Intelligent Approaches to Analysing the Importance of Land Use Management in Soil Carbon Stock in a Semiarid Ecosystem, West of Iran

<p>Accurately representing historical soil and vegetation carbon stocks in land data systems is important when evaluating outcomes of land use change decisions (e.g. land use change emissions). Moreover, carbon stocks (especially soil carbon stocks) are subject to uncertainty and vary significantly based on assumptions used by different data sets. For this reason, when representing carbon stocks in data systems, it is important to present a range of values based on the distribution of carbon stock observations for a given unit (region/country/basin) at the grid cell level.</p><p>We updated the moirai land data system (LDS) to generate historical estimates of soil carbon stocks (at a depth of 0-30 cms) and vegetation carbon stocks (broken down into above ground and below ground biomass) at the sub-national (basin) level based on global fine resolution raster input data. The LDS has also been programmed to calculate soil carbon stock values based on multiple data sets (such as SoilGrids database maintained by the ISRIC and the harmonized world soil database maintained by the FAO) to enable efficient comparisons of carbon stock estimates by end users between data sets. Moreover, to account for uncertainty, carbon stocks are calculated for 6 “states” based on 5 arcmin grid cell level observations of carbon stocks (The states are -weighted average, median, minimum, maximum, quartile 1 and quartile 3).  This provides a robust representation of soil and vegetation carbon stocks at the sub-national level which are differentiated by data sources and the above-mentioned states, which can be used to represent more realistic outcomes from land use change decisions. To demonstrate the utility of this data, we also implemented the same in the land module of a multi sector dynamics model, Global Change Analysis Model (GCAM) to observe the impacts on land use change decision outcomes with different initializations of carbon stock data.   </p>

Research Highlights: The estimation of soil and litter carbon stocks by the Land Use, Land-Use Changes, and Forestry (LULUCF) sectors has the potential to improve reports on national greenhouse gas (GHG) inventories. Background and Objectives: Forests are carbon sinks in the LULUCF sectors and therefore can be a comparatively cost-effective means and method of GHG mitigation. Materials and Methods: This study was conducted to assess soil at 0–30 cm and litter carbon stocks using the National Forest Inventory (NFI) data and random forest (RF) models, mapping their carbon stocks. The three main types of forest in South Kora were studied, namely, coniferous, deciduous, and mixed. Results: The litter carbon stocks (t C ha−1) were 4.63 ± 0.18 for coniferous, 3.98 ± 0.15 for mixed, and 3.28 ± 0.13 for deciduous. The soil carbon stocks (t C ha−1) were 44.11 ± 1.54 for deciduous, 35.75 ± 1.60 for mixed, and 33.96 ± 1.62 for coniferous. Coniferous forests had higher litter carbon stocks while deciduous forests contained higher soil carbon stocks. The carbon storage in the soil and litter layer increased as the forest grew older; however, a significant difference was found in several age classes. For mapping the soil and litter carbon stocks, we used four random forest models, namely RF1 to RF4, and the best performing model was RF2 (root mean square error (RMSE) (t C ha−1) = 1.67 in soil carbon stocks, 1.49 in soil and litter carbon stocks). Our study indicated that elevation, accessibility class, slope, diameter at breast height, height, and growing stock are important predictors of carbon stock. Soil and litter carbon stock maps were produced using the RF2 models. Almost all prediction values were appropriated to soil and litter carbon stocks. Conclusions: Estimating and mapping the carbon stocks in the soil and litter layer using the NFI data and random forest models could be used in future national GHG inventory reports. Additionally, the data and models can estimate all carbon pools to achieve an accurate and complete national GHG inventory report.

Forest ecosystems are recognised as Natural Climate Solutions because forest soils are such important carbon stores, containing almost half of the total soil organic carbon of terrestrial ecosystems. Here we present the results of a synthesis of soil carbon stocks by World Reference Base soil group, and forest litter carbon stocks for afforested soils in the Republic of Ireland. We report soil carbon stocks of mineral soils separately from organo-mineral soils. We estimated mean soil carbon stocks in a 100 cm deep mineral soil to be between 162 ± 87 t C/ha (Gleysols) and 416 ± 0 t C/ha (Umbrisols, n = 1), and between 173 ± 65 t C/ha (Phaeozems) and 602 ± 226 t C/ha (Regosols) in a 100 cm deep organo-mineral soil; both less than the estimated soil carbon stocks in organic soils (Histosols): 645 ± 222 t C/ha. The entire soil carbon stocks in mineral Leptosols (100 ± 0 t C/ha, n = 1), Stagnosols (144 ± 39 t C/ha), Luvisols (159 ± 52 t C/ha) and Fluvisols (231 ± 0 t C/ha, n = 1) was contained in the upper 50 cm of soil. Based on a 100 cm deep soil, Histosols hold 1.6–4 times the amount of soil C than mineral soils and 1.1–3.7 times the amount in organo-mineral soils for the same profile depth. Certain mineral (e.g. Umbrisols) and organo-mineral soils (e.g Gleysols, Regosols) contain substantial soil carbon stocks relative to Histosols. We found considerable soil carbon stocks below 30 cm depth, which highlights the importance of depth extent for cumulative soil carbon stocks estimates. The upper third of the 100 cm profile contained 33% (Histosols) to 70% (Luvisols) of the soil carbon stocks and the upper half of a 100 cm profile contained the entire soil carbon stocks for Leptosols, Stagnosols, Luvisols and Fluvisols and organo-mineral Leptosols. Unfortunately, there were few samples available for mineral Leptosols, Umbrisols, Luvisols and Fluvisols, and the organo-mineral Stagnosols and Regosols, which precludes the drawing of conclusions for these groups. Relative to the soil carbon stocks, we found low mean forest litter stocks: 4.1 ± 5.5 t C/ha, 4.8 ± 3.3 t C/ha and 2.7 ± 2.9 t C/ha for broadleaf, coniferous and mixed forests respectively. Few exceptions existed for individual sites: 22.7 and 131.3 t C/ha for broadleaf forests. Our results are evidence that soil carbon stocks in mineral, organo-mineral and organic soils need to be protected, appropriately managed, and enhanced to be beneficial for greenhouse gas mitigation. Assessments are needed to identify which soil-site-management practice combinations risk soil carbon stock depletion. The large range observed in soil and litter carbon stocks stresses the importance of adequately accounting for soil group differences when GHG inventories are compiled. The synthesised dataset will contribute to improved SCS estimation for afforested lands in Ireland.

Forests form a major organic carbon reservoir, both above- and belowground. In the course of global change, predicting possible changes in these carbon reservoirs is essential. To this end, the Horizon Europe PathFinder project aims to develop an innovative forest monitoring system allowing consistent EU greenhouse gas reporting of LULUCF (Land Use, Land Use Change & Forestry) in combination with advanced policy pathway assessments. Greenhouse gas reporting of soil organic carbon (SOC) stock changes in forests commonly relies on simulations by soil carbon cycling models, such as Yasso (Y20), which uses only climate data and soil carbon inputs that can be derived by country-specific approaches from National Forest Inventories. However, the agreement between measured versus simulated carbon stocks and changes at the European scale has not yet been established. Within the framework of this project, this study aims to derive European-wide harmonised soil carbon inputs and stock estimates since the 1990s and further develop the current estimation methodology. After exploration of the available data sets, the ICP Forests Level II forest condition monitoring database was found the most suitable to set the initial modelling conditions. It is the only harmonised data set at the European scale that comprises above- and belowground compartments and contains repeated assessments on a subset of about 200 plots across Europe. The pre-processing of the observed data on soil carbon stock, growth and litterfall from the central ICP Forests database was very labour-intensive. As part of the ICP Forests monitoring programme, carbon concentrations and bulk densities are measured down to a depth of 80 cm. Using mass-preserving splines, soil carbon stocks were estimated down to a depth of 100 m to make them comparable with Y20. Regression models were developed to estimate litterfall inputs based on forest inventory data. We simulated SOC stocks by Y20 in ICP Forests Level II plots with available stand inventory data and soil characterization. Soil carbon inputs were obtained using two approaches: an inventory approach, with litterfall estimated by the above-mentioned regression models, and root and coarse-woody inputs by allometric functions, and a satellite approach, with net primary production (NPP) from MODIS at 500 m resolution. The Y20-simulated SOC stocks were compared with the SOC stocks to 100 cm depth based on the soil inventory data. an inventory approach, with litterfall estimated by the above-mentioned regression models, and root and coarse-woody inputs by allometric functions, and a satellite approach, with net primary production (NPP) from MODIS at 500 m resolution. The Y20-simulated SOC stocks were compared with the SOC stocks to 100 cm depth based on the soil inventory data. On average, the satellite approach estimated higher soil carbon inputs than the inventory approach (+20%). The SOC stocks simulated by Y20 were overall in line with observed SOC stocks. The simulations for broadleaf-dominated stands agreed well with SOC measurements, with average deviations below 1 kg C m-2 using the satellite approach. In coniferous stands, Y20-simulated SOC stocks were lower than observed by 3-5 kg C m-2. This is likely due to the intrinsic soil properties driving SOC storage and stabilization in highly acidic, coniferous forests (i.e. Podzols and Umbrisols), which are not accounted for in Y20.

Carbon Sequestration in Soils of Latin America

Soil is the largest terrestrial carbon pool and has been increasingly recognized to play crucial role to mitigate global warming resulting from climate change and land use and land cover change. The carbon cycle is closely linked with nitrogen cycles and needs to be studied together for their important implications for mitigating land degradations and associated declining productivity. Within the global biodiversity hotspot ofHimalayas, which constitutes more than one third of India's carbon pool, the Eastern Himalayas in spite of having highest forest cover, protected area network coverage, biodiversity, and endemicity have been understudied for soil carbon and nitrogen dynamics. The present study was designed to assess the patterns and determinants of soil carbon stock, SOC stocks, nitrogen stocks, and carbon/nitrogen (C:N) ratio along the altitudinal gradient, forest type, and depth in Darjeeling Himalayas, India. We followed standard protocol for soil sampling and analysis. The soil carbon stocks (257.02 to 527.79MgCha-1), SOC stocks (152.55 to 398.88MgCha-1), and soil nitrogen stocks (15.10 to 32.38MgNha-1) increased (but C:N ratio 15.13 to 19.12 declined) along the altitudinal gradient (154 to 3170m), forest types (tropical moist deciduous forest: MWLS < East Himalayan temperate forest: NVNP < East Himalayan sub-alpine forest: SNP) and annually (year 1 < year 2); however, opposite pattern was observed with increase in depths. The soil carbon stocks, SOC stocks, soil nitrogen stocks, and C:N ratio showed strong effects of forest type, depth, elevation, NDVI, bulk density, MI, and AET. Additionally, there was strong relationship of MAP with soil carbon stock and SOC stock, MAT with C:N ratio, and year of sampling with SOC stocks and C:N ratio. The soil carbon stocks, SOC stocks, and soil nitrogen stocks showed negative correlation with different environmental factors (MAT, MAP, NDVI, MI, AET), but positive correlation with elevation, however, C:N ratio had weakpositive correlation. We conclude that the different forests types of Darjeeling Himalayas encompassing wide elevation gradient have high levels of soil carbon stocks, SOC stocks, soil nitrogen stocks, and C:N ratio, and hence must be properly managed to maximize their soil carbon sequestration potential.

Estimation of carbon sequestration in the forest sector should take into consideration changes in carbon stock in all carbon pools, including above-ground and below-ground biomass, litter, deadwood and soil. In this review, we discuss current knowledge of carbon stocks in litter, deadwood and soil in Japan’s forest sector. According to data from published reports and nationwide surveys, the carbon stock in forest litter is less than that indicated in the Intergovernmental Panel on Climate Change (IPCC) guidelines for temperate and cool temperate forests; for example, coniferous species showed 4.4 Mg C ha−1 for Cryptomeria japonica and 3.1 Mg C ha−1 for Chamaecyparis obtusa, and broad-leaved species ranged from 3.5 Mg C ha−1 for Castanopsis spp. to 7.3 Mg C ha−1 for Fagus spp. For deadwood carbon stock, coniferous plantations with a record of non-commercial thinning showed 17.1 Mg C ha−1 and semi-natural broad-leaved forests showed 5.3 Mg C ha−1 on average, although only limited data were available. The black soil group (comparable to Andosols and Andisols) showed large carbon stocks in soil layers 0–30 cm deep (130 Mg C ha−1). The brown forest soil group (Cambisols and Inceptisols), occupying the most dominant area, showed a carbon stock of 87.0 Mg C ha−1 on average, which was similar to the data shown in the IPCC guidelines. In a comparison of land use between the forest sector and the agricultural sector for the same soil group, the carbon stock in the agricultural soil was 21% lower and in the grassland soil it was 18% higher than the stock in the forest soil. In this review, we also discuss issues for improving the estimation method and inventory of carbon stock in litter, deadwood and soil in Japan.

Whilst it is generally understood that grasslands are able to store significant amounts of carbon and that much of our degraded agricultural soil has capacity to build carbon stocks and potentially mitigate on-farm emissions, to date, the greater focus of studies has been on the response of lowland grassland soil carbon to management practices. In contrast, comprehension of current and potential soil carbon stocks in heterogeneric &amp;#8216;upland&amp;#8217; or marginal farmed environments is currently lacking, and the potential for sustainable livestock production to deliver increased soil carbon sequestration unsubstantiated. With upland farming systems producing 29% and 44% of breeding cows and sheep respectively, understanding the impact of changes in upland livestock management on soil carbon is critical to ensure future land management scenarios are environmentally positive and can sustain food production.We aim to address this knowledge gap by combining field surveys of soil carbon concentrations and stocks with modelling of potential soil carbon change under nutrient, land use and climate change scenarios using the process-based N14CP model. In this contribution we will present the empirical data and carbon modelling results.Three 'upland' livestock farms in Cumbria, UK were chosen as representative of diversity of parent material, climate, topography and livestock farming practices. Pedogenic-stratified random sampling of the top 0 &amp;#8211; 30cm soil at a rate of 1 sample per 2 hectares; &amp;#8805;5 metres apart was conducted July-September 2024. Samples were assessed for bulk density (corrected for coarse fragments &amp;#8805;2mm) and carbon concentration (by dry combustion).Preliminary analyses suggest high spatial variation in bulk density, soil carbon concentration and stocks within and between farms, reflecting the heterogeneity of &amp;#8216;upland&amp;#8217; environments. Our sampling approach demonstrates that detecting change in soil carbon empirically, with confidence, is unlikely to be possible in these diverse landscapes, with implications for predicting carbon sequestration potential as climate mitigation.

Land use change can have a strong impact on soil carbon dynamics and carbon stocks in urban areas. Due to rapid urbanization, large areas of land have been paved, and other areas have undergone rapid land use change. Evaluation of the impact of urbanization on carbon dynamics and carbon stock (30 cm) has become an issue of urgent concern. The soil carbon dynamics, due to rapid land use change in Tianjin Binhai New Area of China, have been simulated in this paper using the RothC model. Because this area is saline, a modified version of RothC that includes a salt rate modifier provided more accurate simulations than the original model. The conversion to urban green land was not accurately simulated by either of the models because of the undefined changes in soil and plant conditions. According to the model, changes of arable to grassland resulted in a decline in soil carbon stocks, and changes of grassland to forest and grassland to arable resulted in increased soil carbon stocks in this area. Across the whole area simulated, the total carbon stocks in 2010 had decreased due to land use change by 6.5% from the 1979 value. By 2050, a further decrease of 21.9% is expected according to the 2050 plan for land use and the continuing losses from the soils due to previous land use changes.

BackgroundLand use change plays a vital role in global carbon dynamics. Understanding land use change impact on soil carbon stock is crucial for implementing land use management to increase carbon stock and reducing carbon emission. Therefore, the objective of our study was to determine land use change and to assess its effect on soil carbon stock in semi-arid part of Rajasthan, India. Landsat temporal satellite data of Pushkar valley region of Rajasthan acquired on 1993, 2003, and 2014 were analyzed to assess land use change. Internal trading of land use was depicted through matrices. Soil organic carbon (SOC) stock was calculated for soil to a depth of 30 cm in each land use type in 2014 using field data collection. The SOC stock for previous years was estimated using stock change factor. The effect of land use change on SOC stock was determined by calculating change in SOC stock (t/ha) by deducting the base-year SOC stock from the final year stock of a particular land use conversion.ResultsThe total area under agricultural lands was increased by 32.14% while that under forest was decreased by 23.14% during the time period of 1993–2014. Overall land use change shows that in both the periods (1993–2003 and 2003–2014), 7% of forest area was converted to agricultural land and about 15% changes occurred among agricultural land. In 1993–2003, changes among agricultural land led to maximum loss of soil carbon, i.e., 4.88 Mt C and during 2003–2014, conversion of forest to agricultural land led to loss in 3.16 Mt C.ConclusionThere was a continuous decrease in forest area and increase in cultivated area in each time period. Land use change led to alteration in carbon equity in soil due to change or loss in vegetation. Overall, we can conclude that the internal trading of land use area during the 10-year period (1993–2003) led to net loss of SOC stock by 8.29 Mt C. Similarly, land use change during 11-year period (2003–2014) caused net loss of SOC by 2.76 Mt C. Efforts should be made to implement proper land use management practices to enhance the SOC content.

Global climate change is closely tied to CO2 emissions, and implementing conservation-agricultural systems can help mitigate emissions in the Amazon. By maintaining forest cover and integrating sustainable agricultural practices in pasture, these systems help mitigate climate change and preserve the carbon stocks in Amazon forest soils. In addition, these systems improve soil health, microclimate regulation, and promote sustainable agricultural practices in the Amazon region. This study aimed to evaluate the CO2 emission dynamics and its relationship with soil attributes under different uses in the Amazon. The experiment consisted of four treatments (Degraded Pasture—DP; Managed Pasture—MP; Native Forest—NF; and Livestock Forest Integration—LF), with 25 replications. Soil CO2 emission (FCO2), soil temperature, and soil moisture were evaluated over a period of 114 days, and the chemical, physical, and biological attributes of the soil were measured at the end of this period. The mean FCO2 reached values of 4.44, 3.88, 3.80, and 3.14 µmol m−2 s−1 in DP, MP, NF, and LF, respectively. In addition to the direct relationship between soil CO2 emissions and soil temperature for all land uses, soil bulk density indirectly influenced emissions in NF. The amount of humic acid induced the highest emission in DP. Soil organic carbon and carbon stock were higher in MP and LF. These values demonstrate that FCO2 was influenced by the Amazon land uses and highlight LF as a low CO2 emission system with a higher potential for carbon stock in the soil.

Improving the accuracy of estimating greenhouse gas absorption remains an urgent problem. Identification of the ratio of carbon stocks in soils and stand biomass of young and mid-aged forests will allow clarifying the direction of carbon fluxes in forest ecosystems during the development period most productive for atmospheric decarbonization. Increasing the accuracy of carbon stocks in components of forest ecosystems is necessary to recognize the real absorption capacity of Russian forests at the international level. The purpose of this study was to determine the carbon stocks in stand biomass and soils of young and mid-aged forests in the Republic of Tatarstan, as well as their ratio for forests of different species composition and origin. The studies were conducted on 6 sample plots in the most common forest stands aged 10 to 40 years. Organic carbon stocks in soils, stand biomass and other components of forest ecosystems located on sod-podzolic soils were determined. Total carbon stocks, the share of individual components and the ratio of stocks in stand biomass and soils were calculated. It was found that carbon stocks in the biomass of young stands of natural origin ranged from 8.5 to 50.8 t/ha, while in artificial stands they were 123.0 t/ha, and in mid-aged forests – 102.6–173.4 t/ha. Maximum carbon stocks were found in the biomass of stands of mid-aged birch forest, minimum — in young birch forest. Total organic carbon stocks in the studied ecosystems can vary by up to five times and range from 41.4 t/ha to 208.4 t/ha. The share of stand biomass in the structure of total ecosystem stocks ranged from 20.4 % to 91.4 %. Carbon stocks in sod-podzolic soils of the sample sites varied from 5.5 t/ha to 38.9 t/ha. This was lower than the reference values, but even in this case, soil carbon stocks account for 4.1 % to 73.7 % of the total ecosystem carbon stocks. Clarification of carbon stocks in soils of forested areas should be continued. Perhaps, regional databases on soil carbon stocks should be created, taking into account not only the species and age composition of the forest, but also the taxonomic affiliation of soils. In a 10-year-old birch forest the ratio of carbon stocks in the stand and soil was 3:10, in a 25-year-old birch forest it changed to 11:2, in a young pine forest of natural origin it was about 2:1, in artificial pine plantations of the same age it was 22:1. In natural birch forests, during the transition from young forests of age class I to mid-aged forests, carbon stocks in stand biomass increased by 20.5 times. The results obtained demonstrate the active participation of young and mid-aged natural forests in atmospheric decarbonization, with the main carbon sink at this stage of forest ecosystem development occurring in phytomass. Carbon stocks in soil are more conservative. The ratio of carbon stocks in stand biomass and soils of young aspen and middle-aged oak forests was close to the values for natural forests of other species of the same age. Carbon stocks in stand biomass of artificial pine planting was 2.5 times higher than in natural pine forest of the same age (25 years). Further research is required to draw scientifically grounded conclusions on the contribution of natural and planted forests to carbon sequestration.

Impact of deforestation on soil carbon stock and its spatial distribution in the Western Black Sea Region of Turkey

Abstract. An estimate of organic carbon stored in French soils to a depth of 30 cm was made using data from geo‐referenced databases. We produced statistics on carbon stocks in soils according to land use, different land uses and soil type. Then, using a combination of maps of soil and land use we were able to estimate regional and national carbon stocks. This soil carbon map of France allowed us to identify the main controlling factors of the carbon distribution: land use, soil type in some cases, clay content, and elevation. Carbon stocks in French soils were found to be about 3.1 Pg (10 15 g).

Forest conversions may lead to an accumulation of carbon in vegetation, but little is known about changes in soil C storage with establishment of plantation forests. Understanding these effects is important to addressing issues relevant to ecosystem function and productivity, and to global balance of carbon. The study investigated the effects of the created coniferous plantations on former beech and pasture sites on the soil organic carbon storage. The major forest-related land-uses in the high mountainous regions of central Stara Planina Mountain were investigated: mountainous pasture, coniferous plantations (planted on previous pasture and beech forests between four and five decades ago) and natural beech forests. The experimental data of soil properties, conducted in 2005, 2006 and 2007, were used in determining the variations in organic carbon storage in forest litter and in mineral soil under different land-use patterns. At each site five representative soil profiles were opened and described giving a total 75 soil samples from the soil layers respectively at 0-10, 10-30 and 30-50 cm depth. A total of 55 samples from forest floor layers (Aol, Aof, Aoh and greensward) were collected with 25:25 cm plastic frame. The main soil properties were determined in accordance with the standardized methods in the Laboratory of soil science at the Forest Research Institute - BAS. The IPCC Good Practice Guidance for Land Use, Land Use Change and Forestry was used to estimate the soil organic carbon stock in soil and litter. The results obtained showed that the SOC stock was quite similar among forest land-uses. The conversion of natural beech forests to coniferous plantations in studied region is related with slightly expressed decrease in soil carbon storage. The values of SOC stocks in 0-50 cm soil layer in these sites were 8.5 (?2.1) tones/ha for pine and 11.0 (?1.4) tones/ha for spruce, while under the natural beech forest it was 14.8 (?1.0) tones/ha. The SOC stock in mountainous pasture was 20.7 (? 6.5) tones/ha, while in spruce plantation created on previous pasture it was 13.5 (?2.7) tones/ha. Our finding showed that forest conversions effect in central Stara Planina Mountain is expressed by decrease in SOC stock related with losses of carbon from the upper mineral soil decades after creation of coniferous plantations. Nevertheless the relatively large organic carbon storage in forest litter in the spruce plantations compensated C lost from mineral soil after the land-use change. The overall carbon stock both in forest litter and soil under plantations ranged from 56 tones/ha (pine) to 77 tones/ha (spruce), while under natural beech forest and pasture the values were 70 and 81 tones/ha respectively. But in terms of stability C sequestrated in mineral soil is more desirable than C sequestrated in forest floor which are more vulnerable to decomposition following disturbances. The application of silvicultural activities in coniferous plantations created by conversion of forest lands or grasslands in the region of central Balkan is desirable to improve the carbon sequestration in soils.