A MODEL FOR THE DRYING OF GRASS WITH REALTIME WEATHER DATA

A model for the drying of grass is presented which uses weather elements measured by standard weather stations. The model is based on that of Brück and Van Elderen which is transformed into the present predictive model and uses the air temperature and dew point temperature, both at screen height, the wind speed at 10 m height, quantity of rain, the global radiation and the cloud cover. The decrease and increase of free and absorbed water in the grass is calculated. All weather elements are taken hourly, except the quantity of rain which is taken every 6 h. The drying process of the model is described and results are presented for two drying events. Favourable agreement was found between predicted and measured moisture contents of the grass in the field. The error in the calculated moisture content of grass at a stated time was at most 3% wb. Alternatively, the error in the time to reach a given moisture content was at most 2 h. © 1992 Silsoe Research Institute.