Species-specific root architecture and its role in soil nutrient dynamics in a multispecies tree stand

Root system architecture (RSA) is important for determining tree stability, nutrient uptake and soil health, as well as for understanding interspecies differences in subtropical agro-ecosystems. Understanding RSA helps clarify species differences in nutrient uptake and soil interactions. The work was conducted to assess root intensity and soil properties of tree species (Pongamia pinnata, Cassia fistula, Tectona grandis, Aegle marmelos and Dalbergia sissoo) at Sher-e-Kashmir University of Agricultural Sciences and Technology (SKUAST), Jammu, India. Fine roots and coarse roots, as well as total root intensity, were measured using the profile wall method at five depth intervals (0–10, 10–20, 20–30, 30–40 and 40–50 cm). Soil nutrient parameters were measured at four soil depth intervals (0–15, 15–30, 30–45 and 45–60 cm). Root intensity demonstrated significant interspecific variation, with D. sissoo showing the highest fine root intensity (FRI) (2523.50 no. m-²), followed by P. pinnata and T. grandis, with most fine roots concentrated in the upper 30 cm. Tectona grandis recorded the highest coarse root intensity (1425.75 no. m-²). Soil analysis showed that P. pinnata and D. sissoo had higher surface nitrogen, phosphorus, potassium and organic carbon compared to other species. These findings highlight the promising roles of D. sissoo, T. grandis and P. pinnata, which exhibited intensive root spread, in promoting soil stabilisation and nutrient cycling in subtropical agroforestry systems.