||Ethiopia’s climate smart initiative (CSI) aims to integrate the implications of climate change into Productive Safety Net Programs (PSNP) activities, and systems to strengthen this important social safety net program, and enable Ethiopia to better manage climate risks and help its chronically food insecure population better cope with shocks, create assets and secure livelihoods, even as the climate changes. PSNP’CSI is also tasked with preparing the ground for PSNP’s sustainable public work programs to access climate finance and possibly payments from ecosystem services and benefits to spur and enable the transition towards low-carbon, climate resilient growth and development. More robust and cost effective analysis and information on soil carbon stock changes and associate soil fertility and productivity indicators over space and time is required at multiple stages of development and implementation of PSNP’ participatory integrated watershed management projects to access climate finance and payments for ecosystem services and benefits generated as a result of the implementation of PSNP’s landscape-level climate-smart restorative watershed management interventions in degraded watersheds and agricultural lands. Therefore, the main objectives of this study are to: (i) assemble georeferenced business as usual and project scenario baseline database on soil carbon and other soils fertility, health and productivity indicators for six chronical food insecure and vulnerable Ethiopian regional states (i.e., Afar, Amhara, Oromia, SNNPR, Somali and Tigray), where PSNP’s sustainable agricultural and environmental rehabilitation public works have been implemented widely, ii) evaluate the impacts of Ethiopia’s PSNP participatory integrated watershed intervention projects on soil carbon capture and sequestration, as well as on other climate smart environmental and agricultural co-benefits in light of climate change, food security and low-carbon livelihoods in these regions, (iii) assess low-cost soil carbon and soil fertility measurement techniques for Ethiopia’s PSNP that possess the following important elements, and (iv) support Ethiopia’s safety net climate smart initiative to take advantage of international carbon and climate finance opportunities to support sustaining the existing activities as well as scaling-up future implementations of PSNP participatory watershed public works projects in Ethiopia. Ethiopia’s PSNP CSI soil carbon and fertility assessment developed a robust georeferenced and downscaled national business-as-usual and project scenario baseline database for Ethiopia’s PSNP in selected CSI implementation Woredas of the six Ethiopian regional states using standardized soil analytical measurements. The integrated and multidisciplinary baseline data includes include information about the livelihoods, vegetation, climate, best management practices, time, geospatial aspects of the selected CSI Woredas, in addition to the basic soil carbon and other critical soil biological, physical and chemical characteristics that affect soil fertility and productivity and food security. By integrating this multidisciplinary baseline database with CSI’s aboveground ground biomass resources assessment and geospatial modeling studies, it has been demonstrated that: (i) it is capable of enabling modelling and prediction of soil carbon capture and sequestration, as well as other climate smart environmental and agricultural co-benefits, and (ii) it allow current and future spatial and temporal geospatial mapping, monitoring and reporting, as well as scaling up opportunities. Ethiopia’s PSNP CSI soil carbon and fertility assessment identified the key drivers of soil carbon sequestration and soil fertility in selected PSNP sites, and evaluate their impact on soil carbon capture and sequestration, as well as on other environmental and agricultural co-benefits. The study demonstrated that implantation of PSNP’s restorative landscape-level participatory integrated watershed management interventions in degraded watersheds could be considered as an important strategy for enhancing the soil’s carbon sinking capacity of degraded ecosystems and agricultural lands, and for reducing the rate of enrichment of atmospheric CO2 while having positive impacts on decreasing siltation of waterways and reservoirs, water availability and quality, food security, and on the sustainability environment. Ethiopia’s PSNP CSI soil carbon and fertility assessment also explored MIR-spectroscopy based low-cost soil carbon and fertility co-benefits analytical techniques, as well as of plant growth bioassay-based approached to measure the productivity for Ethiopia’s PSNP. This study demonstrated that MIR-spectroscopy is a non-destructive analytical tool that preserves the integrity of the soil system while analyzing several soil properties simultaneously. Compared to the conventional standardized laboratory techniques-based assessments, it clearly provide a rapid and cost-effective analysis of soil carbon, and other soil chemical and physical characteristics of large number of samples collected from various agricultural, forestry, pastureland and other land use systems. It is appropriate to region, scale and varying landscapes and land use types of Ethiopia’s PSNP. The technique enable rapid but effective assessment, monitoring and reporting of carbon stock changes and other climate smart cobenefits as a result of the implementation of safety net public works projects in food-insecure regions of the country. This makes it very attractive complementary option to Ethiopia’s PSNP to: (i) develop downscaled geospatially-referenced soil-based baseline database, (ii) to conduct fast and reliable broad spatial scale assessment, monitoring and reporting of soil carbon sequestration activities, and (iii) for assessing soil fertility and health, land degradation and other soil-related ecosystem services and co-benefits in PSNP watersheds to understand the soils’ s ability to perform production, environmental and climate related functions, as well as to support the country’s effort to secure climate finance and payments for ecosystem services and benefits generated as a result of the implementation of PSNP’s participatory integrated watershed management projects.