Using data of optic sensors and pigment content in leaves for efficient diagnostics of nitrogen nutrition

English. Received: February 23rd, 2022 ; Accepted: May 16th, 2022 ; Published: August 12th, 2022 ; Correspondence: [email protected]

English. Opportune monitoring and diagnostics of a condition of crops permit to make prompt andproper activities on dressing nitrogen fertilizers. This will allow the plants to use the nitrogen appliedefficiently, and therefore reduce their use in field. Since nitrogen that has not been utilized by plantsis able to escape into the atmosphere or be washed out of the soil with water. The most accuratediagnostic method is to determine the chemical composition of plants, but it takes quite a long timeand requires laboratory conditions, which is not always possible in the field. One of the promisingmethods is photometric diagnostics of crops using optical instruments. Experiment is carried out incontrasting weather conditions, on soddy-podzolic soil with spring barley and spring rapeseed beinginvestigated. Results of research show the efficiency of using optic sensors (N-testers) for efficientdiagnostics of nitrogen nutrition of plants. The readings of the device (N-tester) were compared withthe concentration of a and b chlorophyll, determined by a chemical method. Results of diagnosticswith portable photometric device ‘Yara’ are correlating with concentrations of chlorophylls a(r=0.96) and b (r = 0.91) in spring rapeseed. Moreover, correlation of rapeseed yield andconcentrations of chlorophylls a and b has quantity and inverse relation similar to device indication(r = -0.81 and r = -0.70 respectively). Results of diagnostics with N-tester ‘Spectroluxe’ arestrongly correlating with chlorophyll concentration. Device indication correlates stronger withchlorophyll b concentration in spring barley and chlorophyll a concentration in spring rapeseed(rapeseed was investigated in dryer conditions). Thus, such a modern optical device as N-tester,whose action is based on measuring the concentration of leafy chlorophyll, can replace chemicalmethods and increase the efficiency of nitrogen fertilization, which means increasing theproductivity of plants and reducing the negative impact of unreasonable use of nitrogen fertilizers.