Simulating Potato Growth and Nitrogen Uptake in Eastern Canada with the STICS Model

Abstract

The ability of process‐based soil–crop models to simulate potato (Solanum tuberosum L.) yield and N uptake for a range of N fertilization under the conditions of eastern Canada has never been tested. Our objectives were (i) to calibrate and evaluate the performance of the STICS model for the Shepody and Russet Burbank cultivars with cultivar‐specific critical N concentration dilution curves, and (ii) to quantify the gain in model performance with cultivar‐specific N concentration curves rather than a generic curve. Data sets including measurements of leaf area index (LAI), total and tuber biomass, and total and tuber N uptake for several N rates (0–280 kg N ha−1) collected at Charlottetown, PE; Fredericton, NB; and Québec, QC, Canada were used. Calibration was done with one data set from Charlottetown for Shepody and one data set from Québec for Russet Burbank, while all the other data sets were used to evaluate model performance. Following calibration, the STICS model generally performed well, with a normalized root mean square error (NRMSE) < 30% and a normalized mean error (NME) ranging from –8% to 23%, for LAI and biomass. Model performance was slightly worse for total and tuber N uptake, although cultivar‐specific N concentration curves for Shepody and Russet Burbank improved model performance compared with a generic curve with a lower NRMSE (18–50% vs. 21–63%) and NME (–9 to 23% vs. –14 to 23%). Cultivar‐specific critical N concentration curves should therefore be used for assessing the N budget of potato cropping systems.Core Ideas The STICS soil–crop model was calibrated and evaluated for two potato cultivars. Calibrated and evaluated variables were LAI, total and tuber biomass, and total and tuber N uptake. Cultivar‐specific critical N concentration curves are recommended for N budget assessment.

STICS Soil–Crop Model Performance for Predicting Biomass and Nitrogen Status of Spring Barley Cropped for 31 Years in a Gleysolic Soil from Northeastern Quebec (Canada)

“…The normalized mean error (NME) (Equation ( 2)) estimates the model's relative bias. An |NME| < 10% is considered a low bias [40,62]. The normalized root mean square error (NRMSE) (Equation ( 3)) is used to determine the error of prediction of the model by giving more weight to larger errors and it represents the relative mean deviation of the predicted values to the observed values.…”

“…The verification of LAI dynamics which plays a key role in predicting plant biomass accumulation and the validation of the critical N dilution curve parameters for spring barley may also be required to predict AGB and NU more precisely. Morissette et al [40] concluded that using cultivar-specific N dilution curves instead of the default curve improves STICS performance and is essential for adequately predicting the N cycle of potato growing systems. To our knowledge, no critical N dilution curve for spring barley grown in agricultural soils from the six provinces of eastern Canada (New Brunswick, Newfoundland, Nova Scotia, Prince Edward Island, Quebec, and Ontario) has been established or at least validated to date.…”

“…The integration of a snow-cover module has extended the possibility of using STICS for cold and humid continental regions [38]. STICS has also been calibrated and evaluated for non-consecutive simulations with annual resetting under these conditions for maize [39], potato (Solanum tuberosum L.) [40], and timothy (Phleum pratense L.) [41].…”

Modelling potato growth

“…First, a general crop model can be made more specific by adjusting its parameters for different crops or cultivars (e.g. Morissette et al, 2016). It should be noted that this kind of procedure does not necessarily compromise the realism of the model.…”

“…Other applications of mechanistic potato models have been recently used in strategic planning, for testing different management options, and for scenario analysis. Morissette et al (2016) used the STICS model for the Shepody and Russet Burbank potato cultivars to generate cultivar-specific Critical Nitrogen Concentration Curves in eastern Canada. Borus et al (2016) used the new APSIMpotato model to simulate the effects of N-fertilizer levels, sowing dates, plant density and irrigation treatments, and tested the model in highly different climatic conditions (Tasmania and Kenya).…”