Diversifying crop rotations with temporary grasslands - Université de ...

(illustrated in Fig. 24). Later, remobilisation will decrease again, which might be either due to
a reduced demand (sufficient photosynthesis on newly established leaves) and/or due to a
reduced offer (depletion of the belowground resources).
Fig. 24: Daily aboveground biomass increase (ΔBMj)
before and after a partial destruction of the
photosynthetically active plant organs (cutting).
ΔBMphsynth
j, daily aboveground biomass increase powered by photosynthesis; ΔBMremob j,
daily aboveground
biomass increase powered by remobilisation of belowground carbohydrate resources. The arrow () indicates
the amount of biomass produced by photosynthesis on the residual green surface remaining after cutting.
ΔBMphsynth j depends essentially on the plant’s green surface and may be simulated by the
FLORSYS model in the same way for uncut and cut plants (based on the energy balance of
the plant estimated as a function of its light environment). In contrast, a new formula must be
developed to estimate ΔBMremob j that takes into account the considerations and experimental
ΔΒM
ΔBMj
remob j
Species 2
results discussed above:
ΔBMphsynth j
↓ Cutting
LAth
−LAj
1 ⎛
⎞
( 0;
T − T ) ⋅ ⋅⎜β
⋅ BM − ∆BM
⎟
= ⋅ ⋅
∑
⎝
j
ΒΜbefore
α max mean j b
before
LAth
1
The ‘remobilization of carbohydrates during day j’ (ΔBMremob j)
would thus depend on:
• the aboveground biomass before cutting, BMbefore
(that is correlated to belowground
biomass for a given species, Gedroc et al., 1996; Wardle et al., 2004);
174
ΔBMremob j
time
ΔBMphsynth j
remob j
⎠