A model of asparagus growth physiology

This paper describes a model that simulates events during the annual cycle of asparagus (Asparagus officinalis L.), and uses daily radiation and temperature to predict potential growth and yield. It simulates key growth and development processes each day for an average plant in a mature crop, and uses the plant population to convert to a unit area basis. Processes simulated include spear and fern growth, which utilise resources from the crop's storage root system (soluble carbohydrate (CHO) and buds), and assimilation by established fern, which replenishes the resources. These processes are regulated by temperature during the dormant and spear harvest phases of the annual cycle, and also by solar radiation during the fern growth and assimilation phases. Differences among cultivars are defined by their responses to temperature and partitioning of resources within the plant. The results from the simulations are used to update daily the status of the plant in terms of the state variables which are the biomass and CHO content of the root system and the number of buds on the crown. Thus, over time, the model simulates patterns of spear growth, fern growth, and accumulation and depletion of CHO and buds. The model is useful for investigating the effects of varying climatic and management factors that influence crop performance. For example, it can be used to examine the effects on spear yield, fern growth and root system resources of different temperatures, size of root system, spear harvest duration, or harvesting spears at different times during the annual growth cycle. Therefore, it has the potential to be a useful tool for supporting management decisions to optimise crop performance, both in the current season and in following years.