Growth Performance and Soil Fertility Dynamics in Nutrient Managed Acacia auriculiformis Based Silvipastoral System

Abstract

A study conducted at the experimental site of the All India Co-ordinated Research Project on Agroforestry at Odisha University of Agriculture and Technology in Bhubaneswar, India, examined the effect of nutrients on growth and soil fertility status in Acacia auriculiformis-based silvipastoral system. In the study, the combination of Acacia auriculiformis with Guinea grass achieved the highest plant growth metrics: plant height (14.59m), DBH (16.56cm), collar girth (52.03cm), and crown spread (3.30m) at 90 MAPS (Months After Planting). The subplot N1 showed the greatest values for these characteristics among the subplots. The highest levels of organic carbon, available nitrogen, phosphorus and potassium were observed in the main plot with Acacia auriculiformis and Guinea grass, as well as in subplot N1. The soil texture was classified as loamy sand, with Thin Napier displaying the highest bulk density at 1.39, while subplot N1 recorded 1.38. Maximum porosity was noted in the main plot with Nandi grass (46.6%) and subplot N4 (47.2%). Chlorophyll content across all grasses peaked in August due to rainfall, with Guinea grass leading, followed by Thin Napier and Nandi grass. Subplot N1 showed the highest chlorophyll content among subplots, followed by N2, N3, and N4. Solar radiation interception mirrored chlorophyll trends, with the highest readings recorded in June. Soil moisture compared to open field was highest in July, with the main plot Guinea grass recording 1.98% and the subplot N1 maintaining the maximum soil moisture among subplots at 1.42%. Among the main plots the highest figures of soil organic carbon were exhibited from main plot Acacia auriculiformis + Guinea grass (10.85 Mg ha-1) and sub plot N1 (8.69 Mg ha-1). The analysis revealed that the silvipastoral system combining Acacia auriculiformis and Guinea grass, supplemented with appropriate fertilizer doses, was the most productive in terms of growth and soil fertility among the systems studied.