Nitrogen optimization for boosting yield, quality and economics of ‘Chakhao Amubi’ black rice (Oryza sativa L.)

Abstract

Optimization of nitrogen (N) levels and sources is crucial to unlock the productivity potential of black rice. A field experiment was executed at Bhubaneswar, Odisha, India in rainy season of 2024 using black rice cv, ‘Chakhao Amubi’ as the test crop. Three N levels (L1 - 30, L2 - 60, and L3 - 90 kg/ha) were allocated to main plots, and five sources, i.e., combinations of inorganic N (urea) and farm yard manure (FYM), were allocated to subplots, in split-plot design replicated thrice.  The N sources were S1: Urea N (100%), S2: FYM N (100%), S3: Urea N (75%) + FYM N (25%), S4: Urea N (50%N) + FYM N (50%), S5: Urea N (25%) + FYM N (75%). Among N levels, both L3 and L2 excelled L1 for grain, biological yield, gross return and net return, but L2 was superior to L3 for milling percentage. Both L1 and L2 were superior to L3 for amylose (%), gel consistency and alkali spreading value. Among N sources, S3 was the best for productivity, profitability and quality. The treatment combination L2S3 produced grain yield, straw yield, gross return, net return and B:C of 3633 kg/ha, 4460 kg/ha, 263.2 x103 ₹/ha, 199.30 x103 ₹/ha and 3.12, respectively, being at par with L3S3 (4143 kg/ha, 4906 kg/ha, 299.83 x103 ₹/ha, 233.25 x103 ₹/ha and 3.50). The treatment combination L2S3 can be adjudged as the best nitrogen management strategy for sustained yield and quality of black rice in coastal ecosystems of Eastern India.