Modeling the biomass production of the biofuel crop Miscanthus x giganteus, to understand and communicate benefits and risks in cultivation

The development of crops for biomass affords both benefits and risks to agroecosystems. Understanding these benefits and risks require tools that enable stakeholders to explore the impacts of available information and underlying assumptions on the anticipated productivity of biomass crops. A variety of abiotic (e.g., rainfall, solar radiation) and biotic (e.g., herbivorous insect pests) factors can affect crop productivity. We developed a model using the visual and user-friendly systems software STELLA, to understand the influence of abiotic factors like solar radiation, temperature and rainfall on the accumulation and loss of biomass for a biofuel crop, Miscanthus x giganteus. In addition to providing a conceptual representation of how the system may operate, the model allows performing sensitivity analysis to determine the relative impact of parameters on the estimated harvested biomass. Several site-specific or plant-specific non-climatic parameters (e.g., available soil water, solar energy interception, conversion efficiency of the plant, harvest date and evapotranspiration) significantly influenced estimates of harvested plant biomass. After validation of the model using abiotic factor inputs, an updated version incorporated biotic parameters such as potential yield losses due to herbivorous pests. Such a modeling approach can assess the different underlying assumptions of biomass production, thereby enabling stakeholders to make informed decisions on benefits and risks of growing this biofuel crop.