Degraded land: Assessment, impact, restoration, and challenges

Land degradation affects about 120.72 million hectare (Mha) area in India. Water erosion, wind erosion, soil salinity, soil acidity, mining, and waterlogging are the major forms of land degradation. Land degradation leads to reduction in soil quality, biodiversity, ecosystem services, and environmental pollution. Moreover, cultivation of crops under such lands is either impractical or compromised with crop quality. Therefore, the adoption of rehabilitation measures is sine qua-non for restoring soil quality without compromising yield potential. Despite numerous localized studies, significant research gaps persist regarding (i) the comparative assessment of rehabilitation measures across diverse agro-ecological zones, (ii) the quantification of long-term ecological and economic benefits, and (iii) the integration of socio-economic and policy dimensions for large-scale adoption. Addressing these gaps is crucial for designing evidence-based land restoration strategies in India. Accordingly, the objectives of this review are: (1) to assess the current status and extent of land degradation in India; (2) to evaluate the ecological and economic impacts of major degradation types; (3) to synthesize and compare the effectiveness of agronomical, mechanical, agroforestry, and bio-engineering rehabilitation measures; and (4) to identify critical research and policy needs for sustainable land restoration. Findings from published studies reveal that interventions such as sub-surface drainage, agroforestry, shelterbelts, and bench terracing significantly improve soil health, increase cropping intensity and yields, and reduce erosion losses. For example, sub-surface drainage increased cropping intensity by 25-100 %, while agroforestry and bench terracing enhanced SOC and reduced erosion losses by up to 80 %. Therefore, it can be concluded that the implementation of context-specific rehabilitation measures is essential to the restoration of degraded lands and has the capacity to address the problems of livelihood, nutritional, and environmental security. The results of this review will help researchers, land managers, and decision-makers create appropriate strategies for successfully eradicating the issue and comprehend the importance of rehabilitation measures in preventing land degradation to improve ecosystem services in India.