A simulation model of the wheat crop in response to water and nitrogen supply: II. Model validation

Abstract

The simulation model of soil water, mineral nitrogen supply and crop response of the wheat crop described in Part I was validated against field data from two semi-arid sites in northwest Victoria, Australia, over a period of 4 yr. The experimental data consisted of the four fallow combinations of stubble retention and zero tillage plus a tilled summer fallow prior to pea and wheat crops in rotation. Total soil water was simulated well (R2 = 0.95; RMSE = 0.02 Mg/m3) with a generally good characterization of the soil water profile. Some under-estimation of water content occurred at depth during the final crop growth stage as a consequence of over-estimation of crop growth and water use. Total ..