On the basis of economical importance of mass determination of material streams, especially in agriculture, the radiometric measuring principle was proved as the priority solution for estimation of the transported masses. Optimal arrangements of sources and detectors with a minimum influence of material cross distribution on the weighing processes were found by theoretical and experimental studies. This radiometric conveying mass gauge was subjected to a serial of tests under research and agricultural conditions. The influence of various factors (e.g. moisture content, crude ash content, kind of agricultural material) was studied.