Standardization of planting time, spacing and nutrient management for traditional red-husked scented rice (Oryza sativa) in West Bengal

The effect of planting time (10 July, 25 July and 10 August), spacing (15 cm x 15 cm and 20 cm x 15 cm), and nutrient management [100% recommended dose (RD) of organic, 100% RD inorganic, and 50% RD organic + 50% RD inorganic] of small-grained red-husked scented "Lal Badshabhog" rice was studied during the wet season of 2014 and 2015 in a split split-plot design at Bidhan Chandra Krishi Viswavidyalaya, Kalyani, Nadia, West Bengal, India. Early-planted crop (10 July) produced tallest plants at maturity (160.2 cm) and leaf-area index (LAI) at 84 days after transplanting (DAT) (4.88), but late planting (10 August) resulted in better tiller production at 56 DAT (285.4/m²). Mean light extinction co-efficient (k) of the variety was 0.40 and 0.37 at 56 and 84 DAT, respectively. ‘Lal Badshabhog’ rice planted on 10 August recorded the highest grain yield (2.72 t/ha), which was 3.77 and 12.76% higher over 25 July and 10 July planting, respectively. Close planting (15 cm x 15 cm or 44 hills/m²) could improve the grain yield of ‘Lal Badshabhog’ rice by 3.95% (2.63 vs. 2.53 t/ha) over wider spacing (20 cm x 15 cm or 33 hills/m²), and application of 100% RD (N 50, P₂O₅ 25, K₂O 25 kg/ha) through chemical fertilizers resulted in higher grain yield (2.64 t/ha), net returns (₹32,900/ha) and benefit: cost ratio (2.02) compared to organic or integrated nutrient management. Mean N, P and K uptake by "Lal Badshabhog" rice at maturity was 41.2, 15.8 and 30.3 kg/ha, respectively, and the crop grown under integrated nutrient management (50% RD organic + 50% RD chemical fertilizer) left the field with better residual status (+5.9% N, +28.3% P₂O₅ and +1.7% K₂O) over initial values after 2-year study in Gangetic alluvium soil.