Evaluation of Soil Fertility Status Using Macro-, Micro-Nutrients and Nutrient Index Values in the KRISAT Farm, Tamil Nadu

Abstract:

A study was conducted to evaluate the fertility status of soils in the instructional farm of Krishna College of Agriculture and Technology (KRISAT), Usilampatti, Tamil Nadu, using macro- and micronutrient analysis and nutrient index values. Sixty-two geo-referenced surface soil samples (0–15 cm) collected from different survey numbers were analyzed for available nitrogen (N), phosphorus (P), potassium (K), iron (Fe), manganese (Mn), zinc (Zn), copper (Cu) and organic carbon following standard analytical procedures. Available nitrogen ranged from 50.0–71.4 kg ha⁻¹, phosphorus from 1.4–25.0 kg ha⁻¹ and potassium from 52–265 kg ha⁻¹. DTPA-extractable Fe, Mn, Zn and Cu ranged from 2.44–8.73, 2.31–7.60, 0.34–1.21 and 0.16–1.92 mg kg⁻¹, respectively, while organic carbon ranged from 0.22–0.31%. Nutrient index values indicated low fertility for nitrogen, copper and organic carbon; low to medium fertility for phosphorus and potassium; and medium fertility for iron, manganese and zinc. The study highlights the need for site-specific nutrient management and integrated nutrient management practices to improve soil fertility, enhance fertilizer use efficiency and sustain crop productivity in the KRISAT farm.