Impacts on light interception

The general formalization of the reduction of radiation interception by a foliar disease can be expressed as:

Where LAId is the leaf area index affected by the disease at day d (m2 m-2), LAId,dam is the leaf area index at day d (m2 m-2) and xd is the disease severity at day d. This approach has proved to be a valid system for yield loss modeling for a large number of pathosystems (e.g., Bergamin-Filho et al., 1997; Leite et al., 2006).

Most process-based crop models compute a daily value of leaf area index to derive the rate of increase of biomass production.The reduction of the daily leaf area index at day d (LAIrem,d, m2 m-2) is simulated as a function of the disease severity (Dissev,d, 0÷1) and of the leaf area index computed by the crop model in the current time step (LAId, m2 m-2).

The updated state variable of the leaf area index (LAId*, m2 m-2) is then computed as in the following equation and provided as input to the crop model at the next time step.

As an example, the Figure below shows the impact of the reduction of leaf area index in a dynamic simulation in which blast-rice epidemic development is simulated by the DiseaseProgress component and rice crop growth and development is simulated by the WARM model(Confalonieri et al., 2009):

Reduction of leaf area evolution simulated by the ImpactsOnPlants component.

Created with the Personal Edition of HelpNDoc: Create iPhone web-based documentation