Determination of nitrogen and chlorophyll content in two varieties of winter wheat plants means of ground and airborne spectrometry

Abstract

Nitrogen in plants is part of the green pigment chlorophyll, as well as proteins, nucleic acids, phytohormones and alkaloids that indicates the key role of this element in plant life. Chlorophyll is the most important pigment of the photosynthetic process determining the life of all heterotrophic organisms on the planet. The facts mentioned above presuppose close relationships between nitrogen and chlorophyll in plants. The nitrogen content in plants serves as a basis for adjusting their nitrogen nutrition and calculating fertilization rates for high yields. This causes comstant importance of studying the content of nitrogen and chlorophyll in plants, especially by means of novel techniques with involving remote sensing. This study was focused on relationship between 19 vegetation indices (VI) and biochemical characteristics of vegetation, in particular nitrogen and chlorophyll content. Study areas were located within production fields of two varieties of winter wheat grown for harvest in 2016 by the grain company Baryshivska. The test plots varied by phytopathological situation in the phase of milk ripeness. Fungal infection of Bogdana variety caused significant varietal differences in biochemical parameters that were calculated by Kjeldahl makro-method for total nitrogen and by aerial survey with UAV (drone) for chlorophyll content. Among 19 VIs calculated by ground spectrometry the major part (16 VIs) were consistent with changes in nitrogen and chlorophyll content in the cultivars. In particular, CI rededge , CI green , MTCI, RVI, D731 / D700 and D735 / D700 were more than doubled, and NDRE1 and D718 / D700 were almost 1.5 times higher in the Skagen variety compared to the Bogdan variety. Only 3 indices: NDVI, Green NDVI and NI had limits of fluctuations of the values within the same limits, as varietal differences of biochemical indicators.