Several of the methods used to estimate actual evapotranspiration (ET a ) consider the crop evapotranspiration (ET c ) to be affected by a soil water stress co-efficient (K s ) such that ET a = K s ET c . The aim of this study was to assess the ET a estimation in maize in Alagoas State (09 ∘ 38 ′ S and 36 ∘ 40 ′ W; 260 m msl) in northeastern Brazil using the method of the single crop co-efficient from the FAO-56 paper, combined with three different approaches to determine K s . The K s was expressed as either a linear (K s,lin ) or a logarithmic (K s,log ) function of the soil water depletion. Additionally, the method proposed in the FAO-56 (K s,FAO ) was used when the impact was linear, but it was switched on after only one offset. Meteorological and soil water measurements were conducted in a maize crop from July to October 2005. The estimates of ET a were compared with the ET a determined from soil water balance. The ET a estimated with K s,lin had the highest precision (r 2 = 0.67) and accuracy (d = 0.89 and root mean square error (RMSE) = 0.67 mm d −1 ). However, the ET a determined from

RESUMOO objetivo do trabalho foi avaliar a estimativa da evapotranspiração de referência (ETo) pelo método de Penman-Monteith parametrizado no boletim FAO-56 (PM-FAO56) utilizando dados meteorológicos observados e os simulados pelo modelo atmosférico Weather Research and Forecasting (WRF). Na estimativa de ETo utilizaram-se dados meteorológicos observados (extremos da temperatura e umidade do ar, radiação solar e velocidade do vento) e simulados pelo WRF no período seco (janeiro a março e de outubro a dezembro de 2008) da região de Rio Largo -AL (9°28'02'' S, 35º49'44'' W e 127 m). As estimativas foram avaliadas pelo coeficiente de determinação (r 2 ) entre ETo obtida com os dados observados e simulados, pelo índice de concordância de Willmott (dr) e pelo erro médio absoluto (MAE). O método PM-FAO56 apresentou maior sensibilidade ao saldo de radiação, em relação aos seus termos aerodinâmicos. As estimativas de ETo apresentaram baixa precisão (r 2 = 0,41) e acurácia moderada (dr = 0,77 e MAE = 0,79 mm d -1 ). É necessário melhorar as simulações dos componentes de radiação do WRF para melhor estimar ETo pelo método de PM-FAO56 na região de Rio Largo, AL.

Phenological information contribute to silvicultural actions and conservation strategies. Here, we carried out the phenological monitoring of six tree species that were prominent in the structure of an open ombrophilous forest fragment in northeastern Brazil. Over two years, among September 2015 and August 2017, eight individuals of each species (48 trees in total) were visited every two weeks to record the reproductive and leaf phenophases, following the Fournier intensity scale. We calculated the intraspecific synchrony of the phenophases and the correlation of the phenophases of each species with meteorological variables (temperature, air precipitation and photoperiod). The species showed synchronous characteristics for the phenophases. Precipitation stood out in terms of a higher frequency of significant relationships with the reproductive phenophases. The results indicates that the end of the dry season is the most favorable period for seed collection and the monitoring of dispersers in this type of tropical forest.