Chemical properties of soils in relation to forest composition in moist temperate valley slopes of Garhwal Himalaya, India

The present study was undertaken in moist temperate forest of Mandal-Chopta area in the Garhwal region of Uttarakhand, India. The aim of the present study was to assess the chemical properties of soils in relation to the forest structure and composition. Twelve forest types according to the altitude, slope aspect, and species composition were selected for the study. Chemical properties of the soil, i.e., total nitrogen (N), available phosphorus (P), available potassium (K), organic carbon (C), soil organic matter (SOM), pH and C:N ratios were analyzed for three different depths viz., (i) ‘Upper’ (0–10 cm), (ii) ‘Middle’ (11–30 cm), and (iii) ‘Lower’ (31–60 cm) in all the selected forest types. Phytosociological and diversity parameters viz. total basal cover (Gha⁻¹), stem density (Nha⁻¹), tree species richness (SR), Simpson concentration of dominance and Shannon–Wiener diversity index ([Formula: see text]) were also calculated for each forest type. Values of N, P, K, C, SOM, C:N ratio and pH ranged from 0.17 to 0.45 %, 2.73 to 20.17 ppm, 40.67 to 261.17 ppm, 2.29 to 4.31 %, 3.95 to 7.43 %, 8.12 to 14.49 and 5.47 to 6.67, respectively. N showed a positive relationship with C and K. P was positively correlated with C and negatively correlated with altitude. P was higher in the soil of lower horizons of all the forest types. K was found to be positively correlated with altitude, C and N. pH of all the forest types was slightly acidic. C was comparatively higher in mixed broad-leaved forest types. No relationship between altitude and C was observed, which may be due to different composition of forest types along the altitudinal gradient and their differential decomposition rates. C content decreased with the depth of the soil. C showed positive correlation with N, P, and K. N showed a positive correlation with Gha⁻¹. K showed a negative correlation with SR and [Formula: see text]. P showed no relationship with the phytosociological parameters. This study also provides the comparisons between the results of chemical analysis of the present study with numerous other previous studies in the temperate Himalayan region of the Uttarakhand. The values of soil chemical properties of the present study in most of the forest types are on the higher end than the values previously recorded for the other similar forests of the region. The possible reason being luxuriant vegetation and undisturbed nature of these forest types, which is evident from higher values of diversity and other phytosociological parameters.