Improving crop representation in an ecohydrological model: a proof of concept

Agricultural crops represent some 10% of the Earth’s land surface and their sustainable management is key to maintain ecosystem services and ensure food security. Arguably, the first step towards successful management of these croplands is a detailed understanding of their intricate energy,water,carbon and nutrient dynamics. This is best achieved via mechanistic ecohydrological modeling which facilitates the study of explicit processes such as crop growth and nutrient leaching. For example, this method allows us to investigate soil biogeochemical cycling under different fertilization practices which would otherwise be challenging using an alternative empirical modelling approach. 

In this proof of concept study, we expand the T&C ecohydrological model to represent agricultural crops and the associated soil biogeochemical dynamics. This is accomplished via the introduction of a new model component which represents individual crop dynamics. Specifically, we develop new algorithms to represent crop-specific phenology, crop-specific carbon allocation schemes,  as well as crop-specific management practices which span from sowing to fertilization to harvest. We apply T&C-crop to three agricultural catchments in the UK. Model validation is performed for several crop types in terms of leaf area dynamics, crop yield, hydrological dynamics and downstream nitrogen release.