Radiation use efficiency response function at grain filling

The reduction of radiation use efficiency due to grain filling. In this case the maximum reduction, ε_Lred , is put to 50% and the original, unreduced radiation use efficiency, ε_L, is 2.3 gDW/MJ. At the start of the grain filling there is no reduction of the radiation use efficiency, but during grain development the reduction increases linearly until the end of grain filling where the reduction has reached its maximum value.