~ 135 ~ International Journal of Research in Agronomy 2025; 8(2): 135-140 E-ISSN: 2618-0618 P-ISSN: 2618-060X © Agronomy www.agronomyjournals.com 2025; 8(2): 135-140 Received: 02-11-2024 Accepted: 07-12-2024 Anil Kumar Keerthi Department of Soil Science and Agricultural Chemistry, College of Agriculture, Dharwad University of Agricultural Sciences, Dharwad, Karnataka, India Rajakumar GR Associate Professor, Department of Soil Science and Agricultural Chemistry, College of Agriculture, University of Agricultural Sciences, Dharwad, Karnataka, India Jagadeesh BR Professor, Department of Soil Science and Agricultural Chemistry, College of Agriculture, University of Agricultural Sciences, Dharwad, Karnataka, India Priya P Assistant Professor, Department of Agronomy, College of Hnumanmatti, University of Agricultural Sciences, Dharwad, Karnataka, India Diwan JR Professor, Department of Genetics and Plant Breeding, College of Agriculture, University of Agricultural Sciences, Dharwad, Karnataka, India Corresponding Author: Anil Kumar Keerthi Department of Soil Science and Agricultural Chemistry, College of Agriculture, Dharwad University of Agricultural Sciences, Dharwad, Karnataka, India Assessing different SSNM techniques to recommend optimum fertilizer dose under transplanted rice (Oryza sativa L.) Anil Kumar Keerthi, Rajakumar GR, Jagadeesh BR, Priya P and Diwan JR DOI: https://doi.org/10.33545/2618060X.2025.v8.i2c.2542 Abstract An experimental study was conducted during kharif 2023 at the Agricultural Research Station, Mugad, to evaluate different Site-Specific Nutrient Management (SSNM) techniques for determining the optimum fertilizer dose for transplanted rice. The split-plot design included three replications, with two rice varieties, Mugad Siri and Mugad Sugandha, as the main plots and various SSNM-based fertilizer rates as subplots. These subplots included Soil Test Crop Response (T2), Rice Crop Manager (T3), Nutrient Expert (T4), the Recommended Package of Practices (T1), and an absolute control (T5). The results indicated that the RCM (web source) treatment led to superior growth, nutrient uptake (124.22 kg ha -1 N, 27.73 kg ha -1 P, and 94.71 kg ha -1 K), grain yield (51.33 q ha -1 ), straw yield (71.25 q ha -1 ) and economics compared to other treatments, with Nutrient Expert (software) performing nearly as well as RPP. Mugad Sugandha had a higher grain yield (42.94 q ha -1 ), phosphorus uptake (22.05 kg ha -1 ) and economics, while Mugad Siri showed higher nitrogen uptake (103.19 kg ha -1 ), similar potassium uptake, and higher straw yield (65.83 q ha -1 ). The RCM treatment was effective for Mugad Sugandha in increasing phosphorus uptake grain yield and economics and for Mugad Siri in enhancing nitrogen and potassium uptake and straw yield. Among the SSNM treatments, RCM was significantly superior. Keywords: Rice crop manager, nutrient expert, soil test crop response, recommended package of practice Introduction Rice (Oryza sativa L.) is indeed a crucial staple food crop globally and particularly in India, with over 90 percent of the world ` s rice production and consumption taking place in Asia (Sun et al., 2022) [14] . Rice grown in varying climates with temperature ranging from 17 to 33 °C and rainfall of 100 to 5100 mm with an altitude of 2600 meters from mean sea level. The global demand for rice is indeed growing every year, and it is estimated that, by 2050, the requirement will be around 584 million tonnes (Samal et al., 2022) [11] . Growth and yield of rice are heavily dependent on various agronomic practices, and nutrient management is one of the most critical management practices that can significantly impact yield. If nutrients are not supplied in adequate amounts, it can lead to yield reduction and even crop failure. While fertilizers have undoubtedly boosted rice yields, their excessive application poses significant environmental and economic threats. This creates a dependence on ever-increasing fertilizer inputs, leading to diminishing returns and potential economic burdens on farmers. Therefore, it is essential to ensure that rice crops receive the necessary nutrients at the right time and in the right amount to achieve optimal growth and yield. Materials and Methods The experiment was conducted at the Agricultural Research Station (ARS), Mugad, during kharif 2023, Soil samples from the targeted plot were collected and analyzed for NPK status. The experiment followed a split-plot design with three replications, including two rice varieties: Mugad Siri (M 1 ) and Mugad Sugandha (M 2 ) as main plots, and various Site-Specific Nutrient Management (SSNM) treatments as subplots.