largest agricultural and livestock producers, the expansion of cultivated pasture and crop areas in the Cerrado region is expected to cause significant changes in carbon and water vapor fluxes. While this change in land use promotes modifications in regional carbon uptake and water cycle, eddy covariance studies carried out in pasture areas in the Brazilian Cerrado remain scarce. The present study aimed to quantify the carbon uptake and water vapor exchange of these areas in the Brazilian Cerrado. The experimental site was installed in an area covered by Brachiaria sp. in Tres Lagoas – MS, Brazil. Data were collected during two hydrological years (2016–2017 and 2017–2018). Pasture strongly acted as a carbon sink; its total accumulation reached −208.9 (±9.6) and −171.8 (±15.8) g C m−2 in the first and second hydrological years, respectively. Average evapotranspiration of 2.0 (±1.1) mm d−1 was observed in the two hydrological years. There was significant reduction in evapotranspiration at the pasture site during the driest months of the year (June and July), mainly in the second hydrological year, which recorded an average of 0.4 (±0.1) mm d−1. The lower recorded water availability in the soil led to the release of 86.7 g C m−2 (over 85 days) in the dry season of the second hydrological year. Ecosystem-level water use efficiency observed during the higher soil water deficit facilitated the survival of the grass. This information is the basis for further studies about the impact of climate change on carbon uptake and water vapor flux by cultivated and natural pasture; additionally, the present research will allow comparisons of carbon storage results to other ecosystems and to support studies of agrometeorological modeling.

The objective of this study was to estimate the Leaf Area Index (LAI) by indirect methods in plantations of Eucalyptus clones in two distinct physical-climatic sites, during the dry and rainy periods. The study was performed in four young and adult Eucalyptus stands, located in Rio Doce basin, eastern Minas Gerais state (Brazil) situated in areas of lower and higher altitudes. Nine plots were allocated in each stand. Experimental data were collected in months representing the driest and the wettest periods. LAI indirect measurements were performed using the LAI-2000 equipment and cameras with hemispherical lens. To verify the accuracy of estimation, a destructive analysis was also performed. The LAI measurements by the LAI-2000 was the one which best correlated with the observed LAI (R =0.90), although the hemispherical photos had presented good potential use. It is verified that the LAI of stands in the higher altitudes region, surpassed those of lower altitudes, which was also observed by the indirect methods. The destructive analysis indicates lower values of LAI measured in the dry season although this variation is only significant for higher altitudes. This behavior is also observed for estimates with the LAI-2000, different from the hemispherical photographs which did not identify seasonality of LAI. O objetivo deste estudo foi estimar o Índice de Área Foliar (IAF) por métodos indiretos em plantios clonais de eucalipto em dois distintos sítios físico-climáticos, durante as estações seca e chuvosa. O estudo foi feito em quatro talhões, dois jovens e dois adultos, localizado na bacia do Rio Doce, leste de Minas Gerais, situados em áreas de baixas e altas altitudes. Nove parcelas foram alocadas em cada talhão. Dados experimentais foram coletados em períodos secos e chuvosos. As medidas indiretas do IAF foram feitas usando o LAI-2000 e câmeras com lentes hemisféricas. Para verificar a precisão da estimativa foi realizada a análise destrutiva. As medias do LAI-2000 foram aquelas que melhores correlacionaram com os dados de IAF observados (R=0,9), embora as fotos hemisféricas apresentem bom potencial de uso. Foi verificado que os valores de IAF dos talhões de maiores altitudes foram maiores comparados às regiões baixas, o que também foi observado pelos métodos indiretos. A análise destrutiva indica baixos valores de IAF medidos na época seca, embora esta variação seja significativamente somente nos talhões das regiões mais altas. Este comportamento é também observado nas estimativas do LAI-2000, diferente das fotografias hemisféricas que não identificaram a sazonalidade do LAI.

The rapid expansion of Eucalyptus plantations in Doce river basin, eastern Brazil, by changing the grassland and the natural surface cover in the savanna ecosystem, can potentially cause significant changes to water resources of the region. Especially for the higher amount of water transpired by the trees. The objective of this work was to model the water balance in an area cultivated with clonal E. grandis × urophylla in the Doce river basin, state of Minas Gerais, Brazil. Between October 2007 and September 2010, the water balance model estimated the daily variation of available soil water as a function of the water loss via evapotranspiration. Components of the evapotranspiration process were estimated by modifying the stomatal resistance of the Penman-Monteith equation. Evapotranspiration (ET) and precipitation (P), during the three years, were 3,467 mm and 3,439 mm, respectively. The evapotranspiration/precipitation ratio (ET/P) was of 1.01. Precipitation input was approximately balanced by water losses to evapotranspiration, without significant changes to water stored in soil and groundwater.

The objective of this study was to analyze the interaction between the sugarcane with the surrounding atmosphere, by means of the decoupling factor (Ω), for five different growth periods and among irrigation events. The study was carried out in an experimental area, located in the region of Lower Middle part of the Sao Francisco Valley of Brazil. The data used for estimating of Ω were obtained from sensors accommodated on a micrometeorological tower, which was installed inside the experimental area cultivated with sugarcane ratoon crop It was observed that, at the beginning of the crop cycle (70 to 95 days after cutting, DAC), the average value of Ω parameter was 0.74, due to reduced values of plant height and leaf area index, as well as due to the high values of wind speed that reduced the interaction between the sugarcane and the adjacent air. A similar mean value was verified in the period from 309 to 338 DAC, which occurred during the rainy season, due to the evaporation of the water deposited on the canopy. The lodging of the sugarcane plants, which was noticed in the period from 218 and 248 DAC, as well as irrigation suspension at the end of the cycle (339 to 378 DAC), promoted reduction in the mean values of Ω (0.61 and 0.69, respectively).

SUMMARYA micrometeorological experiment was carried out in an area of soyabean cultivation located in northeastern Para state, Brazil, in order to evaluate impacts on the local energy balance due to replacement of forests by soyabean. The meteorological data from forest ecosystems were collected in Caxiuanã forests located in central Para. The energy balance components were obtained using the Bowen ratio technique. Differences in energy balance components between ecosystems were significant during the soyabean growing season and more significant between growing seasons. During the soyabean growing season mean impacts of −15%, −9% and −27% on net radiation, latent heat flux (LE) and sensible heat flux (H), respectively, were observed. At specific soyabean stages, LE was higher than in the forest because of the high soyabean surface conductance of water vapour. However, during the production off-season the impacts were more significant (p < 0.05), showing a reduction of 78% in LE and a substantial increase in H (84%) because of the absence of vegetation cover over this period.

Este trabalho teve como objetivo definir sítios ambientais homogêneos no Estado do Espírito Santo, a fim de indicar o uso potencial do solo de todo o seu território. Técnicas estatísticas multivariadas foram empregadas sobre informações do relevo, coordenadas geográficas, dados do solo e clima. A disponibilidade hídrica e a evapotranspiração real e potencial foram determinadas a partir do resultado do balanço hídrico climatológico. Inicialmente, foi executada a análise de componentes principais (ACP) sobre os dados climáticos e, em seguida, a de agrupamento nas informações do relevo, solo, nos escores climáticos provenientes da ACP e nas coordenadas geográficas. Os dois primeiros eixos da ACP explicam cerca de 85,3% da variância total acumulada. Após a rotação dos componentes principais, as melhores variáveis correlacionadas ao primeiro eixo foram a amplitude térmica, a temperatura média anual, seguida da evapotranspiração real. Foram definidos seis sítios ambientais para o Estado do Espírito Santo e alguns apresentaram similaridades ao clima. As variáveis topográficas foram os fatores de maior influência na diferenciação dos sítios. A metodologia se mostrou adequada na definição dos sítios. The objective of this study was to define homogeneous environmental sites in the state of Espírito Santo, Brazil which may possibly be used to indicate potential soil use for the entire state. Multivariate statistics techniques were employed using information of the relief and geographical coordinates, as well as soil and climatic data. Water availability and real and potential evapotranspiration were determined from the results of the climatological water balance. Initially a principal component analysis (PCA) for the climatological data was performed. Subsequently, a grouping analysis was executed on the relief, soil and climatic data provided by the PCA and geographical coordinates. The first two axes of the PCA define roughly 85.3% of the total accumulated variance. After rotation of the principal components, the variables that best correlated to the first axis were the thermal amplitude, average annual temperature, followed by real evapotranspiration. Six environmental sites were defined for the state of Espirito Santo, some presenting climatic similarities. The topographic variables were the factors of greatest influence on the sites differentiation. The methodology was appropriate in defining the sites.

Enhanced Vegetation Index images are made by means of bands in the electromagnetic spectrum in the range of blue, red and near infrared. This index minimizes the response effects of soil and atmosphere, besides having high response to phenological variations. This study aims to use the vegetation index modified to characterize the spectrum and temporal behavior of different uses of soil in the State of Espirito Santo – Brazil between June 200 and June 2008. All together, a 16-day series summarizing 192 index images was generated. Random points with good spatial distribution were generate and ranked according the type coverage, using LANDSAT/TM images. The results show that the Enhanced Vegetation was sensitive to the phenological variations of the vegetation, with lower values for the dry season in relation to the rainy season. Similar spectrum behavior was also observed among the different uses of soil for both the Natural Forest and Planted Forest. The lowest index values were found for the category which includes the water bodies very close to the unit.

Este trabalho constitui a ultima parte do estudo que objetivou calcular o consumo de água em plantios de eucalipto. Nesta parte, modelou-se a resistência estomática em função das variáveis ambientais irradiância solar global, déficit de pressão de vapor e temperatura. Com a resistência estomática modelada a partir dos valores observados no artigo anterior, foi possível calcular a transpiração do eucalipto pelo método Penman-Monteith em alguns dias, nos períodos úmido e seco do ano. Verificou-se a existência da correlação entre a resistência estomática e as variáveis ambientais. Os modelos gerados nessa relação mostraram-se eficientes para calcular as variações diárias resistência estomática e também totais horários e diários de transpiração. This paper concludes the last part of the work aimed to calculate water consumption in eucalypt plantations. Stomatal resistance was modeled as a function of the following ambient variables: global solar irradiance, vapor pressure deficit and temperature. Based on stomatal resistance modeled from the values observed in the first part of this work, eucalypt transpiration by the Penman-Monteith method could be calculated in some days during the humid and dry periods of the year. Correlation between stomatal resistance and ambient variables was verified. The models generated by this relation proved efficient in calculating the diurnal variation of stomatal resistance as well as hourly and daily transpiration totals.

Devido ao grande interesse sobre a necessidade hídrica em cultivos de eucalipto e qual a resposta da planta às condições ambientais, esta pesquisa teve como objetivo calcular o consumo de água em plantios de eucalipto com 2 anos de idade. O trabalho foi composto por duas partes, sendo a primeira dedicada à determinação da condutância estomática em clones de Eucalyptus grandis x Eucalyptus urophylla irrigados e não-irrigados e à verificação do efeito da variação sazonal das varáveis ambientais. A segunda parte compreendeu a modelagem da resistência estomática e o cálculo da transpiração pelo método de Penman-Monteith. O sítio experimental localizava-se no Município de Belo Oriente, Estado de Minas Gerais, a 19(0)18'23" S de latitude, 42(0)22'46" W de longitude e 220 m de altitude. Na primeira parte, a condutância estomática foi medida em três períodos diferentes: período úmido, início do período seco e período seco. Valores médios da condutância estomática variando entre 0,41 e 0,22 mol m-2 s-1 no plantio irrigado e entre 0,38 e 0,24 mol m-2 s-1 no não-irrigado foram encontrados. Também, verificou-se que a condutância estomática sofreu variação entre os períodos úmido e seco, a qual foi relacionada com algumas variáveis ambientais e umidade do solo. In response to the growing interest in hydric need in eucalypt plantations and plant response as a function of environmental conditions, this work aimed to calculate water consumption in 2-year-old Eucalyptus grandis x Eucalyptus urophylla clones located both on irrigated and non-irrigated plantations. This work is divided into two parts. In the first, stomatal conductance is determined and the effect of seasonal variability of environmental variables is verified. In the second, stomatal resistance is modeled and eucalypt transpiration is calculated by the Penman-Monteith method. The experimental site was located in Belo Oriente, Minas Gerais, at 19º 18'23" S latitude, 42º22'46" W longitude and 220 m altitude. Stomatal conductance was measured in three different periods: humid period, early dry period, and dry period. Average values of stomatal conductance ranged from 0.41to 0.22mol m-2 s-1 for the irrigated treatment and from 0.38 to 0.24 mol m-2 s-1 for the non-irrigated treatment. Stomatal conductance was also found to decrease between the humid and dry periods. This variation was related with some environmental variables and soil moisture.

Coffee is native to shady environments, but often grows and yields better without shade. Thus, it may be reasoned that coffee leaves should display enough plasticity to acclimate themselves to contrasting light environments. However, little is known about mechanisms associated with such plasticity in coffee. This work aimed, therefore, to explore differences in leaf photoprotective mechanisms. Plants were grown in the field and received either 48 or 100% natural light. Evaluations were made using outer leaves from the sun-facing sides of the coffee hedgerow in Viçosa (Brazil) in August and October, when growth and photosynthetic rates are expected to be minimal and maximal, respectively, and in December, when temporary depressions in those variables are common. Regardless of light treatments, coffee leaves showed: (1) very low photosynthetic rates (generally below 2.5 μmol m−2 s−1), (2) chronic photoinhibition in August (dry, cool season) that was accompanied by strong loss of pigment concentration, and (3) discrete, dynamic photoinhibition in October and December (rainy, warm season). Compared with shaded leaves, sunlit leaves generally exhibited lower pigment concentration, lower quantum yield of electron transport, steeper inclinations and similar electron transport rate. Total ascorbate pool tended to be larger in sunlit than in shaded leaves (but with similar redox state), whereas activities of key antioxidant enzymes, as well as malondialdehyde accumulation and electrolyte leakage, were similar between those leaf types. As a whole, the photosynthetic apparatus of the coffee tree showed a low phenotypic plasticity to varying irradiance.

It was aimed in this work, through the geospatialization, the identification of the apt, restricted and inapt regions for cultivation of coffee (Coffea arabica L.) in Rio Doce watershed. It was used for such, temperature and water deficit data of 50 meteorological stations installed in the watershed and in bordering watershed. The data of water deficit were determined using the water balance according to Thornthwaite & Mather (1955). They were identified equivalent regions the one third of the watershed, located in the central part and in the northeast of the same, as being inapt to the cultivation of coffee, according to the productivity criterions related with the thermal and hydric demands of culture.

Analisou-se a produtividade de povoamentos de eucalipto, localizados nas regiões Belo Oriente, Nova Era e Guanhães, situadas na Bacia do Rio Doce, em Minas Gerais. Estudaram-se as precipitações ocorridas nas estações chuvosas e os componentes do balanço hídrico de Thornthwaite e Mather (1955), relativos ao período de janeiro de 1985 a dezembro de 1998, objetivando estudar a influência desses componentes com o ganho de volume médio anual de madeira (m³ ha-1). Para tal, utilizaram-se dados do inventário florestal da Empresa Florestal Celulose Nipo-Brasileira - CENIBRA, relativos à idade de três a sete anos. A produtividade de madeira foi influenciada pelo total precipitado na estação chuvosa (PEC). Os menores valores de incremento periódico mensal (IPM) foram observados nos anos precedidos de estação chuvosa seca (S) ou muito seca (MS), sendo que os maiores valores de IPM ocorreram nos anos precedidos de estações chuvosas, classificadas como chuvosa (C) ou muito chuvosa (MC). Considerando que tal fato foi mais pronunciado em Guanhães e Nova Era, verificou-se a correlação da PEC, finalizada em cada ano, com o IPM nos períodos de aumento (1986 a 1992) e diminuição na PEC (1992 a 1995), sendo que essas correlações atingiram um r² superior a 80%. Para um aumento de 100 mm na PEC de um ano para outro, o aumento no IPM foi, em média, de 0,445 m³ha-1mês-1, enquanto para uma redução de 100 mm a diminuição no IPM foi de 0,64 m³ha-1mês-1, para as duas regiões. Guanhães apresenta o maior índice de local médio, assim como a maior produtividade média, seguindo-se Nova Era e Belo Oriente. The productivity of eucalyptus stands found in Belo Oriente, Nova Era and Guanhães areas in the Rio Doce Basin, Minas Gerais State were analyzed. The precipitation events occurred over the rainy seasons as well as the water balance components by Thornthwaite and Mather, in 1955, relative to the period from January 1985 to December 1998 were studied, in order to determine the influence of these components on the gain of the annual average volume of wood (m³ha-¹). To do so, the forest inventory data from the Empresa Florestal Celulose Nipo-Brasileira - CENIBRA, relative to the 3 - 7 year age range, were used. Wood productivity was affected by the total precipitation in the rainy season (PEC). The lowest values of the monthly periodic increment (IPM) were observed in those years preceded by dry (S) or very dry rainy season (MS), whereas the highest IPM values occurred in those years preceded by rainy season so-classified as rainy (C) or very rainy (MC). Taking into account that this fact was more pronounced in both Guanhães and Nova Era, the correlation between PEC finished at every year and IPM for either the increase (1986 to 1992) and decrease periods (1992 to 1995) in PEC were verified; these correlations reached a r²above 80%. For a 100 mm increase in PEC from a year to another, the increase in IPM averaged 0.445 m³ha-1mo-1, whereas for a reduction of 100 mm the decrease in IPM was 0.64 m³ha-1mo-1 for both regions. Guanhães showed the highest average site index as well as the highest average productivity, following the Nova Era and Belo Oriente regions.

Com este trabalho objetivou-se desenvolver um sistema automático e monitorado de regionalização da demanda de irrigação suplementar das principais culturas irrigadas no Estado de Minas Gerais, disponibilizando tais informações via rede mundial de computadores (Internet) com três atualizações semanais. O sistema, denominado IRGNET, utiliza dados de estações climáticas automáticas do Instituto Nacional de Pesquisas Espaciais (INPE) para estimativa da perda de água pela cultura por evapotranspiração e a reposição da água no solo, pela precipitação. Utilizou-se um sistema de informações geográficas para espacializar e gerar mapas temáticos de evapotranspiração de referência e de precipitação diária do Estado e se desenvolveu um programa computacional para calcular o balanço hídrico e determinar a lâmina de irrigação para qualquer localidade do Estado. This study had the aim to develop an automatic and controlled system of regionalized supplemental irrigation demand for the main irrigated crops in the State of Minas Gerais by providing this information three times a week by the World Wide Web (Internet). The so-called IRGNET system uses data collected by automatic weather stations belonging to the National Institute for Space Research (INPE) for the assessment of water loss in crop evapotranspiration and also the water supply by rainfall. A geographic information system was used to spatialize and create thematic maps about crop evapotranspiration and daily rainfall in the State. A computer program was also developed to calculate the soil water balance and to determine the irrigation water depth for any place within the State.

Solar energy is among the renewable energy sources that received greater addition in installed capacity. However, it accounts for a small fraction of the energy matrix of most countries. Electric energy generation by solar systems can be improved through tracking. This work aimed to develop and compare a closed and an open loop solar tracking system. The closed loop system was developed using Light Dependent Resistors. An algorithm was developed for the open loop tracker as a function of the geometric relation between the sun and the photovoltaic module. A simulation was run to compare this algorithm with a system using tracking at fixed time intervals, for clear sky conditions, with different tracking parameters and for five different latitudes. No significant difference was observed between the proposed open loop tracking algorithm and the fixed time interval algorithm for the tracking parameters evaluated. The open and closed loop solar tracking systems were compared experimentally in Rio das Ostras, Brazil (22.49 °S 41.92° W). An average gain of 28.5% was observed for the open loop tracking system over a latitude tilted system and 33.0% for the closed loop tracking system.

Although the 3-PG model is widely used for forest productivity calculations, there are processes that do not present appropriate physical treatment. The aim of this study was to generate a tool to improve the water balance calculation in the model to enhance the energy balance and transpiration process. The calculation of transpiration was modified to account for variations in solar radiation with the inclination and azimuth of the terrain; the vapor pressure deficit was changed based on the relative humidity and air temperature; and the stomatal conductance varied according to solar radiation, vapor pressure deficit and air temperature. The water storage in the soil varied with the depth of the root system and the total water availability (TWA) in the soil. The assessment was also changed from a monthly to an hourly basis. The study was conducted in areas surrounding Cenibra, and the data were collected from the Rio Doce river basin, in the Brazilian state of Minas Gerais. Taken together, these modifications improved growth - modeling processes and enhanced the capacity of this analytical tool to differentiate intra - region productivity.

The return of water in vapor form from the land to the atmosphere, via plant transpiration and evaporation, is fundamental for the maintenance of the regional water cycle in the Amazon basin. Whereas transpiration, the dominant process, has the extensive vegetation cover as a large single source, evaporation can have several sources, and their relative importance and location are poorly known. The isotopic composition (δ18O and δD) of water from various sources was used to see whether or not specific sources of water vapor to the atmosphere could be determined. It is well established that natural waters fall on a line called the meteoric water line (MWL; the regression of δ18O × δD), with slope equal to eight and an intercept equal to ten. When a water body loses water via evaporation the slope become smaller than eight, typically 5–6. We estimated the slope of the regression of δ18O × δD for several potential sources. We analyzed 1273 samples: 500 of rainfall, 409 of river water, 134 of lake water, 164 of soil water, 40 of throughfall and stemflow water, and 26 of shallow ground-water. We found that large rivers and lakes are likely contributors of evaporated water to the atmosphere. However, as they cover only a small area of the basin, other sources are needed. Probably, evaporated water originates from several small sources that were not detected by the isotopic composition of our data.

The Amazon is the largest stream in the world. Its basin covers at least 7 · 10 6 km 2 , which represents ∼ 5% of the global continental area and almost 70% of the area of the continents localized in the equatorial zone, between 5°S and 5°N of latitude. The global tropical moist forest covers ∼ 9.35 · 10 6 km 2 , so that the Brazilian evergreen rain forest represents at least 50% of this area. At Obidos, the most accessible downstream station for collecting data, the area concerned is 4.619 · 10 6 km 2 . The purpose of these two extended abstracts is to show how changes and oscillations of climate can significantly affect erosion as well as carbon and nitrogen cycles, and may also mask the degradations of the environment due to deforestation.

This study was conducted based on data from 50 climatological stations, with the objective of evaluating the performance of two rainfall spatialization methods in the State of Alagoas, using two interpolation methods: Inverse Distance Weighting (IDW), with an exponent of 2, and Spline. The space distribution of the interpolated data and the accuracy of the interpolators were verified through the method of cross-validation. Both methods were shown to be appropriate in accomplishing the interpolation; however, some expressive differences were observed. The IDW method is recommended for underestimating the value of precipitation in 2.2 mm, while Spline overestimated it by 4.3 mm. In face of the necessary safety for agricultural planning, the use of the IDW method is then recommended, as it also presented the lowest standard deviation of the mean, representing a smaller margin of error

[1] In the last two decades, the strong increase of pasturelands over former rainforest areas has raised concerns about the climate change that such change in land cover might cause. In recent years, though, expansion of soybean croplands has been increasingly important in the agricultural growth in Amazonia. In this paper we use the climate model CCM3 to investigate whether the climate change due to soybean expansion in Amazonia would be any different from the one due to pastureland expansion. The land component of the model has been updated with new findings from the Large-Scale Biosphere Experiment in Amazonia (LBA), and a new soybean micrometeorological experiment in Amazonia. Results show that the decrease in precipitation after a soybean extension is significantly higher when compared to the change after a pastureland extension, a consequence of the very high albedo of the soybean.

Geostatistics evaluates the spatial dependence between two or more variables in order to estimate unknown values in space. The objective of this study was to evaluate, using geostatistical techniques, the spatial variability of dendrometric characteristics for a commercial plantation of Eucalyptus grandis x Eucalyptus urophylla located in eastern Minas Gerais, Brazil (19o28' S and 42o49' W). The diameter at breast height (DBH) and commercial height (H) of 60 trees was measured in a forest inventory plot at two, five and seven years old. The volume of each tree in the plot was estimated from allometric equations and values of DBH and H. Spatial dependence of the three dendrometric variables at different ages was evaluated by fitting the experimental semivariogram. Validation of the semivariograms was performed using the jackknife test. The dendrometric variables analyzed presented normal distribution throughout the entire production cycle according to the Kolmogorov-Smirnov test. The spherical model adequately represented the spatial distribution of dendrometric characteristics for the planted forest. The dendrometric characteristics of the analyzed plantation had an average spatial dependence, making the use of geostatistical techniques for characterization of the plantation very important.

The knowledge of the Photosynthetically Active Radiation (PAR) is important to different areas of vegetal physiology and agricultural sciences. Estimation models of the PAR based on the Global Radiation (GR) are extremely useful, since the GR is conventionally measured at the meteorological stations. Thus, the seasonal variability of the relationship PAR/GR was analyzed in five areas located at the river Doce basin, Minas Gerais State, Brazil, considering the dry and wet periods of the years 2001 to 2004. The relationships PAR/GR obtained for the dry and wet periods, and also to all data, presented agreement with those ones determined by several researchers in different areas of the world. Results showed that the relationships PAR/GR generally tend to be greater during the wet periods when compared with the dry ones. By this work, it could be concluded that there is interannual variability of this relationship, showing thus, the need to consider this variability to estimate the PAR based on GR appropriately.