Different Prosopis species influence sodic soil ecology by favouring carbon build-up and reclamation in North-West India

Prosopis species is a multipurpose N-fixing leguminous tree that grows naturally in semi-arid and arid environments. These trees are reported to ameliorate and rehabilitate salt-affected soils through its diverse inputs and tolerance to high salinity. However, scanty and scattered information is available on reclamation capacity and soil ecology transformations of different Prosopis spp. under different soil depths. The first aim of this study was to examine changes in soil properties under different Prosopis spp. (of 12 years old plantations) at the research farm, ICAR-Central Soil Salinity Research Institute, Karnal, Haryana, India. The second aim was to determine the most influential soil properties that accounted for the most variation in the Prosopis spp. plantation. The results indicated that irrespective of different Prosopis spp. Plantation, soil pH, electrical conductivity (EC), bulk density, the concentration of Na+, HCO3- and CO3- decreased significantly whereas, mineral N (NO3--N and NH4+-N), soil organic C (SOC), soil carbon stock, microbial biomass C (MB-C) and the concentration of K+ increased significantly. The highest reduction in EC value was noticed under P. juliflora (64.5%) followed by P. chilensis (61.5%) and P. articulata (59.8%) as compared to the control (barren land). Prosopis juliflora increased the MB-C, averaged across the soil depth by 14.8% and 27.5% over P. alba and P. articulata, respectively. MB-C averaged across the Prosopis spp. decreased with increased soil depth and remarkable influence was observed up to 75 cm of soil depth. The magnitude of increase in SOC content and soil carbon stock was higher under P. alba followed by P. juliflora than rest of the Prosopis spp. in the surface (0-15 cm) than sub-soil (15-105 cm) layers. With the predicted increase in area under salt-affected soils due to climate change and anthropogenic reasons, it is crucial to develop the management practices and technologies particularly bio-amelioration which will not only reclaim salt-affected soils but also increase the carbon content to restore the fertility of these soils.