Koti, R.V.Spandana, K.S.2024-07-202024-07-202018-06https://krishikosh.egranth.ac.in/handle/1/5810212296A field experiment was conducted during kharif, 2017 at the Main Agricultural Research Station, University of Agricultural Sciences, Dharwad to study plant sap analysis for enhancing the physiological nitrogen (N) use efficiency in maize. N levels at 100, 50, 25 and 0 kg ha-1 including three other treatments on plant demand viz., 50 % recommended N + rest through soil application, 0 N + rest by soil application and 0 N + foliar application, based on tissue nitrate tests by nitrate ion meter were tried in simple randomized block design with four replications. The results revealed that soil application of N at 100 kg ha-1 at sowing showed significantly higher sap nitrate (1037, 660 and 502 ppm at 30, 55 and 70 days after sowing respectively) and other sap indices, total leaf nitrogen (2.25 %), plant height (230.6 cm), relative chlorophyll content (57 SPAD value), plant performance (13,167), total chlorophyll (3.34 mg g fresh weight-1), leaf area (79.8 dm2), total dry matter (399.7 g plant-1), grain weight per cob (246.7 g), grain yield (106.9 q ha-1), stover yield (100.1 q ha-1) and nitrogen use efficiency (NUE) of grain and dry matter (35.79 and 30.83 respectively) which are on par with 50 % recommended N at sowing + rest by soil application based on sap nitrate test i.e on demand. Higher gross returns ( . 1, 22,577), net returns ( . 90,198) and B: C ratio (2.79) was observed with application of 100 % recommended N which is on par with 50 % recommended N + rest by soil application based on tissue nitrate test. It is inferred that nitrate ion meter can be used for quantification of nitrogen requirement based on crop demand with saving of 30 per cent nitrogen and avoiding environment pollution. Thus, technology is farmer’s friendly and enhances the NUE.EnglishThesis