Comparison between hydrological submodels in EPIC and CropSyst simulation models

摘要

Crop simulation models consist of several sub-models interacting with each other to give a final output. In arid and semi-arid environments of Southern Italy, water availability limits and conditions the yields of many herbaceous crops. The water balance sub-models of two simulation models, EPIC and CropSyst, were compared. The two models use a cascade system, with a direct storage in the upper layer until water content equalizes field capacity, then excess cascades to succeeding layers. CropSyst provides also another option, with the numeric solution of Richard's equation (finite difference). Experimental data were obtained in a comparison of 4 water regimes in sunflower, carried out at Foggia, Italy, in 1996 and 1997. Observed and simulated values showed a good comparison for yield, seasonal water use and soil water content. Between the models the importance in EPIC of leaf area index driving biomass accumulation, water uptake and evaporation was observed, while in CropSyst, soil and plant water potentials appeared fundamental. CropSyst also had the capability to simulate soil water content below wilting point, according to experimental data due to the cracking phenomena.