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.

Brazil is responsible for 27% of the world production of soybeans and 7% of maize. Mato Grosso and Para states in Brazil are among the largest producer. The viability to the cultivation of maize (Zea mays) and soybeans (Glycine max), for future climate scenarios (2070-2100, GHG) is evaluated based on crop modeling (DSSAT) forced by observational data and regional climate simulations (HadRM3). The results demonstrated that a substantial reduction in the yield in particular for maize may be expected for the end of the 21 st century. Distinct results are found for soybeans. By applying the A2 climate changes scenario, soybean yield rises by up top 60% assuming optimum soil treatment and no water stress. However, by analyzing the inter-annual variability of crop yields for both maize and soybean, could be demonstrated larger year-to-year fluctuations under greenhouse warming conditions as compared to current conditions, leading to very low productivity by the end of the 21 st century. Therefore, these Brazilian states do not appear to be economically suitable for a future cultivation of maize and soybeans. Improved adaptation measures and soil management may however partially alleviate the negative climate change effect.

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CONSUMO HÍDRICO DA SOJA NO NORDESTE PARAENSE*  PAULO JORGE DE OLIVEIRA PONTE DE SOUZA1; SAMUEL ORTEGA-FARIAS2; EDSON JOSE PAULINO DA ROCHA3; ADRIANO MARLISOM LEAO DE SOUSA4 E EVERALDO BARREIROS DE SOUZA5 1Meteorologista, Prof. Dr. Agrometeorologia, Instituto Socioambiental e dos Recursos Hídricos, Universidade Federal Rural da Amazônia, UFRA/ISARH, paulo.jorge@ufra.edu.br2Engenheiro agrônomo, Prof. PHD. Agroclimatologia, Centro de Investigacion y transferência em Riego y agroclimatologia, Universida de Talca, UTALCA/CITRA, sortega@utalca.cl3Meteorologista, Prof. Dr. Meteorologia, Instituto de Geociências, Universidade Federal do Pará, UFPA/IG, eprocha@ufpa.br4Meteorologista, Prof. Dr. Hidrologia, Instituto Socioambiental e dos Recursos Hídricos, Universidade Federal Rural da Amazônia, UFRA/ISARH, adriano.souza@ufra.edu.br5Meteorologista, Prof. Dr. Meteorologia, Instituto de Geociências, Universidade Federal do Pará, UFPA/IG, everaldo@ufpa.br*Extraído da tese de doutorado do primeiro autor  1 RESUMO Diversas pesquisas realizadas no Brasil têm mostrado que o rendimento das culturas é influenciado por fatores climáticos, dentre eles o estresse hídrico. O consumo hídrico da soja varia com o desenvolvimento vegetal e em função das condições ambientais, com impactos relevantes em seu rendimento quando esta demanda não é atendida. Sendo assim, o objetivo deste estudo foi avaliar o consumo hídrico da soja (Glycine Max (L.) Merryl), variedade Tracajá, durante o ciclo cultural de 2007 em uma área experimental dentro de uma fazenda de produção comercial de soja no nordeste Paraense. A evapotranspiração real da cultura foi estimada pelo balanço de energia através da técnica da razão de Bowen. Os resultados permitem inferir que: i) o consumo hídrico da soja acompanhou a tendência do aumento no índice de área foliar (IAF), com máxima evapotranspiração durante o período de enchimento de grãos, cujo valor médio foi de 4,1±0,4 mm.dia-1; ii) baixos valores do fator de desacoplamento durante a fase inicial da cultura indicaram uma importante contribuição da evaporação do solo e maior controle estomático do processo; iii) com o fechamento do dossel houve uma diminuição do controle estomático indicando um aumento da contribuição da transpiração e o desacoplamento do dossel com a atmosfera, sendo a evapotranspiração controlada diretamente pela energia disponível; iv) reduções no conteúdo de água do solo durante a fase reprodutiva sugeriram um importante controle estomático na evapotranspiração da soja; v) o consumo total de água pela soja desde a fase V1 até a colheita foi de 335 mm. Palavras-chave: Fronteira agrícola, Razão de Bowen, Evapotranspiração.  SOUZA, P.J.O.P.; ORTEGA-FARIAS, S.; ROCHA, E.J.P.; SOUSA, A.M.L.; SOUZA, E.B.SOYBEAN WATER REQUIREMENT IN NORTHEAST OF PARÁ STATE   2 ABSTRACT Several studies conducted in Brazil have shown that crop yield is affected by different climatic factors, including water stress. Water consumption of soybean varies with plant development and environmental conditions, with significant impacts on its yield when this demand is not met. Water consumption of soybean crop (Glycine Max (L.) Merryl) grown during the 2007 crop cycle in a soybean production areas in the Amazon was investigated. The soybean water consumption followed the trend of increase in LAI, with maximum evapotranspiration during grain filling period, whose mean value was 4.1±0.4 mm.day-1. Low values of the decoupling factor during the initial phase of the crop indicated a considerable contribution of soil evaporation and a higher stomatal control of the process. After the canopy closure there was a decrease in stomatal control indicating an increment in the transpiration contribution besides a canopy decoupling with the atmosphere, which indicated a direct control of evapotranspiration by the available energy. Slight reductions in soil water content during the reproductive phase suggested a certain importance of stomatal control in soybean evapotranspiration. The total water consumption of soybean from the V1 stage until harvest was 335 mm. Keywords: Agricultural Border in the Amazon, Bowen Ratio, Evapotranspiration.

ABSTRACT The cowpea bean presents low productivity in the Pará state, Brazil, due to low soil fertility and climatic adversity, mainly water deficiency. The aim of this study was to evaluate the yield gap of cowpea bean in northeast of Para state in response to water deficit during its reproductive phase. The experiment was carried out in Castanhal, PA, Brazil, during 2015 and 2016. A randomized block design with six repetitions and four treatments was used; where T1 consisted of 100% replacement of the crop evapotranspiration (ETc), T2 to 50%, T3 to 25% and T4 without irrigation, in the reproductive phase. The yield was determined at R9 stage. The simulations with the SARRAZON model were carried out with different sowing dates. The total deficiencies in the reproductive phase were spatialized considering the 30 locations in order to assess the temporal and spatial seasonality of water availability and the sowing period in the study region. The cowpea bean was sensitive to soil water availability with considerable reductions in productivity due to the increase in water deficit compared to the treatment T1 (100% ETc). When water deficits reached more than 47 mm, there were yield gaps over 20%. According to the spatial variability of simulated water deficiency, the sowing of cowpea bean in regions located above 2° latitude may extend until June 20 without showing high yield gaps.

This study aims to determine the cowpea efficiency in absorbing and using solar radiation according to different irrigation depths under the climatic conditions of the northeast of Pará State. The experiment was carried out on 2014 and 2016 in an experimental design of randomized blocks, which consisted in six blocks with four treatments, in which different irrigation depths the reproductive phase were applied, as follows: T100, T50, T25 e T0, that corresponded to 100%, 50%, 25% e 0% of the crop evapotranspiration, respectively. The absorbed photosynthetically active radiation, leaf area index (LAI), total aerial dry matter (TADM) and grain yield were measured. The extinction coefficient (k) was obtained by nonlinear regression between the fraction of absorbed PAR (fPARinter) and the LAI. The radiation use efficiency (RUE) was calculated by linear regression between the TADM and the accumulated absorbed PAR. The water deficit imposed by the treatments had a significant influence on the LAI, TADM and cowpea yields. The water deficit did not significantly influenced k À it ranged between 0.83 for T100 and 0.70 for T0. The RUE showed significant behaviors regarding the treatments with adequate water supply and treatments under water deficit, ranging from 2.23 to 1.64 g·MJ -1 , respectively. ResumoObjetivou-se neste trabalho determinar a eficiência do feijão-caupi em interceptar e usar a radiação solar quando submetido a diferentes lâminas de irrigação nas condições climáticas do nordeste paraense. O experimento foi realizado em 2014 e 2016 em delineamento experimental de blocos casualizados, com seis blocos e quatro tratamentos, que consistiram diferentes laminas de irrigação na fase reprodutiva, sendo T100, T50, T25 e T 0 correspondente a 100%, 50%, 25% e 0% da evapotranspiração da cultura. Realizou-se medição da radiação fotossinteticamente ativa (PAR) interceptada, do índice de área foliar (LAI), da matéria seca total da parte aérea (TADM) e produtividade. O coeficiente de extinção (k) foi obtido através de regressão não linear entre a fPARinter e o LAI. A eficiência de uso da radiação (RUE) foi obtida pela regressão linear entre a TADM e a radiação PARinter acumulada. O déficit hídrico imposto pelos tratamentos influenciou significativamente as respostas no LAI, TADM e produtividade do feijão-caupi. O k não foi influenciado significativamente pelo déficit hídrico, apresentando variação de 0,83 no T100 e 0,70 no T 0. A RUE apresentou resposta significativa entre os tratamentos com suprimento hídrico adequado e os tratamentos sob déficit hídrico, variando de 2,23 a 1,64 g·MJ -1 , respectivamente.Palavras-chave: vigna unguiculata, radiação interceptada, coeficiente de extinção, déficit hídrico.

O presente trabalho considera as relações entre a sazonalidade climática regional e a produção de frutos de açaí representativa de 30 municípios do Estado do Pará durante um período de 9 anos (2003 a 2011). Os testes paramétricos de correlação de Pearson determinaram que o regime do período chuvoso (meses de Dezembro a Maio) associa-se a alta produtividade de frutos de açaí, enquanto que o período seco (Junho a Novembro) relaciona-se com baixa produtividade de frutos de açaí. Além disso, foram investigadas as estimativas climáticas na produção de frutos de açaí levando em conta os cenários futuros a partir dos resultados de um modelo de regressão linear tendo como variáveis preditoras: precipitação, temperatura e umidade atmosférica, fornecidos pelo modelo global HadGEM2 do IPCC (1979-2032), observou-se que a produtividade de frutos de açaí (kg/ha) tende sofrer mudanças significativas nos próximos 15 anos (2017 a 2032). Palavras-chaves: climatologia, cenários futuros, sazonalidade, regressão, Euterpe oleracea Mart. Climatic seasonal estimative over the productivity of açaí (Euterpe oleracea Mart,) at State of the Paráfuture scenarios A B S T R A C T The present work considers the relationship between the regional climatic seasonality and açaí fruits production, representative of 30 cities of Pará during a period of 9 years (2003 to 2011). The Parametric tests of Pearson correlations determined such as the regime of rainy period (months of December to May) is associated to the high productivity of açaí fruits, while the regime of dry period (June to November) relates with low productivity of açaí fruits. Moreover, it was investigated the climatic estimative on production of açaí fruits taking into account the future scenarios. Through the results of a linear regression model using as predictors variables: precipitation, temperature and humidity provided by HadGEM2 global model of IPCC (1979-2032), it is observed that the productivity of açaí fruits (kg/ha) tend to suffer significative changes in the next 15 years (2017 to 2032).

As relações entre o ENOS e a precipitação na Amazônia são analisadas num contexto espacial e temporal. Para isso, foram utilizados os dados mensais de precipitação de 238 estações distribuídas nos estados do Amazonas, Amapá, Pará e Maranhão, no período de 1920 a 2011. A identificação dos eventos de El Niño e La Niña foi feita através da análise dos campos de anomalias de precipita-ção, e foi aplicada a transformada em Ondeleta Morlet para a caracterização de todas as oscilações presentes no sinal da precipitação para o período estudado. Os resultados mostram que a distribuição espacial das anomalias positivas e negativas é bastante heterogênea, devido às interações das diferentes dimensões de tempo e escala do fenômeno ENOS e das condições de superfície da Ama-zônia. A diferença entre os eventos de El-Niño de 1982/83 e 1997/98 está relacionado à maior atua-ção em área com anomalias negativas, causando uma redução na precipitação no leste da Amazônia. Observou-se que os eventos de ENOS foram modulados por oscilações de precipitações de múlti-plas escala de tempo, tais como: decadal, interdecadal, anual e intrasazonal. Já as oscilações intrasa-zonais estiveram relacionas apenas ao evento de La-Niña 1984/85.  A B S T R A C T This study examined the relationship between ENSO and precipitation in the Amazon in a spatial and temporal. For this, we used the monthly data of precipitation of 238 stations distributed in the states of Amazonas, Amapá, Pará and Maranhão (period 1970 – 2011). For the analysis of data were made calculations of anomalies of precipitation, to identify the events of El Niño and La Niña, and application of the Wavelet Transform into Morlet to the characterization of oscillations in the sign of precipitation. The results show that the spatial distribution of positive and negative anomalies is quite heterogeneous, because the interactions of the different dimensions of time and scale of the ENSO phenomena and the surface condition of the Amazon. The difference between the events of El Niño of 1982/83 and 1997/98, be related to increased activity in an area with negative anomalies, causing a decrease in precipitation in eastern Amazonia. It was observed that the events of ENSO have been modulated by oscillations of precipitation of multiple time scale, such as decadal, interdecadal, annual and intraseasonal. It was noted also that the intraseasonal oscillations were related only to the La-Niña event in 1984/85. Keywords: Wavelets Morlet, Water Resources, extreme events.