The risk of yield losses due to crop diseases will increase in a cropping system without chemical-synthetic crop protection. Weather conditions and the resultant micro-climate within the canopy control the appearance and subsequent spreading of pathogens (Vidal et al., 2017), which is particularly significant for fungi-induced crop diseases.

Certain aerodynamic properties (displacement height, roughness length etc.) determine how much the canopy heats up or time is needed to dry off after a rain event. These properties depend on seeding density, seeding geometry, leaf area, leaf width, leaf inclination or the variability of crop height (Goudriaan, 1989). The fundamental equations of viscous motion, can be solved in 3D simulations using “computational fluid dynamics” (CFD). Over the last years this well-established tool has been applied in innovative ways to optimize agricultural production.

The central working hypothesis of this project is that the fungi-induced infection risk, however, can be reduced by optimizing the micro-climate (e.g., by equidistant row spacing).

In this case, the canopy’s aerodynamic is regarded as the decisive factor, whereupon the core issue is to improve the turbulent mixing of the upper canopy layers. This project will introduce 3D CFD to investigate the fine structure of turbulent mixing at the canopy-atmosphere boundary layer. A virtual wind tunnel will be set up to investigate the effect of canopy- and plant architecture on turbulent mixing.

A virtual wind tunnel will be set up to investigate the effect of canopy- and plant architecture on turbulent mixing. The results will be transferred to the crop growth and land surface model NoahMP-Gecros (Ingwersen et al., 2017) to simulate temperature and humidity dynamics in the canopy and to assess the infection risk. The new insights, gained from the virtual wind tunnel simulations, will establish new recommendations for breeders and field management in NOcsPS cropping systems.

Micro-climate measurements are intended to show that equidistant row spacing allows for a better gas exchange of canopies than normal drilling. The 3D flow simulations confirm the measurement results and give detailed, quantitative insights into the turbulent exchange processes within canopies. Based on combined 3D flow and NoahMP-Gecros simulations, the fungal infection risk can further be reduced, in excess to equidistant row spacing, by optimizing crop and canopy architectures.