Given the strong interactions between climate and vegetation, climate change effects on natural and agricultural ecosystems are common objects of research. Reduced water availability is predicted to take place across large regions of the globe, including Northeastern Brazil. The Caatinga, a complex tropical water‐limited ecosystem and the only exclusively Brazilian biome, prevails as the main natural forest of this region. The aim of this study was to examine the soil‐water balance for this biome under a climate‐warming scenario and with reduced rainfall. Climate change projections were assessed from regional circulation models earlier applied to the Brazilian territory. A statistical climate data generator was used to compose a synthetic weather dataset, which was later integrated into a hydrological model. Compared to simulations with current climate for the same site, under the scenario with climate change, transpiration was enhanced by 36%, and soilwater evaporation and interception were reduced by 16% and 34%, respectively. The greatest change in soil‐water components was observed for deep drainage, accounting only for 2% of the annual rainfall. Soil‐plant‐atmosphere fluxes seem to be controlled by the top layer (0.0-0.2 m), which provides 80% of the total transpiration, suggesting that the Caatinga forest may become completely soil‐water pulse dominated under scenarios of reduced water availability.

Sugarcane cultivation uses many chemical inputs to ensure good yields, which puts local water resources under pressure. Grey water footprint (GWF) is a widely used indicator of the volume needed to assimilate a pollutant load in a water body. However, the GWF relies on leaching runoff fractions, which are empirically determined. We hypothesize that these fractions might not represent the true magnitude of the Brazilian sugarcane environment and that management practices can further reduce this fraction loaded into the environment. In two field trials, we measure the herbicides and nitrate loaded into the environment through in situ measurements, determine their loss fractions, compare them with some empirical models, calculate the GWF, and estimate the potential for nitrate pollution attenuation with the adoption of split and incorporated nitrogen application. Both hypotheses are confirmed. For nitrate, our results suggest that the leaching runoff fraction used in most GWF studies is overestimated by about two times, impacting the GWF estimation for the Brazilian sugarcane environment. However, the same conclusion was not possible for herbicides due to the low diversity of the analyzed molecules. In addition, the fertilizer management application reduced the nitrate load on the environment, which the GWF did not necessarily detect.

O método do Tanque Classe A, para determinar a evapotranspiração de referência (ETo), foi desenvolvido para se ter uma forma prática para estimá-la e aplicar ao manejo da irrigação. Para a realização deste trabalho foram utilizados dados meteorológicos de uma série histórica de 15 anos, no período do ano de 1993 a 2007, da estação climatológica convencional da Universidade Federal Rural do Semi-Árido. Objetivou-se com este trabalho calcular e propor valores médios de coeficientes do Tanque Classe A (Kp) em diferentes intervalos temporais (mensal, sazonal e anual), para a região de Mossoró, Rio Grande do Norte, para auxiliar produtores rurais na sua utilização no manejo da irrigação. Os valores médios mensais do coeficiente (Kp) são os mais recomendados para utilização; a segunda escolha seria a utilização dos valores médios sazonais de 0,79 e 0,62, para período chuvoso e período seco, respectivamente; e, por último, o valor médio anual, igual a 0,71.

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