LAUSR

Data from a two-year field experiment were used to calibrate (2011) and validate (2012) the parameters required by the CropSyst model for simulating the growth of a potato crop (Agria cultivar) in a semiarid area of Spain. The primary variables analysed during the parameterization model were leaf area index, canopy cover, total dry matter, total biomass at harvest, soil moisture balance, and evapotranspiration, being the potato crop subjected to four irrigation treatments (120%, 100%, 80%, and 60% of the crop water requirements “CWR”) under a center pivot system. The results showed that the CropSyst model attained a suitable goodness of fit with regards to the simulated and observed values (Willmott’s index close to 1 and errors around ±10%). Although the model includes a reduction coefficient for taking into account the effect of both water and temperature stress on the reference harvest index, yields at harvest were not properly simulated by the model. According to the results, the calibrated and validated CropSyst model showed that the 100% and the 80% CWR treatments are the most interesting ones for the farmers in the study area (both reached a suitable rate between high yield and high efficiency in the use of water).