DETERMINATION OF THE QUALITY OF FORECAST MOISTURE-CONTENT OF CEREALS AT HARVESTING TIME USING FORECAST WEATHER ELEMENTS

The moisture content of wheat and barley is forecast during the harves ting period. Each hour the forecast model uses standard weather elemen ts of air temperature, dew-point temperature, wind speed, amount of pr ecipitation, global radiation and cloud cover. Over a period of four y ears, 1989-1992 inclusive, a five-day weather forecast is made every d ay for one month during the harvesting period. The forecasts were comp ared with those made using realized weather elements in this period. F orecasting the moisture content of wheat and barley up to three days a head gives a better prediction of moisture content than with a longer forecasting period. Mean deviation in forecasting the moisture content of wheat and barley is at most 1.1 and 1.2% w.b. On average, barley h as a greater deviation in the forecast moisture content than wheat. Hi gh moisture contents of the grains (about 25% w.b.) can be caused by l ow air temperature, low global radiation, high dew-point temperature, high wind speed, and precipitation. The low moisture content of cereal s (10-30% w.b.) compared with cut grass destined for ensiling (50-85% w.b.) denotes that dew point temperature and wind speed are also impor tant. (C) 1998 Silsoe Research Institute.