1. Introduction to plant modelling

2. Phenology Most important stages: Sowing, Flowering & Maturity. Each phase develops through cumulative thermal time, can include photoperiod & vernalisation responses.

3. Photosynthesis Potential Growth= f(cover, radiation, rue) ∆DM = RUE x radn x cover RUE = f(water, N, P, T, CO 2 ) cover = 1 - e -k x LAI (Beer-Lambert law) RUE – radiation use efficiency. (grams biomass / MJ) K – extinction coefficient; crop specific, affected by row spacing. Water limited growth = sw supply * TE C / VPD TE C = Transpiration efficiency coefficient. Actual growth = minimum of potential and water limited growth.

4. Biomass production Partitioning to leaf, stem, ear/pod and root is stage dependant. Grain filling takes priority during reproductive growth. Sink size is determined by one of Harvest Index, Grain number/size Grain cohorts (ears).

5. Stress affects different processes in different ways SW: Reduced availability slows dm production FX photosynthesis & phenology via supply:demand ratio FX leaf-expansion & nitrogen fixation via fr_asw N Reduction of RUE Grain N content Phenological development Frost, Age Leaf senescence

6. N fixation ‘Magic’ supply of N to maintain concentration in all plant organs Extra N in the system comes from roots & surface residues that are returned at maturity

7. Root development Constant (~20mm/day) in wet soil layers, slows down as layer dries Can be further delayed by XF

8. Why does my crop die? Look in the summary file: Was it ever sown? At the right time? Did it get a reasonable peak LAI? Did it encounter stress?

9. Why does my crop die? Look in the summary file: Was it ever sown? At the right time? Did it get a reasonable peak LAI? Did it encounter stress?

10. Why does my crop die? Look in the summary file: Was it ever sown? At the right time? Did it get a reasonable peak LAI? Did it encounter stress?