Soil stoichiometry patterns and their driving mechanisms: exploring nutrient dynamics in eucalyptus plantations in...

This study was conducted to investigate the impact of Eucalyptus plantations on soil physicochemical properties and nutrient stoichiometry in the Malakand Division, Pakistan. Four vegetation groups were evaluated: Eucalyptus-dominated forest, Eucalyptus-moderately distributed forest, Eucalyptus-low forest, and non-Eucalyptus forest. The study hypothesized that Eucalyptus-dominated forests would have lower soil nutrient contents, mainly total carbon (TC) and total nitrogen (TN), Although nutrient imbalances were observed, the variations were not statistically significant. Soil texture differed significantly different, with a higher sand content in Eucalyptus-dominated forests, whereas clay and silt were more predominant in non-Eucalyptus forests. Additionally, chemical properties such as pH, electrical conductivity, and phosphorus content varied significantly, influencing soil fertility. The C:N, C:P, and N:P ratios strongly differed among the vegetation groups, indicating alterations in soil nutrient cycling at Eucalyptus plantation sites. Redundancy analysis (RDA) revealed that soil textural properties such as clay (r = -0.87), silt (r = -0.74) and climatic factors such as precipitation (r = 0.33) and RH2M (r = -0.55) are important determinants of soil stoichiometry. Structural equation modeling (SEM) showed that geographic factors i.e., latitude, longitude, and elevation, negatively affect soil nutrients, including total carbon (-0.83), total nitrogen (-0.52), and total phosphorus (-1.04). The results revealed the negative impact of Eucalyptus plantations on soil nutrient dynamics, suggesting the need for sustainable land management strategies to mitigate soil degradation and maintain ecosystem balance. This study addresses the need for sustainable land use policies, such as afforestation and soil restoration practices, to reduce nutrient disturbance and maintain ecosystem balance. Further research is needed to examine soil nutrient stoichiometry and the broader ecological impacts of invasive Eucalyptus plantations in order to enlighten effective conservation and land management policies.