Soil quality under different tree species in an urban university campus: a multidimensional study

Abstract

Soil is vital for food security and ecosystem nutrient recycling. Rapid infrastructure development projects requiring mineral resource extraction have led to an overall decrease in soil quality. Due to a higher environmental footprint, the soil quality in cities has declined quickly, necessitating continuous monitoring and evaluation. Educational institutions are traditionally not considered for such monitoring. Thus, the present study investigated the soil status under 10 different tree species at Maharshi Dayanand University (MDU) located in Rohtak city. Using various digital and volumetric methods, 20 physicochemical parameters including sand, silt, clay, pH, electrical conductivity (EC), organic matter (OM), macronutrients and micronutrients, etc., were analyzed. Sampling was performed at four depths (0–10, 10–20, 20–30 and 30–40 cm) to collect a total of 40 composite samples. Repeated measures of one-way analysis of variance (ANOVA) and pairwise comparison were used to detect significant differences. Soil parameters were significantly different among various tree species (p < 0.05). The soil nutrient index value (SNIV) classified sand (3), pH (2.62), Ca²⁺ (2.82), Cu (2.60) and Fe (2.65) in the high fertility class. Network analysis demonstrated the effects of physicochemical parameters on OM and nutrients. The structural stability index (SSI) appropriated 50% of the samples as thoroughly degraded (SSI < 5%). Principal component analysis (PCA) produced five significant components and designated N, P, Cu and OM as the most critical soil chemistry variables. Hierarchical cluster analysis (HCA) produced 3 clusters for tree species with similar soil properties. The soil under F. virens is the most productive. Overall, the campus soil is alkaline, nutrient deficient and surface layers are more fertile. The results obtained and the customized solutions provided in this article may help to improve the campus soil and aid in sustainable soil use, conservation and management. This may also encourage other campuses around the globe to assess their soil status.