Figueiredo, N.Carranca, C.Coutinho, J.Trindade, H.Pereira, J.Marques, P.de Varennes, A.2014-01-062014-01-062013Figueiredo N., Carranca C., Coutinho J., Trindade H., Pereira J., Marques P., de Varennes A., 2013. A climate change scenario and soil ammonium “fixation” during the seasonal rice (Oryza sativa) growth in Portugal under intermittent flooding. Revista de Ciências Agrárias 36 (4), 455-465.0871-018Xhttp://hdl.handle.net/10400.19/1959The “newly fixed” NH4 + in clay minerals should be considered for an efficient management of plant nutrition. In a clayloam soil cultivated in 2012 with rice under intermittent flooding and conventional agronomic practices, the dynamics of pH, N-inorganic and non-exchangeable NH4 + was evaluated i) under field conditions, air temperature and atmospheric [CO2 ] (375 µmol mol-1 air) in Salvaterra de Magos (Portugal), and ii) under elevated temperature and temperature+[CO2 ] in controlled microclimate. For that, open-top chambers were used to simulate the conditions of an increased mean air temperature (2-3 °C), alone or combined with increased [CO2 ] (550 µmol mol-1 air). Non-exchangeable NH4 was significantly higher under open-field conditions compared with the temperature elevation, with or without elevated atmospheric [CO2 ]. Temperature elevation reduced the “fixation” rate of the cation, while the CO2 concentration rise did not affect particularly the non-exchangeable form. Further studies are required for consolidation of these findings together with microbial communities and dynamics of C and N in soil.engjournal article