Development of a simulation model for sugar beet growth under water and nitrogen deficiency

Sustainable and profitable production of sugar beet requires information on knowing the effect of applied water and nitrogen (N), which is typically provided by simulation models. Considering limited information, it is essential to develop simulation models that can address irrigation water and N deficiencies for sugar beet production. The sugar beet simulation model (SSM) was developed for the simulation of storage root dry matter, plant-top dry matter, and the yield of white sugar under different applied N fertilizer and irrigation. The SSM simulates water, N, and soil heat flux under unsteady state conditions by applying numerical analysis in the root zone. Dry matter production and partitioning into plant top and root dry matter for different plant growth stages were simulated based on intercepted solar radiation, air temperature, and the amounts of N uptake. 2 years of field experiments data (2013 and 2014) were used to conduct model calibration and validation, respectively. In 2013, irrigation treatments were 130, 100, 85, 75, 66, and 44 percent of full irrigation, and N treatments were 0, 60, 120, and 180 kg N ha(-1) in the form of urea under line source sprinkler irrigation system. In 2014, irrigation treatments were 120, 100, 80, and 60 percent of full irrigation and N treatments were 0, 60, 120, 180, and 240 kg N ha(-1) in the form of urea under furrow irrigation system. Dry matter production was simulated according to radiation use efficiency (RUE) and was calibrated using the plant top and storage root dry matter production of treatment without water and N deficiency, which was 0.97 (g MJ(-1)). The normalized root mean squared error (NRMSE) criterion was used to compare the simulation capability of the model with measured field data. White sugar yield, plant leaf area index, plant top dry matter, and storage root dry matter at harvest time and during the growing season showed acceptable NRMSE values. The values of the produced white sugar yield were simulated with NRMSE of 7.8% and 14.2% in calibration and validation data, respectively. The new and relevant information provided by the SSM was quite significant as it proved that possibility of management sugar beet under irrigation water and N deficiencies.

Automated summary

The development of the sugar beet simulation model (SSM) is crucial for addressing irrigation water and nitrogen deficiencies in sugar beet production. The model simulates dry matter production and partitioning under different growth stages by applying numerical analysis in the root zone, providing valuable information for managing sugar beet under irrigation water and nitrogen deficiencies.