<p>The agricultural distribution machine has a dosing element that supplies material, particularly crop by liquid in adjustable quantities or adjustable concentrations. A computer (2) has an electronic computing system (1) for determining the humidity degree of coverage of plants on the agricultural surfaces by a program with forecasting tool under consideration of previous or actual or predicted weather data (3). The program is stored in a storage of the computer. An expected dew coverage is calculated by the program. The calculated data is utilized for adjustment of spraying quantity.</p>