A calibrated model of wheat lodging compared with field measurements

This paper describes how an existing model of lodging in winter wheat (Triticum aestivum L.) has been further developed to enable it to predict the timing and amount of lodging from inputs about the crop, soil and weather. Improvements include the use of recently specified values for the drag coefficient and damping ratio of wheat shoots, accounting for temporal and spatial non-uniformity of plant characteristics, and using daily rainfall and wind run data. Stem and root lodging are predicted when the base bending moment of the shoot(s) exceed the failure moments of the stem base and anchorage system, respectively. Tests show that the model can predict the timing and quantity of lodging in crops with a wide range of lodging risks. Each area of further development contributed to the improvement of the model. Using accurate values of drag coefficient and damping ratio reduced failure wind speeds by 44% to more realistic values. Accounting for temporal non-uniformity of plants meant that the increase in lodging risk towards harvest was correctly predicted. Accounting for spatial non-uniformity enabled different sized areas of lodging to be predicted. (C) 2003 Elsevier B.V. All rights reserved.