Variability of potential and water-limited sugar beet and spring wheat yields simulated with WOFOST model.

摘要

Potential and water-limited yields of spring wheat and sugarbeet in 1961-93 were simulated with crop growth model WOFOST 6.0 [See Diepen, C. A. van; Wolf, J.; Keulen, H. van; Rappoldt, C. Soil Use Management (1989) 5, 16-24] for the Prague region, Czech Republic. Monthly averages of weather data and daily precipitation were used as driving variables. The study was aimed at the estimation of the combined effects of soil water reserves at seedling emergence (water available capacity - WAC) and of precipitation during the growing season on seasonal yield variability. The results were compared with the variability of potential yields and with average national yields. Seasonal variation in sugarbeet yields was lowest under non-limiting conditions (9.3%). Decreasing soil water at emergence from 20 cm of water available capacity (20 WAC) to 10 cm (10 WAC) increased yield variability from 15.3% to 30.5%. Simulated potential sugarbeet root yields reached 16.0 t/ha and decreased to 12.0 t with decreasing water availability. Yield variability in wheat increased from 5.8% under potential, non-limiting conditions, to 13.0% and 32.3% at 20 WAC and 10 WAC, respectively. Average [grain] yields decreased from 8.4 t/ha to 6.2 t.