Tree-based Systems for Enhancing Environmental Services of Saline Environments

Abstract

Nearly one billion hectares of arid and semiarid regions of the world are salt-affected. In India, saline and sodic soils occupy an area of about 6.75 Mha. Salt-affected lands can be utilized for producing food, fodder, timber, and fuelwood by incorporating trees with crops and forage grasses. Biodrainage has been successfully used to control the problem of waterlogging and salinity in irrigated areas. The tree-based systems for salt-affected lands include agri-silvicultural, silvopastoral agroforestry, fruit-based agroforestry systems, and trees for biodrainage, energy plantations, and agroforestry for dryland salinity. The tree-based systems have been found to improve the provisioning, supporting, and regulatory services. The provisioning services include genetic resources, food, energy, timber, fodder, and fresh water. The ability of soils to deliver the ecosystem services directly depends on soil regulatory services of soil biodiversity, decomposition, regulation of fluxes of greenhouse gases, and plant-soil nutrient cycles. Biodrainage is one of the important ecosystem services that could be provided by tree-based systems in saline and waterlogged soils. Agroforestry on salt lands provides environmental benefits like increase in biodiversity, salinity mitigation, biodrainage, and pollination in addition to carbon sequestration. Salt-affected soils have the potential to sequester carbon in the soil-plant system. In the southern Murray-Darling basin region of South Australia, carbon sequestration in plant biomass has been found to be significant, and the values ranged from 6.3 to 10.6 CO2-e Mg ha−1 yr−1. Soil carbon sequestration in different biosaline agroforestry systems in India is estimated to be 99.33–35.28 CO2-e Mg ha−1. This chapter presents an overview of environmental services of tree-based systems on saline, sodic, and waterlogged soils with special reference to carbon sequestration as a regulating ecosystem service and the role of agroforestry in soil bioamelioration as well as climate change mitigation.