Evaluation of soil fertility status of Regional Agricultural Research Station, Tarahara, Sunsari, Nepal

Soil fertility evaluation of an area or region is most basic decision making tool for the sustainable soil nutrient management. In order to evaluate the soil fertility status of the Regional Agricultural Research Station (RARS), Tarahara, Susari, Nepal. Using soil sampling auger 81 soil samples (0-20 cm) were collected based on the variability of land. The collected samples were analyzed for their texture, structure, colour, pH, OM, N, P 2 O 5 , K 2 O, Ca, Mg, S, B, Fe, Zn, Cu and Mn status. The Arc-GIS 10.1 software was used for the preparation of soil fertility maps. The soil structure was granular to sub-angular blocky and varied between brown- dark grayish brown and dark gray in colour. The sand, silt and clay content were 30.32±1.4%, 48.92±0.89% and 20.76±0.92%, respectively and categorized as loam, clay loam, sandy loam, silt loam and silty clay loam in texture. The soil was moderately acidic in pH (5.98±0.08). The available sulphur (2.15±0.21 ppm), available boron (0.08±0.01 ppm) and available zinc (0.35±0.03 ppm) status were very low, whereas extractable magnesium (44.33±6.03 ppm) showed low status. Similarly, organic matter (2.80±0.07%), total nitrogen (0.09±0.004 %), extractable calcium (1827.90±45.80 ppm) and available copper (1.15±0.04 ppm) were medium in content. The available phosphorus (39.77±5.27 ppm), extractable potassium (134.12±4.91 ppm), and available manganese (18.15±1.15 ppm) exhibits high status, while available iron (244.7±19.70 ppm) was very high. The fertilizer recommendation can be done based on determined soil fertility status to economize crop production. Furthermore, research farm should develop future research strategy accordance with the prepared soil data base.