Vol. 12, Issue 2 (2023)

Author(s):
Rozalin Nayak, Manoranjan Satapathy, Bamashankar Rath and Rabindra Kumar Nayak

Abstract:
The need to sustain high rice yields as well as to enhance the nitrogen use efficiency has led to site specific management of nitrogen by various methods and tools. A field experiment was conducted during kharif seasons of 2020-21 and 2021-22 at Agronomy Main Research Farm, Odisha University of Agriculture and Technology, Bhubaneswar. The experiment was carried out in split plot design with six main plots treatments allotted to rice i.e. Soil test based nitrogen (100 kg N/ha), 75% N through soil test based nitrogen (STBN) + 25% N through FYM, 75% N through STBN + 25% N through vermicompost, N @ 20 kg at basal and at LCC < 3, N @ 20 kg at basal and at SPAD < 35 and no nitrogen during kharif and three sub plot treatments i.e. lime @ 0.2 LR, gypsum @ 250 kg/haand lime @ 0.2 LR + gypsum @ 250 kg/ha to groundnut during rabi each in three replications. Recommended doses of P₂O₅ and K₂O @ 40 kg/ha each to rice and N- P₂O₅- K₂O @ 20-40-40 kg/ha were applied to groundnut. As per the results, application of 75% N through STBN + 25% N through vermicompost recorded maximum grain yield (5128 kg/ha), straw yield (5707 kg/ha) and harvest index (47.31%) of rice which were found at par with 75% STBN + 25% N through FYM followed by LCC based treatment being at par with the STBN and SPAD based nitrogen management treatments respectively. Nitrogen, phosphorus and potassium uptake in grain, straw and total were higher in the treatment receiving 75% N through STBN + 25% N through vermicompost which was at par with 75% N through STBN + 25% N through FYM, N @ 20 kg at basal and at LCC < 3 and STBN treatment. Total uptake of 87.77, 22.38 and 109.84 kg/ha of N, P and K were recorded in 75% N through STBN + 25% N through vermicompost treatment with an increment of 36.8, 34.7 and 33.3% over the no nitrogen treatment. Application of 75% N through STBN + 25% N through vermicompost to rice crop resulted in higher internal nitrogen use efficiency (58.55 kg per kg N uptake) and physiological nitrogen use efficiency (71.22 kg yield increase per kg increase in N uptake) but application of N @ 20 kg at basal and at LCC < 3 resulted in higher partial factor productivity of applied N (69.80 kg yield per kg nitrogen applied) followed by N @ 20 kg at basal and at SPAD < 35.