Assessing Soil Fertility in Huliginahal Micro-watershed, Karnataka, India: A Basis for Site-specific Recommendations

The measurement of soil accessible nutrient levels/contents of a region using the global positioning system (GPS) can assist in creating site-specific balanced fertilizer recommendations and understanding the condition of soil fertility spatially and temporally. Soil samples were collected at 320m grid intervals from the Huliginahal Micro-Watershed in the northern dry zone of Karnataka, India, and tested for fertility characteristics. The analytical data were analysed, and statistical parameters such as maximum, minimum, mean, and standard deviation were calculated. Soil fertility maps for each parameter were generated in a GIS context using ArcGISv10.4. The soil was neutral to very strongly alkaline, while the EC ranged from non-saline to slightly saline. For the available soil organic carbon (OC) content 43.82 % of the study area was low, while 41.4 % was medium. Most of the study area (93.47%) recorded low available nitrogen. Available phosphorus (P) was low to medium in large parts of the study area (93.99%), with available potassium (K) being medium in a high percentage of the area (77.49%). Available sulphur (S) was medium to high in 41.56% and 52.44% of the area, respectively. Regarding available micronutrients, zinc (Zn), iron (Fe), copper (Cu) and manganese (Mn) were sufficient in more than half of the micro-watershed area. The mapping of nutrients by the GIS technique has thrown light on the soil fertility status of the Huliginahal Micro-Watershed area.