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

• a remobilisation coefficient, α, determining the potential rate of remobilisation per day (α
varies according to weed species, the number and frequency of times the plant has
previously been cut and the plant age or phenological stage, such as illustrated in Fig. 24);
• the temperature interval between mean temperature at day j, Tmean j and the base
temperature of plant growth specific of each species, Tb;
determining the speed of
biochemical processes including remobilisation
• a coefficient reducing the remobilisation rate when the actual leaf area, LAj-1,
converges
during regrowth to a threshold leaf area, LAth that determines the point where plant
growth and respiration may entirely be powered by photosynthesis. (As this threshold is
actually not known, it may be assumed for simplicity that it is equal to the known leaf area
might be lower, but the model will
before cutting: LAth = LAbefore ; in reality, LAth
probably not be very sensitive to this parameter).
• The differences between the sum of biomass remobilized from cutting until day j,
∑ΔBMremob
j, and the total quantity of remobilizable carbohydrates, which is determined
by the biomass before cutting, BMbefore,
and β, a coefficient determining the total part of
biomass that may potentially be remobilized.
Therefore, remobilisation will decline and fade out when the available reserves are depleted or
when enough new leaf area is established. The proposed formalism for simulating post-cutting
regrowth is basically a model with 2 unknown parameters, α and β (Tb is already known in
the FLORSYS model and LAth might be assumed to equal LAbefore).
Both parameters, α and
β, would vary according to weed species, the number of times and the frequency the plant has
previously been cut and the plant age or phenological stage, and might be estimated from the
data obtained in the greenhouse experiments (chapter C.III). After implementing the model, an
analysis of the model sensitivity to these parameters will have to be performed. It seems likely
that the model will be highly sensitive to α determining the remobilisation rate immediately
after cutting.
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