Post-Fire Carbon Dynamics in a UK Woodland: A Case Study from the Roaches Nature Reserve

Nutrient-doped synthetic silicates for enhanced weathering, remineralization and fertilization on agricultural lands of global cold regions- A perspective on the research ahead.

Forest soils play a critical role in the sequestration of atmospheric CO2 and subsequent attenuation of global warming. The nature and properties of organic matter in soils have an influence on the sequestration of carbon. In this study, soils were collected from representative forestlands, including a subtropical evergreen broad-leaved forest (EBF), a coniferous forest (CF), a subalpine dwarf forest (DF), and alpine meadow (AM) along an elevation gradient on Wuyi Mountain, which is located in a subtropical area of southeastern China. These soil samples were analyzed in the laboratory to examine the distribution and speciation of organic carbon (OC) within different size fractions of water-stable soil aggregates, and subsequently to determine effects on carbon sequestration. Soil aggregation rate increased with increasing elevation. Soil aggregation rate, rather than soil temperature, moisture or clay content, showed the strongest correlation with OC in bulk soil, indicating soil structure was the critical factor in carbon sequestration of Wuyi Mountain. The content of coarse particulate organic matter fraction, rather than the silt and clay particles, represented OC stock in bulk soil and different soil aggregate fractions. With increasing soil aggregation rate, more carbon was accumulated within the macroaggregates, particularly within the coarse particulate organic matter fraction (250–2000 μm), rather than within the microaggregates (53–250μm) or silt and clay particles (< 53μm). In consideration of the high instability of macroaggregates and the liability of SOC within them, further research is needed to verify whether highly-aggregated soils at higher altitudes are more likely to lose SOC under warmer conditions.

Digital soil mapping of soil organic carbon stocks under different land use and land cover types in montane ecosystems, Eastern Himalayas

Enrichment of soil organic carbon (SOC) stocks through sequestration of atmospheric CO 2 in agricultural soils is important because of its impacts on soil quality, agronomic production, and adaptation to and mitigation of climate change. In a 21‐yr field experiment conducted under subhumid tropical conditions in India, the impacts of crop residue C inputs were assessed for the rice ( Oryza sativa L.)–lentil ( Lens esculenta Moench) cropping sequence. These impacts were evaluated in an experiment involving mineral fertilizers and manuring treatments on crop yield sustainability with reference to critical biomass requirements for maintenance of SOC in an Inceptisol. Application of farmyard manure (FYM) without and with mineral fertilizers increased C input and SOC concentration and stock. In comparison with the control, the 100% organic (FYM) treatment had significantly higher profile SOC (27.5 Mg ha −1 ), and more C build up (55.0%) and C sequestration (6.6 Mg C ha −1 ) to 1‐m depth vis‐à‐vis the antecedent values in 1986. These parameters were also higher in 100% FYM treatment at a rate providing equivalent amount of the recommended dose of N followed by conjunctive use of FYM and mineral fertilizers. The SOC stock and rate of sequestration were positively correlated with cumulative C input, and with sustainable yield index (SYI) of upland rice and lentil. Higher grain yield (1.95 and 1.04 Mg ha −1 of rice and lentil, respectively) was obtained with the application of 50% organic (FYM)+50% recommended dose of fertilizer (RDF). In comparison, higher SOC sequestration rate was measured with the application of 100% organic (FYM). For every Mg increase in SOC stock in the root zone there was 0.16 and 0.18 Mg ha −1 yr −1 yield increase of rice and lentil, respectively. For maintaining a stable SOC level (zero change due to cropping), a minimum quantity of 2.47 Mg C ha −1 yr −1 is required for this soil, climate, cropping system, and fertilization treatments. To achieve this quantity of C, 7.1 Mg of biomass is required to be produced every year vs. average rice and lentil yields of 1.6 and 0.7 Mg ha −1 , respectively. The sole application of mineral fertilizers at 50 or 100% of the RDF did not maintain the SOC stock. Thus, application of FYM (or other organics) in conjunction with mineral fertilizers is essential to maintaining and enhancing the SOC stock in the rice‐based cropping systems.

The sequestration of atmospheric CO₂ in soil is suggested as an effective climate change mitigation strategy. Biochar application shows promise in this regard, while the role of fungi in soil carbon cycling and sequestration is also under investigation. Using a novel high-throughput plant phenomics approach, we explore the impact of arbuscular mycorrhizal fungi (AMF) inoculation and biochar application on wheat growth and soil carbon, guided by one of the leading global carbon credit schemes. Wheat was successfully colonised by AMF, achieving an average root length colonisation of 35.9%. We uncover an indirect fungal-mediated pathway to soil carbon sequestration, with mycorrhizal plants generating more biomass across all soil treatments without yield penalties, suggesting colonised plants deliver more plant derived carbon to the soil, potentially leading to long-term soil carbon gains. Conversely, fungal-driven carbon loss occurred, significantly reducing soil carbon accumulation in unamended soil, but not in biochar-amended soil, suggesting that biochar moderates fungal activity and positively impacts the soil carbon balance. While both biochar and AMF enhance plant growth, their direct effects on soil carbon are complex. Although biochar did not significantly increase soil carbon stocks beyond its own contribution, its ability to regulate fungal activity could play an important role in influencing soil carbon sequestration.

Soil inorganic carbon, the other and equally important soil carbon pool: Distribution, controlling factors, and the impact of climate change

As a principal part of the atmosphere–lithosphere interface, soil plays a key role in regulating the atmospheric CO2 concentration and global climate. Comprising two major pools (carbonate in soils and bicarbonate in groundwater), soil inorganic carbon (SIC) is deemed as the primary carbon (C) sink and source in areas with low mean annual rainfall. SIC may originate from soil parent material or from the formation of secondary carbonate when divalent cations from an extraneous source are supplied. The latter may result in pedogenic carbonate (PC) formation, increasing soil C content and sequestering atmospheric carbon. Since the sequestration of atmospheric CO2 through formation of pedogenic carbonate is gaining popularity as a method to support climate change mitigation efforts and to claim carbon credits, the mechanisms influencing the formation and migration of pedogenic carbonate need to be well understood. The present review provides an overview of the available literature on potential natural and anthropogenic factors influencing the pedogenic carbonate pool in soils. Firstly, the overall mechanisms of pedogenic carbonate formation, as well as the control factors, are described. Secondly, the impact of various land-use changes on pedogenic carbon pool modification is discussed. Then, the potential of stabilizing atmospheric CO2 through PC formation and the challenges and techniques of tracking the formation of PC through engineered pathways in soils are explored. Finally, isotopic signature as a technique for distinguishing neo-formed carbonate in soil is scrutinized.

Enrichment of soil organic carbon (SOC) stocks through sequestration of atmospheric CO2 in agricultural soils is important because of its impacts on adaptation to and mitigation of climate change while also improving crop productivity and sustainability. In a long‐term fertility experiment carried out over 27 y under semiarid climatic condition, we evaluated the impact of crop‐residue C inputs through rainfed fingermillet (Eleusine coracana [L.] Gaertn.) cropping, fertilization, and manuring on crop yield sustainability and SOC sequestration in a Alfisol soil profile up to a depth of 1 m and also derived the critical value of C inputs for maintenance of SOC. Five treatments, viz., control, farmyard manure (FYM) 10 Mg ha–1, recommended dose of NPK (50 : 50 : 25 kg N, P2O5, K2O ha–1), FYM 10 Mg ha–1 + 50% recommended dose of NPK, and FYM 10 Mg ha–1 + 100% recommended dose of NPK imposed in a randomized block design replicated four times. Application of FYM alone or together with mineral fertilizer resulted in a higher C input and consequently built up a higher C stock. After 27 y, higher profile SOC stock (85.7 Mg ha–1), C build up (35.0%), and C sequestration (15.4 Mg C ha–1) was observed with the application of 10 Mg FYM ha–1 along with recommended dose of mineral fertilizer and these were positively correlated with cumulative C input and well reflected in sustainable yield index (SYI). For sustenance of SOC level (zero change due to cropping) a minimum quantity of 1.13 Mg C is required to be added per hectare per annum as inputs. While the control lost C, the application of mineral fertilizer served to maintain the priori C stock. Thus, the application of FYM increased the C stock, an effect which was even enhanced by additional amendment of mineral fertilizer. We conclude that organic amendments contribute to C sequestration counteracting climate change and at the same time improve soil fertility in the semiarid regions of India resulting in higher and more stable yields.

Soil organic carbon (SOC) is a cornerstone of global carbon cycling, ecosystem health, and climate regulation. However, accurately predicting SOC storage (SOCS) and its sequestration potential under varying climatic scenarios remains a major challenge, particularly in high-altitude, climate-sensitive regions like the Qinghai-Tibet Plateau. Grasslands and croplands in this region are pivotal for carbon management, yet their dynamics remain insufficiently understood. This study addresses two core scientific questions: (1) How can SOCS dynamics be modeled accurately across large spatial scales and diverse ecosystems under future climate scenarios? (2) How to comprehensively evaluate potential of SOC sequestration and effectively guide development of targeted carbon management strategies?Andriolo, Mary and Gu&amp;#233;rif developed a simple first-order kinetic model that relies on key controlling input data, which is ideal for application across large spatial and long temporal scales. This study improved the traditional AMG model by using NPP as the core carbon input indicator, replacing the traditional crop harvest index (HI), which is more suitable for grassland ecosystems. In addition, the model dynamically adjusted the carbon mineralization rate parameter &amp;#119896; to reflect the effects of temperature, precipitation and soil properties on SOC dynamics. The improved AMG model (I-AMG) generates time series data as input variables for random forest (RF) model by simulating the SOC dynamics of grassland and cropland. We further combine historical SOCS and environmental variables such as terrain and vegetation indices for training and prediction. The RF-AMG integrated model combines the process simulation capability of I-AMG model with nonlinear fitting capability of&amp;#160; RF algorithm, which can capture complex environmental variable interaction effects and significantly improve prediction accuracy.We used the global SOC content data provided by the Harmonized World Soil Database (HWSD) in 1980 to estimate the baseline SOCS at a resolution of 1km. The SOCS data in 2020 was provided by the National Qinghai Tibet Plateau Science Data Center using a grid dataset of soil carbon pools created through field surveys and machine learning, and was used as an observation to evaluate the simulation prediction accuracy of our improved AMG model. Meanwhile, we predicted the SOCS of cropland and grassland in Qinghai Province over the next 40 years under mild (RCP4.5) and extreme (RCP8.5) climate scenarios. And further proposed a four-quadrant method to evaluate the energy storage potential of SOC, dividing the carbon sequestration potential level of Qinghai Province in the next 40 years into four different categories based on SOC saturation deficit and change rate. This method identifies the spatial characteristics of SOC sequestration potential in Qinghai over next 40 years, which can help decision-makers gain a detailed understanding of regions with different carbon management priorities.This study demonstrates the strength of combining process-based modeling with machine learning to address complex environmental challenges. This novel framework can be used for assessing soil carbon sequestration potential of natural ecosystems, and practical guidance for policymakers to develop tailored strategies for soil conservation, sustainable agriculture and ecosystem restoration. These efforts support global carbon neutrality goals and provide valuable insights into climate-smart land management practices.

Soil microbial attributes along a chronosequence of Scots pine (Pinus sylvestris var. mongolica) plantations in northern China

Srinivasarao, Ch., Venkateswarlu, B., Lal, R., Singh, A. K., Kundu, S., Vittal, K. P. R., Sharma, S. K., Sharma, R. A., Jain, M. P. and Chary, G. R. 2012. Sustaining agronomic productivity and quality of a Vertisolic Soil (Vertisol) under soybean-safflower cropping system in semi-arid central India. Can. J. Soil Sci. 92: 771–785. Enrichment of soil organic carbon (SOC) stocks through sequestration of atmospheric CO2 in agricultural soils is important because of its impacts on improving soil quality and agronomic production, and also for adaptation to and mitigation of climate change. Thus, a 15-yr soil fertility management experiment was conducted in the semi-arid tropical region of central India to evaluate the impact of crop residue C input on soybean (Glycine max L.)–safflower (Carthamus tinctorius L.) cropping sequence and SOC sequestration in soils of Vertisolic order (Vertisols). Retention of crop residues of soybean/safflower, and application of farmyard manure (FYM) at 6 Mg (t) ha−1 alone or in co...

Spatial responses of soil carbon stocks, total nitrogen, and microbial indices to post-wildfire in the Mediterranean red pine forest

Soil, a natural four‐dimensional body at the atmosphere–lithosphere interface, is organic‐carbon‐mediated realm in which solid, liquid, and gaseous phases interact at a range of scales and generate numerous ecosystem goods and services. Soil organic carbon (SOC) strongly impacts soil quality, functionality and health. Terms soil quality and soil health should not be used interchangeable. Soil quality is related to what it does (functions), whereas soil health treats soil as a living biological entity that affects plant health. Through plant growth, soil health is also connected with the health of animals, humans, and ecosystems within its domain. Through supply of macro‐ and micronutrients, soil health, mediated bySOCdynamics is a strong determinant of global food and nutritional security. Soil C pool consists of two related but distinct components:SOCand soil inorganic C (SIC). TheSICpool comprises of primary and secondary carbonates, and the latter consists of calcitic (no net sequestration of atmosphericCO2) and silicatic (net sequestration). WhileSOCis highly dynamic, its mean residence time depends on the degree of protection (physical, chemical, biological, and ecological) within the soil matrix. Formation of stable microaggregates and of organo–mineral complexes can protectSOCagainst microbial processes for millennia. In addition to formation of silicatic type of secondary carbonates, leaching of bicarbonates into the subsoil or shallow water table is also an important mechanism of sequestration ofCO2asSIC. Numerous soil functions and ecosystem services depend onSOCand its dynamics. Improvements in soil health, along with increase in availability of water and nutrients, increases soil's resilience against extreme climate events (e.g., drought, heat wave) and imparts disease‐suppressive attributes. Enhancing and sustaining soil health is also pertinent to advancing Sustainable Development Goals of the U.N. such as alleviating poverty, reducing hunger, improving health, and promoting economic development.

Potential role of giant marine diatoms in sequestration of atmospheric CO2 during the Last Glacial Maximum: δ13C evidence from laminated Ethmodiscus rex mats in tropical West Pacific

Effects of fire severity and pre-fire stand treatment on plant community recovery after a large wildfire