Ecological niche models (ENMs) can be used to investigate the shifts in geographical distributions and in productivity of cultivated species in future climatic scenarios. Such models can be classified in correlative, mechanistic or hybrid. The aim of this study was to investigate the relationship between productivity of Zea mays in Brazilian municipalities and crop suitability in current scenarios using the three different ENMs' types, as well as to predict the impacts of climate change on the geographic distribution of Z. mays in Brazil The mechanistic model used was Plantgro, the correlative one was Maxent, and to hybridize them we added the mechanistic model output as another predictor in a second Maxent model. The correlative and hybrid models were very similar, while the mechanistic model presented very distinct results from the other two models. The correlative (maxent) model was the best surrogate of maize productivity. The correlative model indicated that in the future there will be little change in environmental suitability in relation to the current climate.

The impacts of global climate change have been a worldwide concern for several research areas, including those dealing with resources essential to human well being, such as agriculture, which directly impact economic activities and food security. Here we evaluate the relative effect of climate (as indicated by the Ecological Niche Model-ENM) and agricultural technology on actual soybean productivity in Brazilian municipalities and estimate the future geographic distribution of soybeans using a novel statistical approach allowing the evaluation of partial coefficients in a non-stationary (Geographically Weighted Regression; GWR) model. We found that technology was more important than climate in explaining soybean productivity in Brazil. However, some municipalities are more dependent on environmental suitability (mainly in Southern Brazil). The future environmental suitability for soybean cultivation tends to decrease by up 50% in the central region of Brazil. Meanwhile, southern-most Brazil will have more favourable conditions, with an increase of ca. 25% in environmental suitability. Considering that opening new areas for cultivation can degrade environmental quality, we suggest that, in the face of climate change impacts on soybean cultivation, the Brazilian government and producers must invest in breeding programmes and more general ecosystem-based strategies for adaptation to climate change, including the development of varieties tolerant to climate stress, and strategies to increase productivity and reduce costs (social and environmental).

RESUMOModels that estimate potential and depleted crop yield according to climatic variable enable the crop planning and production quantification for a specific region. Therefore, the objective of this study was to compare methods to sugarcane yield estimates grown in the climatic condition in the central part of Goiás, Brazil. So, Agroecological Zone Method (ZAE) and the model proposed by Scarpari (S) were correlated with real data of sugarcane yield from an experimental area, located in Santo Antônio de Goiás, state of Goiás, Brazil. Data yield refer to the crops of 2008/2009 (sugarcane plant), 2009/2010, 2010/2011 and 2011/2012 (ratoon sugarcane). Yield rates were calculated as a function of atmospheric water demand and water deficit in the area under study. Real and estimated yields were adjusted in function of productivity loss due to cutting stage of sugarcane, using an average reduction in productivity observed in the experimental area and the average reduction in the state of Goiás. The results indicated that the ZAE method, considering the water deficit, displayed good yield estimates for cane-plant (d > 0.90). Water deficit decreased the yield rates (r = -0.8636; α = 0.05) while the thermal sum increased that rate for all evaluated harvests (r > 0.68; α = 0.05). Estimativa da produtividade agrícola da cana-de-açúcar para as condições climáticas do Centro GoianoModelos que estimam a produtividade potencial e deplecionada dos cultivos agrícolas em função de variáveis climáticas tornam possível o planejamento agrícola da lavoura e a quantificação da produção para uma dada região. Sendo assim, objetivou-se comparar métodos para a estimativa da produtividade da cana-de-açúcar cultivada nas condições climáticas da região central do Estado de Goiás. Para isto, utilizaram-se o Método da Zona Agroecológica (ZAE) e o modelo proposto por Scarpari (S), correlacionando-os aos dados reais de produtividade da cana, em uma área experimental, localizada em Santo Antônio de Goiás GO. Os dados de produtividade são referentes aos anos safra 2008/2009 (cana-planta), 2009/2010, 2010/2011 e 2011/2012 (canas-soca). Foram avaliadas também as taxas de produtividade em função da demanda hídrica atmosférica e do déficit hídrico da região de estudo. As produtividades estimadas e reais foram ajustadas em função da quebra de produtividade devido ao estádio de corte da cana, utilizando-se a redução de produtividade média observada na área experimental e a redução média para o estado de Goiás. Os resultados indicaram que a metodologia ZAE considerando o déficit hídrico apresentou boas estimativas de produtividade para a cana-planta (d > 0,90). O déficit hídrico ocasiona redução na taxa de produtividade (r = 0,8636, α = 0,05), enquanto a soma térmica contribui para o aumento dessa taxa em todas as safras avaliadas (r > 0,68, α = 0,05).Palavras-chave: Saccharum spp.; planejamento agrícola; modelo de previsão de produtividade.

The remote sensing and Geographic Information Systems (GIS) development have encouraged and improved the use and spansion of hydrological models worldwide. This development allows the use of hydrological models, simulating watersheds systems operation in a more simple, economical and realistic way. In order to maximize this integration, new computational tools, hydrological models and GIS are being developed. This study aimed to apply the scientometric study to quantify and verify the tendencies of the scientific publications of hydrological models and their integration with geographic information systems (GIS). Scientific papers search was accomplished in Scopus database, using the following terms: modeling OR model* AND hydrologic* OR hidrological AND “Geographic* Information* System*” OR “GIS”, and the data were obtained on September 21, 2015. It can be observed, in general, an increase in the number of papers published according to time, in years (r = 0.96) and the same trend was observed for Brazilian studies, starting from 2006. Moreover, the main direction of these studies is to develop methodologies that could integrate hydrological models with GIS.

Este trabalho visa caracterizar a cinética de secagem de feijão carioca, cultivar BRS Estilo e Canadense e ajustar diferentes modelos matemáticos. O produto foi submetido à secagem em estufa nas temperaturas de 35, 55 e 65 ºC. Amostras foram colocadas em bandejas de metal com fundo telado, em três repetições. Durante o processo de secagem, as bandejas com as amostras foram pesadas periodicamente, até que atingisse a massa constante. Os modelos matemáticos foram ajustados aos dados utilizando o software Statistica 12.0, e os parâmetros para selecionar o melhor modelo foram: o coeficiente de determinação ajustado, o erro médio relativo e o erro médio estimado.

The estimate of the potential sugarcane productivity through agroclimatic models aids in the agricultural planning of the crops and the quantification of the yield for a given region. For these estimated values to be considered robust there is a need for validating the performance of such models in different areas and agricultural varieties. Hence, the aim of this study was to validate the Agro-Ecological Zone (AEZ) method with fifteen sugarcane varieties in the region of the Vale do São Patrício, state of Goiás, Brazil. We evaluated the data referring to the cane-plant (one-and-a-half-year sugarcane), as well as the first and second sugarcane ratoons (both with one-year cycles) in an irrigated and dry farming system. The productivities obtained in dry farming were corrected due to the occurrence of a water deficit in the crop. The results indicated that the AEZ method presented productivity estimates more satisfactory for the one-year cultivation cycles (ratoon cycles) for all varieties studied, with the model adjusting best to the CTC15 variety (RMSE = 8.70 t ha-1 ; MAE = 6.05 t ha-1 ; d = 0.99).

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RESUMO: Objetivou-se determinar a quebra de produtividade de um canavial em função do déficit hídrico e do número de cortes. A área de estudo localizava-se em Santo Antônio de Goiás-GO, na usina CentroÁlcool, onde foram coletados dados de produtividade das safras de 2008/2009 a 2011/2012. Além disto, foram obtidos dados médios de produtividade para o estado de Goiás, no site da Conab. As quebras de produtividades foram estimadas a partir da relação entre a safra em questão e a safra de maior produtividade (cana-planta). Para determinar o déficit hídrico foi realizado o balanço hídrico sequencial mensal, para a cana. Verificou-se que a quebra de produtividade do canavial foi mais influenciada pelo número de cortes (r = 0,8028; α = 0,05), aumentando de forma linear em função do número de cortes. A mesma tendência foi observada para os dados médios do estado de Goiás (r = 0,9718; α = 0,05). O déficit hídrico não mostrou correlação positiva com as quebras de produtividade (r =-0,9970; α = 0,05), pois o período de déficit ocorreu, em todas as safras, no estádio de maturação da cultura, onde há necessidade de um período de déficit moderado para o acúmulo de sacarose, e não nos estádios de crescimento vegetativo da cultura.