SIMULATION OF THE WATER BALANCE IN A PERENNIAL GROUNDCOVER CORN INTERCROP WITH THE STICS CROP MODEL

Abstract

Increasing the provision of ecosystem services by adopting cropping systems compatible with conventional commodity agriculture is highly attractive. One such approach is to add perennial groundcover to the grain systems that dominate the working lands of the Midwest. There is the need for process-based crop models that can simulate PGC intercropping and elucidate the circumstances when PGC will compete for resources with the primary crop, reducing grain yield. The STICS model is used to simulate a corn-PGC system. The focus of this research is on competition for soil moisture between the PGC and corn. The first step is to create a plant file for Kentucky Bluegrass and to calibrate the model. Data from Zhang et al. (2013) were used to parameterize a Kentucky Bluegrass plant file and calibrate the model to measurements of annual ET, clipping biomass, percolation, and nitrate leaching. The STICS model predicted annual ET well, but less satisfactory results for clipping yield, percolation, and leaching. There were significant limitations in the model’s ability to implement management practices typical of turf grass which limited the model performance.