Impact of tree spacing and ginger rhizome treatments on soil physicochemical properties in agroforestry systems

Soil health is a critical factor influencing agricultural productivity, especially in agroforestry systems where tree-crop interactions affect nutrient availability. This study evaluated the impact of different kadam (Neolamarckia cadamba) spacing and different ginger rhizome treatments on soil pH, electrical conductivity (EC), organic carbon, and macronutrient availability in an intercropping system. The experiment was conducted at the Forestry Research Farm, Rani Lakshmi Bai Central Agricultural University, Jhansi, where ginger was intercropped with Neolamarckia cadamba at three different spacings: 5m × 5m, 5m × 4m, and 5m × 3m. The findings revealed that soil pH was not significantly affected by tree spacing or ginger treatment, with minor variations observed at different crop growth stages. Electrical conductivity (EC) remained relatively stable across treatments, with the highest values recorded under sole cropping (0.20 dSm⁻¹) at the final stage. Soil organic carbon (SOC) increased with reduced tree spacing, with the highest content (0.51%) recorded in 5m × 3m spacing, while the lowest (0.39%) was observed under sole cropping. Available nitrogen (N), phosphorus (P), and potassium (K) were significantly influenced by tree spacing, with the highest values recorded under closer spacing (5m × 3m), indicating improved soil fertility due to enhanced organic matter accumulation. The findings suggest that closer tree spacing enhances soil organic matter and nutrient availability, benefiting long-term soil health in agroforestry systems. However, the stability of soil pH and EC implies minimal competition effects. These results contribute to optimizing agroforestry models for improved sustainability and productivity.