A generic model to simulate the growth of forage legumes with contrasting architectures

Faverjon, Lucas; Louarn, Gaëtan

A generic model to simulate the growth of forage legumes with contrasting architectures

2016

Faverjon, Lucas | Louarn, Gaëtan

Predicting the yield and botanical composition of multi-species grasslands remains a challenge, mainly because of the complex feedback loops of competition for resources taking place between plants above-and belowground. Individual-based models of plant communities are promising to help disentangle these interactions. In the present study, we present and evaluate a plant model dealing with the 3D morphogenesis, growth and N acquisition of forage legumes. The model was developed to account for herbaceous legume species regardless of their growth habits above-and belowground. The model was calibrated for six contrasting species on the basis of a series of greenhouse experiments. An independent outdoor experiment was carried out to assess model outputs under non-limiting water conditions. We confirmed that the generic set of production rules used in the model was able to capture the diversity of morphogenetic strategies encountered among forage legumes. Model predictions were accurate for shoot organogenesis, leaf area expansion, plant height, rooting depth and root density distribution for isolated plants of the different species. The contrasting responses of plant species to a defoliation event were correctly anticipated. However discrepancies were observed with respect to dry matter accumulation in one of the species, due to inaccurate representations of leaf area distribution and intercepted radiation. Further model evaluations are required concerning the responses induced by competition for resources in dense stands.

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