Tree Plantation Established with Saline Groundwater on Degraded Calcareous Soils of Dry Regions of North-Western India as an Option for Biomass Production and Soil Amelioration in the Scenario of Changed Climate

A long-term field study was conducted to assess the performance of 31 potential tree species of economic importance for their biomass production and rehabilitation of calcareous soils using saline groundwater in low rainfall areas. Tree saplings were planted in the sill of the furrows, which were established and irrigated with saline groundwater (EC 9.3 dS m-1) available at site. Irrigations were provided regularly (4-6 times year-1) for the initial 3 years, thereafter only once in a year for the next 5 years, and kept rainfed afterwards up to 20 years. Survival, growth, biomass production, and water-use-efficiency of the tree species and changes in underneath soil properties were monitored during the study period. The top performer species were Tamarix articulata, Acacia nilotica, A. tortilis, Prosopis juliflora, Eucalyptus tereticornis, Azadirachta indica were Cassia siamea in given order. . Supplemental irrigation/s produced higher water-use-efficiency of different trees during initial 4-8 years than that of the earlier reported rainfed conditions. Tamarix articulata recorded highest (42.79 Mg ha-1) and Guazuma ulmifolia lowest (2.01 Mg ha-1) water-use-efficiency for the total growth period. After 20 years, total aboveground biomass production ranged from 123 to 391 Mg ha-1; being maximum for Tamarix articulata. With tree growth, soil organic carbon increased but CaCO3 and exchangeable sodium percentage (ESP) decreased in surface 30 cm soil layer. Thus, planting of the successful tree species with available saline groundwater can improve soil properties and carbon assimilation in tree biomass, and lead to productive rehabilitation of highly degraded calcareous soils of arid regions.