Assessing Division-level Variability in Soil Nutrient Retention in a Tropical Forest Reserve: Evidence from the Amrabad Tiger Reserve, India

Abstract

Aim: The present study aimed to evaluate division-wise variability and interrelationships of key soil physico-chemical properties governing nutrient retention in the Amrabad Tiger Reserve (ATR), a tropical dry deciduous forest ecosystem of the Eastern Ghats, India. Study Design: A field-based observational study was conducted, and the data were statistically analysed using one-way analysis of variance (ANOVA) followed by Tukey’s HSD test, along with Pearson’s correlation analysis to examine relationships among variables. Place and Duration of the Study: Soil sampling was carried out across three administrative divisions—Achampet, Amrabad, and Nagarjuna Sagar—within the Amrabad Tiger Reserve, Telangana, India, from 2023 to 2025. Methodology: A total of 100 composite soil samples were collected from ten forest ranges at a depth of 0–15 cm. Samples were analysed for soil reaction (pH), electrical conductivity (EC), organic carbon (OC), and available nitrogen (N), phosphorus (P), and potassium (K) using standard and widely accepted laboratory procedures. Statistical analyses were employed to assess spatial variability and interrelationships among soil properties. Results: Significant division-wise variation was observed for soil pH, EC, and available N, P, and K (p < 0.01), whereas organic carbon did not differ significantly among divisions. Nagarjuna Sagar soils exhibited higher pH but comparatively lower nitrogen availability, while Amrabad showed superior nutrient status, particularly for nitrogen, phosphorus, and potassium. Pearson’s correlation analysis identified organic carbon as a key regulator of nutrient availability, showing strong positive associations with available nitrogen (r = 0.355) and potassium (r = 0.381). Conclusion: The study reveals pronounced spatial heterogeneity in soil nutrient retention within ATR, driven by fine-scale variations in geomorphology, vegetation, and organic matter dynamics. Organic carbon emerged as the central factor controlling nutrient availability, underscoring the need for site-specific soil management and conservation strategies to sustain productivity and ecosystem resilience in tropical dry forest reserves.