Fig. 1.

Fraction of transpirable soil water (FTSW) versus days after emergence at Avignon (AV; solid line), Clermont-Ferrand (CF; dashed line), and Rothamsted (RR; dash-dotted line) simulated with the wheat simulation model SiriusQuality2 under high N supply. Lines are median values for each site calculated for 40 years (1970–2009). Box plots show the interannual variability of FTSW calculated over the same period and plotted every 30 d (for the sake of clarity), the edges of the boxes represent the 25% and 75% percentiles, and the solid vertical bars the 10% and 90% percentiles. Filled diamonds and circles indicate the median of the beginning of stem extension (Zadoks stage GS31) and of the anthesis date (GS65), respectively. The horizontal dashed lines indicate the default values in SiriusQuality2 of the FTSW threshold for the responses of leaf expansion (UpperFTSWexp=0.65), leaf senescence and stomatal conductance (UpperFTSWgs and UpperFTSWsen=0.5), and biomass production (UpperFTSWrue=0.3). Simulations were performed using the default value of all the parameters (Table 1). (This figure is available in colour at JXB online.)