Assessment and mapping of soil fertility status in Byrapura micro-watershed of Nandi sub-watershed using geospatial techniques

Abstract

Soil fertility assessment is crucial for sustainable agricultural productivity and environmental management. This study aims to evaluate and map the soil fertility status of Byrapura micro-watershed in the Nandi sub-watershed. A systematic grid technique of soil sampling was adopted with a sampling interval of 320 m, collecting representative samples from 0-30 cm depth. These samples were analysed for key soil fertility parameters, including pH, electrical conductivity (EC), organic carbon (OC), available macronutrients (nitrogen, phosphorus and potassium), secondary (exchangeable calcium and magnesium and available sulphur and micronutrients (iron, zinc, manganese, copper and boron). The spatial distribution of these parameters was mapped using geospatial techniques to identify fertility variations across the micro-watershed. The results indicated that soil pH varied from moderately acidic to strongly alkaline (4.93 to 8.76) and the soils were non-saline in nature. Organic carbon content was observed to be low to high (2.30 to 11.70 g kg-1). Available nitrogen was found to be low to medium (87.81 to 435.90 kg ha-1), while available phosphorus (23.20 to 77.86 kg ha-1) and potassium (152.01 to 527.39 kg ha-1) were medium to high levels across the micro-watershed. Among the secondary nutrients, exchangeable calcium (6.00 to 25.00 cmol (p+) kg-1), exchangeable magnesium (4.00 to 17.00 cmol (p+) kg-1) and available sulphur (10.58 to 51.73 mg kg-1) were found to be sufficient. Micronutrient analysis revealed deficiencies in available zinc and available boron in specific locations, potentially impacting crop productivity. The fertility maps generated provide valuable insights into soil nutrient distribution, necessary for site-specific nutrient management recommendations. These findings can assist farmers and policymakers in implementing effective soil fertility improvement strategies, ensuring sustainable land use and crop production in Byrapura micro-watershed.