A method of measurement of agrotechnical spraying, in which parts of a plant covered with chemical substances, in particular agrochemicals, are analyzed by comparison with references present in a database, characterize in that UV radiation is used in excitation bands 280 nm, 300 nm, 340 nm, 400 nm and 450 nm, exposed cyclically in turn for about 10 milliseconds to perform at least 20 measurements of the spectres of excited luminescence of a sprayed plant sample, after which a plant and chemical substance are identified by comparing the obtained spectra with the references contained in a computer database, and through the analysis of the amplitude of the signals of the chemical substance, its amount on the tested plant sample is determined. The invention enables identification and quantification of the amounts of the substance when spraying cultivated plants with agrochemicals, also after the process of evaporation and after penetration of agrochemicals into plants.