MONITORING THE PHENOLOGY OF VEGETATION DEVELOPMENT BY MEASURING INDUCED FLUORESCENT EMISSION OF CHLOROPHYLL

Background. Accurate determination of phonological cycle of vegetational growth is essential for increase of effectiveness of agriculture. The issues of monitoring the phenology of vegetation development in an optimal mode are considered. The goal is to optimize the research of vegetation phenology by measuring the induced fluorescence radiation of chlorophyll. The object of the study is the phenology of vegetation development. The subject of the study is the research method for investigating the phenology of vegetation, which consists in measuring the induced fluorescent radiation of chlorophyll instead of the LAI (Leaf Area Index). Materials and methods. In the model study of the average integral value of the fluorescent radiation of the crown, solar radiation was replaced by laser radiation, which avoids the negative influence of atmospheric factors. The variational method was used to reach the formulated goal. Results. The optimization made it possible to determine the worst-case model dependence L = L(φ), where L is the distance between the lidar and the tree; φ is the quantum yield of the fluorescent signal, which leads to the smallest value of the measured average integral value of the fluorescence signal. Conclusion. It is recommended not to use such a measurement mode in the practice of monitoring plant phenology using the results of measuring the fluorescent signal of chlorophyll radiation.