Journal of the Indian Society of Soil Science

Spatial variability analysis was done for soil physicochemical properties viz., pH₂, EC₂, organic C and bulk density of surface and sub-surface soil samples collected grid-wise (2m x 2m) at different possible distances from trees under 10-years-old Prosopis juliflora and Terminalia arjun plantations. The statistical variability ranged from 6 to 8% for pHz and 44 to 64% for organic carbon under Prosopis juliflora plantation. However, under T. arjun plantation, the statistical variability ranged from 6 to 7% for pH₂ and 45 to 54% for EC₂. The mean values of pHz of soil were 9.1 and 9.6 at 0–15 em, 9.8 and 10.0 at 15–30 cm depths under P. juliflora and T. arjun, respectively. The organic carbon accumulation in surface soil under P. juliflora plantation was significantly higher than that under T. arjun. Prosopis was found to be comparatively more efficient for soil reclamation than T. arjun. The semivariograms of the soil physicochemical parameters indicated moderate to strong spatial dependence except bulk density at 0–7.5 and 7.5–15 cm under P. juliflora. The experimental semivariograms of bulk density under P. juliflora were not spatially structured. Hence, inverse distance method was used for spatial interpolation of these data. The kriged and inverse distance maps provided the regions and loops of pH, EC, organic C and bulk density with distinct values and explained the quality of heterogeneity of reclamation under both the tree species. The patches or loops of higher and lower values of the physicochemical parameters at some places were interrelated. Still some loops or regions were not related to each other. The spatial distribution of soil parameters and relation among these distributions may be a product of multiple ecological processes such as biomass distribution, canopy patch pattern, root distribution, under story vegetation and stand dynamics and microbial distribution over a span of 10 years.