Soil Fertility Status of Different Grape Growing Orchards in Nandi Valley, Karnataka, India

Abstract

A comprehensive study evaluated the Soil fertility status of different grape growing orchards in Nandi Valley, Karnataka - Bangalore Blue, Dilkush, Sharad Seedless and Red Globe. A total of 200 soil samples were collected from 100 grape gardens, with 25 gardens per variety. From each garden, two soil samples were taken: surface soil (0–20 cm) and sub-surface soil (20–40 cm) near the root zone of grape vines. The analysis revealed significant variability in soil fertility status among the grape varieties and depths. Soil pH and electrical conductivity (EC) increased with depth, with Dilkush surface soils showing a neutral pH (7.22), while Bangalore Blue recorded the lowest EC (0.31 dSm⁻¹). Organic carbon (OC) and cation exchange capacity (CEC) decreased with depth, with Sharad Seedless surface soils exhibiting the highest OC (7.59 g kg⁻¹) and CEC (17.87 cmol(p⁺) kg⁻¹). Available nitrogen (N), phosphorus (P), and potassium (K) also declined with depth. Red Globe recorded the highest surface N (413.63 kg ha⁻¹), Bangalore Blue had the highest P (63.07 kg ha⁻¹) and Sharad Seedless had the highest K (392.24 kg ha⁻¹). Exchangeable calcium (Ca) and magnesium (Mg) increased with depth, with Red Globe soils showing the highest Ca (4.72 meq/100 g) and Mg (2.54 meq/100 g). Available sulphur (S), DTPA-extractable micronutrients (Fe, Mn, Cu, Zn), and hot water-soluble boron (B) declined with depth, with Sharad Seedless soils exhibiting the highest levels of micronutrients and boron. These results provide a scientific basis for soil management strategies aimed at optimizing grape production in the Nandi Valley region.