Spatial variability map for soil fertility of Sugarcane Research Station Farm, Cuddalore, Tamil Nadu using GIS techniques

A study was conducted during 2023-2024, total of 144 surface soil samples were collected from the Sugarcane Research Station in Cuddalore, Tamil Nadu. GPS coordinates (Latitude °N and Longitude °E) were recorded for each sampling site using a Garmin eTrex Vista HCX GPS. Field maps were created and digitized according to the sampling locations. Soil samples were processed and analyzed for physicochemical properties and fertility parameters. The results showed that the soils were neutral to slightly alkaline and non-saline. Soil fertility groupings revealed low to medium organic carbon, low to medium available nitrogen, medium available phosphorus, medium to high available potassium and medium to high available sulphur. Over 80 % of the soil samples had sufficient levels of Cu, Fe and Mn, based on DTPA extractable micronutrients. However, 58 % of the soil was below the critical level for Zn, while 42 % had sufficient Zn. Nutrient index values indicated low status for organic carbon, available nitrogen and Zn, medium for available phosphorus and adequate levels for available sulphur. For micronutrients, DTPA-Mn was adequate, DTPA-Cu and Fe were high and DTPA-Zn was marginal. Thematic maps showed spatial variability across the station. To sustain soil fertility, deficiencies in areas with poor fertility should be addressed using organic or inorganic amendments. Following soil test-based fertilizer and micronutrient recommendations is essential for improving nutrient availability and maintaining soil health for sustainable crop production.