The publication highlights of this week pertain to a variety of CDR methods such as enhanced rock weathering, marine CDR, forestation and soil carbon sequestration.
Combining Organic Amendments with Enhanced Rock Weathering Shifts Soil Carbon Storage in Croplands
Abstract
Enhanced rock weathering (ERW) involves applying crushed silicate minerals to cropland soils to remove carbon dioxide and stabilize the global climate. If practiced widely, ERW has the potential to mitigate climate change and improve soil health and crop productivity. However, most ERW studies emphasize inorganic carbon (IC) chemistry, using model-based estimates and short-term mesocosms. Limited field data exist on how ERW interacts with organic amendments to affect organic carbon (C) cycling in soils. In a three-year field study in conventionally managed, irrigated maize fields, we monitored how key soil variables responded to crushed rock-alone, and in combination with compost and/or biochar. We measured weathering indicators (pH, major cations, and IC contents) and organic fractions, including particulate organic matter (POM), mineral-associated organic matter (MAOM), microbial biomass C, and water-extractable organic C. Rock-alone treatments increased weathering proxies (pH and IC) and showed an increasing trend in POM and MAOM, relative to control. In contrast, combining crushed rock with organic amendments resulted in lower soil organic C and nitrogen (N) concentrations (in both POM and MAOM) compared to organic amendments alone, though IC increased in the rock+compost treatment. Combining rock with both compost and biochar (compost/biochar) significantly lowered MAOM-N compared to compost/biochar alone. Overall, co-applying rock with organic inputs may promote weathering and C accrual but slow the accrual rate of organic C and N relative to organic amendments alone. Quantifying these trade-offs over multiple years and scales is critical to integrating ERW with existing soil health practices and climate mitigation strategies.
Sohng, J. et al. (2025) Combining Organic Amendments with Enhanced Rock Weathering Shifts Soil Carbon Storage in Croplands 998 (180179) Science of the Total Environment.
Read the full paper here: Combining Organic Amendments with Enhanced Rock Weathering Shifts Soil Carbon Storage in Croplands I Science of the Total Environment.
Exploring Site-Specific Carbon Dioxide Removal Options with Storage or Sequestration in the Marine Environment - The 10 Mt CO2 yr-1 Removal Challenge for Germany
Abstract
Marine carbon dioxide removal (mCDR) and geological carbon storage in the marine environment (mCS) promise to help mitigate global climate change alongside drastic emission reductions. However, the implementable potential of mCDR and mCS depends, apart from technology readiness, also on site-specific conditions. In this work, we explore different options for mCDR and mCS, using the German context as a case study. We challenge each option to remove 10 Mt CO2 yr−1, accounting for 8%–22% of projected hard-to-abate and residual emissions of Germany in 2045. We focus on the environmental, resource, and infrastructure requirements of individual mCDR and mCS options at specific sites, within the German jurisdiction when possible. This serves as an entry point to discuss main uncertainty factors and research needs beyond technology readiness, and, where possible, cost estimates, expected environmental effects, and monitoring approaches. In total, we describe 10 mCDR and mCS options; four aim at enhancing the chemical carbon uptake of the ocean through alkalinity enhancement, four aim at enhancing blue carbon ecosystems’ sink capacity, and two employ geological off-shore storage. Our results indicate that five out of 10 options would potentially be implementable within German jurisdiction, and three of them could potentially meet the challenge. Our exercise serves as an example on how the creation of more tangible and site-specific CDR options can provide a basis for the assessment of socio-economic, ethical, political, and legal aspects for such implementations. The approach presented here can easily be applied to other regional or national CDR capacity considerations.
Yao, W. et al. (2025) Exploring Site-Specific Carbon Dioxide Removal Options with Storage or Sequestration in the Marine Environment - The 10 Mt CO2 yr-1 Removal Challenge for Germany 13 (4) Earth’s Future.
Read the full paper here: Exploring Site-Specific Carbon Dioxide Removal Options with Storage or Sequestration in the Marine Environment - The 10 Mt CO2 yr-1 Removal Challenge for Germany I Earth’s Future.
Carbon Emissions from Forest Harvest and Fire Offset Approximately Half of Carbon Sequestration of Forestation in China during 1986-2020
Abstract
Forest activities and fire disturbance (FAFD) play an important role in the global carbon cycle. Although many studies have been explored to examine the individual effect of forestation, forest harvest, and forest fire on the carbon cycle in China, their combined impacts remain unclear. Moreover, rare research has been examined the impacts of these activities at the species level on the net carbon budget. By integrating remotely sensed, detailed tree species and statistical data into a spatialized modeling approach, we estimated the carbon budget from three major FAFD (i.e., forestation, forest harvest and forest fire) in China during 1986-2020. We found that FAFD overall showed net carbon sequestration of total -710.64±136.4 Tg C with sequestration of -1529.36 ± 202.59 Tg C from forestation and emission of 585.38 ± 29.91 Tg C from forest harvest and 233.34 ± 36.28 Tg C from fire. Spatially, the national average carbon sequestration density from FAFD was -172.95 Mg C km-2, with notable regional variations. Carbon emissions from forest harvest and fire offset 53.52% (38.26% and 15.26%, respectively) of carbon sequestration from forestation. More than 90% of tree species exhibited net carbon sequestration from forestation and harvest. The national offset impact of forest harvest varied by tree species, ranging from 3.51% to 101.27%. Owing to high carbon emission from forest harvest, Quercus and Eucalyptus showed large offset effects over 97%. In contrast, Pinus tabulae formis and Larix demonstrated small offset effects of only 3.51% and 10.23% due to high carbon sequestration. These findings highlight the importance of accounting for carbon emissions from deforestation and forest fire when aiming to maximize carbon sequestration through forestation.
Mai, J. (2025) Carbon Emissions from Forest Harvest and Fire Offset Approximately Half of Carbon Sequestration of Forestation in China during 1986-2020 375 (110830) Agricultural and Forest Meteorology.
Read the full paper here: Carbon Emissions from Forest Harvest and Fire Offset Approximately Half of Carbon Sequestration of Forestation in China during 1986-2020 I Agricultural and Forest Meteorology.
Divergent Responses of Carbon and Nitrogen Functional Genes Composition to Enhanced Rock Weathering
Abstract
Enhanced rock weathering (ERW) is a scalable strategy for atmospheric carbon dioxide removal. The microbiome function critically regulates the below-ground cycle of carbon and nitrogen in terrestrial ecosystems. However, microbial functioning related to carbon and nitrogen under ERW remains elusive. Here we investigated how wollastonite addition affects key microbial carbon and nitrogen-cycles genes investigated using metagenomic, in a tropic rubber plantation. After two-year, ERW had enhanced the alpha diversity of biogeochemical cycling genes was mainly driven by increased soil pH. ERW led to an increase in the relative abundance of carbon-fixation genes, and a decrease in the carbon-degradation genes, providing microbiological evidence for carbon dioxide emissions. Additionally, the relative abundance of nitrogen-cycling functional genes, and available iron increased after wollastonite addition, indicating ERW may influence nitrous oxide emissions through biological and chemical processes. Altogether, our results illustrate how the effect of ERW alters microbial functioning, impacting soil organic matter dynamics.
Chen, Q. et al. (2025) Divergent Responses of Carbon and Nitrogen Functional Genes Composition to Enhanced Rock Weathering 6 (645) Communications Earth & Environment.
Read the full paper here: Divergent Responses of Carbon and Nitrogen Functional Genes Composition to Enhanced Rock Weathering I Communications Earth & Environment.
Mechanic Insights into Farmland Soil Carbon Sequestration: A Review of Substituting Green Manure for Nitrogen Fertilizer
Abstract
Sustainable agricultural intensification requires innovative approaches to simultaneously enhance productivity and mitigate environmental impacts—a challenge critical to global food security and climate change mitigation. The traditional fertilization system, with a single application of nitrogen fertilizer, while effective for crop yields, often leads to soil organic carbon (SOC) depletion, whereas green manure systems offer a dual benefit of nitrogen supply and SOC sequestration potential. However, the mechanisms by which green manure substitution enhances soil carbon sequestration (SCS) remain systematically underexplored in comparison to chemical fertilization. This review systematically examines (1) the mechanisms underlying SOC sequestration, (2) SOC losses associated with traditional fertilization practices, and (3) the theoretical foundation and practical applications of green manure as a nitrogen fertilizer substitute. We provide an in-depth analysis of the mechanisms through which green manure substitution drives SCS. Furthermore, we identify three critical areas for future investigation: (i) optimization of green manure management strategies to enhance SCS efficiency; (ii) comprehensive assessment of green manure’s ecological benefits through long-term, multi-scale studies; and (iii) evaluation of green manure’s climate change adaptation capacity and carbon sequestration potential across diverse climatic scenarios. These findings fundamentally advance our understanding of green manure’s role in sustainable agriculture by establishing its dual function as both a nitrogen source and carbon sequestration driver. In addition, these insights have immediate relevance for agricultural policy and practice, particularly in regions where soil health and carbon storage are prioritized alongside crop yield.
Wang, P. et al. (2025) Mechanic Insights into Farmland Soil Carbon Sequestration: A Review of Substituting Green Manure for Nitrogen Fertilizer 15 (5) Agronomy.
Read the full paper here: Mechanic Insights into Farmland Soil Carbon Sequestration: A Review of Substituting Green Manure for Nitrogen Fertilizer I Agronomy.