Calibration of the LINGRA-N model to simulate herbage yield of grass monocultures and permanent grassland in Slovenia | Umerjanje modela LINGRA-N za simulacijo pridelka posameznih vrst trav in trajnega travinja v Sloveniji

إنجليزي. In this study, we calibrated the LINGRA-N model using the minimization of RMSE, and proceeded to evaluate its performance. We simulated herbage dry matter yield of cock's foot (Dactylis glomerata L.) and perennial ryegrass (Lolium perenne L.) in Jablje in the period 1998–2013, and multiplespecies grassland in Ljubljana (S72) in 1974–1993. The overall performance of LINGRA-N is fair for perennial ryegrass (RMSE% < 25%) and good for cock’s foot and S72 (RMSE% < 15%). The index of agreement (d) suggests that LINGRA-N is not calibrated well enough to simulate the interannual herbage yield variability for S72, so the model cannot yet be used for the simulation of multi-species grassland herbage yield. In contrast, the herbage yields of cock’s foot and perennial ryegrass in Jablje are simulated correctly (with d values 0.84 and 0.78, respectively). One of our further goals is to use the calibrated model on a specific location for the simulation of the herbage yield of grass monocultures under various weather conditions as well as for the simulation of climate change effect on it.

السلوفينية. V raziskavi smo model LINGRA-N umerjali na podlagi minimizacije kvadratnega korena napake (RMSE) ter ocenjevali kakovost umerjenega modela. Uporabili smo podatke o pridelku suhe snovi navadne pasje trave (Dactylis glomerata L.) in trpežne ljuljke (Lolium perenne L.) v Jabljah v obdobju 1998–2013 ter trajnega travinja v Ljubljani (S72) v obdobju 1974–1993. Glede na RMSE se je izkazalo, da je bilo umerjanje primerno (RMSE% < 25 %) za trpežno ljuljko in dobro za navadno pasjo travo ter trajno travinje (RMSE% < 15 %). Vendar pa je indeks ujemanja (d) pokazal, da za S72 model ni dovolj dobro umerjen, da bi sledil medletni variabilnosti pridelka, kar pomeni, da ga v taki obliki ne moremo uporabiti za nadaljnje modeliranje pridelka trajnega travinja. Za navadno pasjo travo (d = 0,84) in trpežno ljuljko (d = 0,78) so rezultati dobri. Umerjen model bomo zato uporabili za simulacijo pridelka posamezne vrste trave pri različnih vremenskih razmerah in pod vplivom podnebnih sprememb na specifični lokaciji.