Influence of Land-Use Types and Environmental Variables on Soil Properties in Forest Ecosystems of Chittagong, Bangladesh

Abstract

Soil properties play a significant role in ecosystem productivity, especially in forest areas where land-use and environmental variables (such as slope and altitude) strongly influence soil stability and fertility. The objective of this study was to assess the impact of land-use types and environmental variables on soil properties in forest ecosystems in southeast Bangladesh. A total of 81 samples were collected from nine different land-use forest sites, with altitudes ranging from 26.43 m to 106.35 m and slope gradients from 26.07% to 77.30% across the land-use types. About ten soil properties were analyzed using appropriate methods, such as bulk density (BD), soil pH, soil organic carbon (SOC), total nitrogen (TN), carbon to nitrogen ratio (C:N), available phosphorus (AP), available potassium (AK), available sulfur (AS), available zinc (AZn) and available boron (AB). The analysis of variance (ANOVA) results showed significant variations in soil properties among land-use types (p < 0.001). Post-hoc analysis was also applied to analyze and compare the mean significant differences between each property under different land-use types. Nutrient Properties such as TN, AP, AK, AS, AZn, and AB, as well as SOC, were higher in natural forests and agroforestry systems than in shifting cultivation and monoculture forests. In contrast, BD and soil pH were highest in the acacia forest compared to the natural forest. Considering environmental variables, correlation analysis revealed a positive relationship with slope, altitude, and BD, but a negative relationship with SOM, TN, AS, and AB. Among the soil properties, BD, pH, and the C:N ratio showed negative correlations, whereas SOC, TN, AP, AK, AS, AZn, and AB exhibited positive correlations. Additionally, regression analyses revealed a significant relationship between BD, SOC, TN, AS, AB, and slope, as well as between SOC and altitude. Land-use and environmental variables strongly affect soil properties and fertility, with steeper slopes and high altitude showing compacted, acidic, low SOC, and low nutrient content in soil. Future research should investigate the combined effects of land-use and seasonal variation, as well as the role of conservation methods in reducing soil degradation in the study area.

The Chittagong Univ. J. Sci. 46(1): 178-205, 2025