Agronomic Management of Bacterial Leaf Blight of Rice (Oryza Sativa L.) Disease and Yield Enhancement Through Different Combinations of Nitrogen and Potash Doses

Abstract

This research trial was conducted at Rice Research Institute, Kala Shah Kaku, during kharif 2010, to assess the influence of nitrogen (N) and potash (K) on the incidence and severity of Bacterial leaf blight of rice (BLB) (Oryzae sativa L.). The experiment was laid out in a Randomized Complete Block Design in factorial arrangement with three replications using net plot size of 2.25 m × 6.0 m. The experiment was comprised of 0, 75, 100, 125 kg N ha-1 and 0, 50, 75, 100 kg K ha-1. Thirty days old nursery of Super Basmati was transplanted manually in puddle field. Data on disease severity and yield parameters of rice were recorded using standard procedures. Yield parameters were affected significantly by various combinations of N & K. In case of BLB, minimum diseased leaf area (15.76 % DLA) was observed where N alone was applied @ 75 kg ha-1 in contrast to 125 kg N + 50 kg K ha-1 which showed maximum DLA (43.17 %). Highest paddy yield of 4.32 t ha-1 was recorded where rice was fertilized @ 75 kg N + 100 kg K ha-1, while the minimum paddy yield of 2.40 t ha-1 was obtained where only 75 kg K ha-1 was applied. Optimum fertilization @ 75 kg N + 100 kg K ha-1 improved the harvest index value up to 20.32 %. Minimum harvest index of 15.61 % was obtained where K alone was applied at the rate of 100 kg ha-1. Maximum gross income (Rs.154652 ha-1), net return (Rs.154652 ha-1), and BCR (1.32) were obtained where rice crop was fertilized @ 75 kg N and 100 kg K ha-1.