Soil samples from Nilgund sub-watershed in northern dry zone of Karnataka were drawn at 250 m grid intervaland assessed for their fertility parameters.  Analytical data was interpreted and statistical parameters like range, meanstandard deviation and coefficient of variation were calculated for each parameter . Soil fertility maps were prepared for eachparameter under Geographic information system (GIS) environment using Arc GIS v 10.4. Soils were neutral to verystrongly alkaline with non saline to slight salinity . Soil organic carbon content was low.  Available nitrogen was low, availablephosphorus was low to medium, available potassium was medium to high and sulphur was medium. Regarding availablemicronutrients, zinc, boron and iron were deficient in about half of the sub watershed area whereas, copper and manganesewere sufficient in the soils. The mapping of nutrients by GIS technique in the sub watershed revealed that, available N, P ,S, Zn and Fe are important soil fertility constraints.Key words: Geographic information system, Soil fertility constraints, Soil fertility map, Watershed