Soil quality assessment across different stands in tropical moist deciduous forests of Nagaland, India

To analyze the relationship between the management of three forest stand plantations and soil quality in the Dimapur district of the Northeastern Himalayan region, India, three forest soil profiles, covered by different species stands, at three depths were tested for 13 physical and chemical variables. Only four of these variables (electric conductivity, bulk density exchangeable Mg and available P) were included in a minimum data set, after using a varimax rotation algorithm in a principal component analysis, and subsequently used to calculate a soil quality index (SQI). Results showed higher SQIs in the surface layers (0-20cm depth) than in the deeper ones. Average weighed SQI varied significantly (P<0.05) through the three considered forest sites, with the lowest value at site FS3. These findings reveal that the approach used here is suitable for preliminary screening of the impact of a forestry species on soil, to aid in species selection and improve soil health for afforestation and reforestation projects.