A preliminary evaluation of the simulation model CropSyst for Alfalfa.

2004 - European Journal of Agronomy, 21, 223-237
Confalonieri, R., Bechini, L.


This work stems from the need to set-up appropriate simulation models for scenario analysis of intensive forage cropping systems in northern Italy, where alfalfa plays a major role. CropSyst is a deterministic, process-based, with daily time-step cropping systems simulation model. It can simulate crop growth and development, water and nitrogen balance for herbaceous annual and perennial crops. In thiswork, itwas used to simulate aboveground biomass (AGB) accumulation and soilwater content (SWC) for two alfalfa meadows seeded in 1996 and 1997 in Lodi, northern Italy (45◦N latitude). The crop was parameterised with data from the literature, local experience and calibration with measured data from the first 2 years. Data from the third year were used for validation.
The cumulative yields of the 3-year periods were 38.2 and 36.9 tAGBha−1, obtained with a total of 14 cuts. The set of crop parameters is consistent with values reported in the literature. For most of the cuts, the model simulates appropriately the growth of the crop: the relative root mean squared error (RRMSE) between observed and measured AGB ranged between 3 and 6% after calibration and between 3 and 5% after validation. RRMSE for SWC ranged between 13 and 21% after calibration and between 10 and 20% after validation. Even if some limitations are explicitly addressed, this crop parameter set can be already used for explorative scenario simulations in the study area. This work has demonstrated the robustness of the model for perennial forage crops simulations and has suggested some improvements of the model (automatic scheduling of cuts, role of crown reserves).

Keywords: Alfalfa; simulation model; forage crops; growth and development; northern Italy; soil water content
DOI: 10.1016/j.eja.2003.08.003