Assessment of productivity potential of upland soils of south eastern ghats of Tamil Nadu, India

Soil productivity potential was evaluated in uplands of South-Eastern Ghats (SEG) of Tamil Nadu using large-scale soil mapping (1:10000 scale) information. Major landforms on peninsular granite gneiss are divided into hillside slope (P1), foothills (P2), upper pediment (P3), and lower pediment (P4). Soils are shallow (<50 cm) to deep (100150 cm), well-drained, non-gravelly to gravelly, slightly acidic to slightly alkaline (pH 5.71 to 8.29) in reaction and nonsaline (EC 0.03 to 0.25 dS m⁻¹). The soil texture varied from loamy sand to sandy clay loam with rich organic carbon in surface soils and decreasing with soil depth. Soils are classified into Typic Haplustalfs (P1), Lithic Haplustalfs (P2), Kanhaplic Haplustalfs (P3), and Kanhaplic Rhodustalfs (P4) under different landforms. Soil properties in different landforms are significantly correlated with each other. Two factors explained the variability of soil characteristics in different landforms in hills (58%), foothills (65%), upper pediments (61%), and lower pediments (54%) respectively. Assessment of productivity potential, upper (P3) and lower pediment (P4) soils are average (30.1 to 33.4) to good (34.7) productivity for crops and pasture, extremely poor for trees than a hill (P1) and foothills (P2). Results revealed the significant soil erosion and poor nutrient status impact on a crop production system. Hence, adaptation of appropriate soil and water conservation measures and nutrient management will improve soil quality and crop productivity.