Effect of spacing, seedling densityand nutrient management onthe performance of hybrid rice (Oryza sativa L.) in Southern Kerala

A field experiment was carried out during September–December of 2012 at the Cropping Systems Research Centre Karamana, Thiruvananthapuram, Kerala for assessing the production potential of hybrid rice in relation to spacing, seedling density and nutrient management. The productive tiller count hill⁻¹, number of filled grains panicle⁻¹ and 1000-grain weight did not vary significantly due to spacing. The productive tiller count (7.91 hill⁻¹) and 1000-grain weight (22.63 g) was maximum with a NPK dose of 90:45:45 kg ha⁻¹. The number of spikelets panicle⁻¹ was higher at closer spacing of 20 cm x 10 cm (144.14), higher seedling density of 2 seedlings hill⁻¹ (145.77), and higher nutrient level of 90:45:45 kg NPK ha⁻¹ (150.08). Sterility percentage was remarkably lower at wider spacing (24.63%), higher seedling density (23.43%) and higher nutrient level (23.41%). Grain yield was significantly higher (4.61 t ha⁻¹) at 2 seedlings hill⁻¹ and with 150:75:75 kg NPK ha⁻¹ (4.89 t ha⁻¹). Wider spacing (20 cm x 15 cm), seedling density (1 seedling hill⁻¹) and nutrient level (150:75:75 kg NPK ha⁻¹) resulted in higher net returns (10³ x 53.81 ha⁻¹, 10³ x 46.21 ha⁻¹ and 10³ x 57.39 ha⁻¹) and benefit: cost ratio (2.13, 1.98, 2.17), respectively. It can be concluded that hybrid rice ‘KRH-2’ was best performer in the wetlands of the Southern region of Kerala, when planted at a spacing of 20 cm x 15 cm with one seedling hill⁻¹ and supplied with a NPK dose of 150:75:75 kg ha⁻¹.