Influence of stump diameter thickness and nutrient application on seedling biomass attributes in Pterocarpus santalinus Linn.f

Abstract

Pterocarpus santalinus Linn. f., a highly valued and endangered timber species of the Eastern Ghats, requires optimal nursery management to ensure successful establishment. This study evaluated the influence of stump diameter thickness and nutrient management on seedling biomass accumulation in P. santalinus. A factorial randomized block design with three stump diameter classes (< 3 mm, 3-5 mm, > 5 mm) and eight nutrient treatments was laid out at Gudagur Forest Nursery, Haveri district. The results demonstrated a significant effect of stump diameter and nutrient treatments on fresh and dry biomass at 180 days after treatment. The largest stump diameter class (D₃ > 5 mm) recorded the highest total fresh biomass (12.33 g) and dry biomass (5.78 g), while the smallest stumps had the lowest biomass accumulation. Among nutrient treatments, T₆ (0.5 g NPK + 33 g poultry manure per seedling) was most effective, resulting in 13.25 g of fresh biomass and 6.54 g of dry biomass. The interaction between D₃ and T₆ produced the maximum total fresh biomass (16.97 g) and dry biomass (8.80 g), indicating synergistic effects of stump size and integrated nutrient management. The findings highlight that using larger stump diameters in combination with balanced nutrient inputs (D3T6) can significantly enhance early seedling vigor and biomass production. This has practical implications for large-scale propagation and reforestation programs involving P. santalinus.