Enhancement Of Soil Organic Carbon Research Articles

Carbon Farming and the Commission Proposal for a Regulation on a Certification Framework for Carbon Removals: a Legal Perspective

Abstract Carbon farming is a term associated with land-based practices, agricultural practices that aim at reducing emissions and sequestering carbon. These are, for example, agroforestry practices and practices that result in the maintenance and enhancement of soil organic carbon through the exploitation of the carbon cycle and the sequestration potential of soils. Given the evident links with climate change mitigation, the subject matter of carbon and carbon removals has seen important developments in the European Union (EU) in the past few years. This has culminated in the adoption of a Commission Communication on sustainable carbon cycles and a Commission Proposal for a Regulation on a certification framework for carbon removals. This contribution is meant to address the content and the potentially problematic aspects of the Commission Proposal from a legal perspective.

Enhancement of Soil Organic Carbon, Water Use Efficiency and Maize Yield (Zea mays L.) in Sandy Soil through Organic Amendment (Grass Peat) Incorporation

The efficient use of organic amendment (OM) is considered an economic, environmental and sustainable practice to improve soil quality, especially the accumulation of organic carbon (C) and water use efficiency (WUE) in dryland agriculture. However, the effect of different OM on soil nutrients, organic carbon fractions, water content and maize yield is unclear in arid and semi-arid regions with sandy soil. Field experiments with four OM, grass peat (GP), biochar (BC), organic fertilizer (OF) and maize straw (MS), were conducted with an equivalent amount of C input on the southeastern edge of Mu Us Sandy Land in China. Results indicated that the soil nutrients and labile organic carbon (DOC, MBC, KMnO4-C and POC) concentrations were higher under OM (GP, BC, OF and MS) treatments than in CK in the 0–0.10 m soil layers. GP treatment remarkably improved carbon pool index values (1.63, 2.51 and 2.24, respectively) in all layers compared to CK (1.00). At maturity stages of maize, the soil water content (SWC) under GP and OF treatments (11.3–13.4%) was remarkably higher than that in CK treatment (around 10.0%). Yield and WUE were remarkably greater in GP and OF treatments compared to CK. The results proved that GP amendment is superior for barren sandy soil than BC, OF and MS treatments in improving soil nutrients, organic carbon sequestration, WUE and crop yield in China.

Effects of land use/cover changes on soil organic carbon stocks in Qinghai-Tibet plateau: A comparative analysis of different ecological functional areas based on machine learning methods and soil carbon pool data

Understanding the process of land use/cover changes (LUCC) can provide experience on the enhancement of soil organic carbon (SOC) stocks and carbon sequestration potential for different areas. This study is uniquely to divide different ecological functional areas, and originally combine the machine learning method and soil carbon pool dataset for regional comparative analysis, to compare and quantitatively analyze the drivers of LUCC and the changes in SOC stocks effected by LUCC over 30 years. The results show that topography and climate changes are the main drivers affecting LUCC in four natural areas, while soil factors and population changes do not cause significant effects. The total SOC stocks in Qinghai was increased by 71.18 Tg C and 107.19 Tg C in 0–30 cm and 0–300 cm layers, respectively, and the highest SOC stocks within 0–300 cm were in Pastoral area. Desert and Gobi area had the lowest SOC stocks in both 0–30 cm and 0–300 cm layers. SOC stocks increased in both 0–30 cm and 0–300 cm layers only in Sanjiangyuan Natural Reserve, while the Desert and Gobi area showed a decrease in both over 30 years. This study emphasizes the significant impact of grassland changes on SOC stocks, indicating the importance of considering these changes in land management and ecological protection policies. The initial and original SOC stocks of pre-LUCC may influence the SOC stocks in post-LUCC. The response of SOC stocks changes to LUCC was varies in different areas. The heterogeneity of different ecological functional areas is affected by multiple factors and SOC stocks will become more complex among these areas in the future. These findings contribute to the development of ecological protection policies and the enhancement of regional land management strategies.

Soil organic carbon and nitrogen sequestration following grazing exclusion on the Loess Plateau, China

Enhancement of soil organic carbon (SOC) and nitrogen (N) storage in degraded ecosystems is of great significance for improving soil quality and mitigating climate change. Grazing exclusion is an effective management practice to restore degraded ecosystems in drylands. However, the spatio-temporal dynamics and regulating factors of SOC and N sequestration in degraded ecosystems following grazing exclusion has not been clearly explored. Using synthesized data from 38 peer-reviewed publications, we investigated the rates of SOC (RSOC) and soil total N (RN) stock changes and their controlling factors following grazing exclusion in the Loess Plateau of China. Grazing exclusion significantly increased SOC and total N stock in most sites. The average RSOC was 0.57, 0.64 and 0.7 Mg ha–1yr−1 and the average RN was 0.033, 0.031 and 0.036 Mg ha–1yr−1 at 0–20, 20–40 and 40–60 cm soil depths, respectively. RSOC showed a Poisson function relation with the duration of grazing exclusion. RSOC and RN did not significantly change with mean annual precipitation, but they were negatively correlated with mean annual temperature at 0–20 cm. RSOC at each soil depth was positively correlated with altitude. The strong coupling relationship between RSOC and RN resulted in no significant change in the ratio of SOC to total N between grazing exclusion and grazing sites over time. The results show that altitude, age of GE and initial SOC and N contents rather than precipitation controls these processes in the Loess Plateau. Grazing exclusion promotes SOC and N sequestrations more than 30 years in the degraded lands of the Loess Plateau. The inherent increase of soil N would be beneficial to soil carbon sequestration during the recovery process.

Influence of land use types on soil carbon fractions in the Qaidam Basin of the Qinghai-Tibet Plateau

Soil carbon is an essential component that influences soil health and agronomic productivity, and land-use practices significantly impact soil carbon stocks. In this study, the researchers investigated the impact of various land-use types (farmland, orchards, grasslands, and facility lands) on soil organic carbon (SOC) fractions in the Qaidam Basin of China's Qinghai-Tibet Plateau. The soil samples were taken from the 0–10 and 10–20 cm depths. The particulate organic carbon (POC) and mineral-associated organic carbon (MAOC) fractions of various land uses have been measured. The results revealed that grasslands had the greatest POC/SOC ratio (0.59), with POC accounting for the majority of the SOC fraction. In contrast, all other land-use types (facility land, orchards, and farmland) had greater MAOC/SOC ratios than POC/SOC. The facility land had the highest SOC content (17.75 g kg−1), and orchard had the lowest (8.51 g kg−1). The grassland had the highest POC content (9.82 g kg−1) at a depth of 0–10 cm. The trend for MAOC content among the various land-use types was facility lands > farmlands > grasslands > orchards. The soil pH was also observed to be moderately alkaline, with an average of 8. The orchard has the highest bulk density (BD), measuring 1.38 g cm−3. The grasslands contained the highest amount of total nitrogen (TN) (2.2 g kg−1) while the agricultural fields contained the highest amount of total phosphorus (TP) (1.16 g kg−1). In addition, facility lands showed the highest level of microbial activity compared to other land-use types. According to the findings, SOC, POC, and MAOC fractions had considerably positive associations with TN and microbial biomass carbon (MBC), but were significantly negatively associated with metabolic CO2. The findings imply that different land-use types can have a considerable impact on the quality and amount of soil organic carbon, which has consequences for soil health and ecosystem processes. The findings also highlight the significance of long-term land management practices that promote the preservation and enhancement of soil organic carbon in various land-use systems.

Changes in soil organic carbon and nitrogen pool sizes, dynamics, and biochemical stability during ∼160 years natural vegetation restoration on the Loess Plateau, China

Natural vegetation restoration has been reported as an effective strategy for the enhancement of soil organic carbon (SOC) and nitrogen (SON) sequestration in degraded ecosystems. However, changes in SOC and SON pool sizes, dynamics, and biochemical stability to natural vegetation restoration remain inadequately addressed. For this study, we investigated carbon (C) and nitrogen (N) contents and δ13C and δ15N values of SOC and SON pools, their labile C and N (LSOC and LSON, respectively), and recalcitrant C and N (RSOC and RSON, respectively) along 0–60 cm soil depths spanning ∼160 years of natural vegetation restoration on the Loess Plateau, China. Our results revealed that natural vegetation restoration greatly enhanced SOC, SON, LSOC, LSON, RSOC, total N, water-soluble organic C, and mineralizable organic C in the topsoil (0–20 cm), while it had little influence on the deeper soil layers (20–60 cm). The concentrations and stocks of SOC and SON in the topsoil increased significantly during the later restoration stages. The recalcitrant index for C at the 0–40 cm soil depths was highest in climax Quercus liaotungensis forest, while the recalcitrant index for N was unchanged at 0–20 and 40–60 cm soil depths between vegetation restoration stages. The δ13C values of SOC, LSOC, and RSOC, and δ15N values of SON and LSON were more enriched in the deeper soil layers relative to the topsoil, for the majority of restoration stages. The δ15N values of SON, LSON, and RSON in the topsoil were more enriched during the early restoration stages compared to the later restoration stages. Our results suggested that long-term natural vegetation restoration enhanced SOC and SON sequestration, increased biochemical stability of SOC, altered the dynamics of SOC and SON in the topsoil of degraded ecosystems through the increased inputs of plant residuals, and reduced the decomposition soil organic matter.

Soil organic carbon enhancement in diverse temperate riparian buffer systems in comparison with adjacent agricultural soils

Soil organic carbon enhancement in diverse temperate riparian buffer systems in comparison with adjacent agricultural soils

Vertical Root Distribution of Different Cover Crops Determined with the Profile Wall Method

Many benefits of cover crops such as prevention of nitrate leaching, erosion reduction, soil organic carbon enhancement and improvement of soil structure are associated with roots. However, including root characteristics as a criterion for cover crop selection requires more knowledge on their root growth dynamics. Seven cover crop species (crimson clover, winter rye, bristle oats, blue lupin, oil radish, winter turnip rape and phacelia) were grown in a two-year organically managed field experiment in Germany to screen them for root intensity and vertical root distribution. Root length density (RLD) and proportion of root length in large-sized biopores were determined before and after winter with the profile wall method. RLD and cumulative root length were analysed using a three-parameter logistic function, and a logistic dose-response function, respectively. Fibrous rooted winter rye and crimson clover showed high RLD in topsoil and had a shallow cumulative root distribution. Their RLD increased further during winter in topsoil and subsoil. The crops with the highest RLD in the subsoil were taprooted oil radish, winter turnip rape and phacelia. Bristle oat had intermediate features. Blue lupin had low RLD in topsoil and subsoil. Phacelia, oil radish, winter turnip rape and bristle oat showed the highest share of root length in biopores. These complementary root characteristics suggest that combining cover crops of different root types in intercropping may be used to enhance overall RLD for maximizing cover crop benefits.

The relevance of sustainable soil management within the European Green Deal

The new European Green Deal has the ambition to make the European Union the first climate-neutral continent by 2050. The European Commission presented an ambitious package of measures within the Biodiversity Strategy 2030, the Farm to Fork and the European Climate Law including actions to protect our soils. The Farm to Fork strategy addresses soil pollution with 50 % reduction in use of chemical pesticides by 2030 and aims 20 % reduction in fertilizer use plus a decrease of nutrient losses by at least 50%. The Biodiversity Strategy has the ambition to set a minimum of 30 % of the EU’s land area as protected areas, limit urban sprawl, reduce the pesticides risk, bring back at least 10 % of agricultural area under high-diversity landscape features, put forward the 25 % of the EU’s agricultural land as organically farmed, progress in the remediation of contaminated sites, reduce land degradation and plant more than three billion new trees. The maintenance of wetlands and the enhancement of soil organic carbon are also addressed in the European Climate Law. The new EU Soil Observatory will be collecting policy relevant data and developing indicators for the regular assessment and progress towards the ambitious targets of the Green Deal.

Earthworm: A Natural Ecofriendly Organism for Recycling of Organic Residues and Improvement of Soil Health by Vermicompost

Vermicompost of agriculture waste is an important method in which organic waste such as leaves or stalks of agricultural field is converted into useful compost by means of worms is useful to the environment. Earthworm and microbes acts together and breaks down the complex organic matter of agricultural field and resulting material is rich in nutrients and oxygen. Composting is becoming an effective way to increase organic matter of soil. In addition to increasing organic matter of soil compost also increases soil microbial population (Pera et al., 1983; Perucci, 1990), which leads to the improvement of soil quality. The entire residues after crop is harvested must go back to the soil to replenish the lost nutrient, so vermicompost is considered as excellent way to recycling nutrient in the ecosystem. Soil organic carbon enhancement through crop residues recycling by means of vermicomposting along with fertilizers and integrated nutrient management (INM) are major option to improves soil health and crop productivity. The major objective to vermicomposting is that more ground water recharge and lesser depletion of water table as well as reduces soil salinity and less pollution by agrochemicals.DOI: http://dx.doi.org/10.3126/ijasbt.v1i4.9130 Int J Appl Sci Biotechnol, Vol. 1(4): 171-175

The effect of chemical fertilizer application on carbon input and export in soil—A pot experiment with wheat using natural 13C abundance method

The enhancement of soil organic carbon (SOC) is important for sustainable agriculture, while changes in SOC depend on the balance between carbon (C) input and export. To investigate how chemical fertilizers contribute to C input (e.g. plant-derived C) and export (e.g. original SOC decomposition) in soil, a wheat (a C3 plant) pot experiment was conducted using a Phaeozem that had previously been used to cultivate maize (a C4 plant). The natural 13C abundance method was used to quantify wheat-derived SOC (WSC) and microbial respiration using the original SOC (Rmicrobial) during the wheat growing season. The wheat grain, WSC, wheat-derived C (WDC: including WSC, root and stubble biomass C) and Rmicrobial-derived CO2 emission (SCE) in fertilized treatments increased by 4.8–31.1%, 48.9–122.4%, 21.3–62.2% and 6.0–51.8%, respectively, when compared to unfertilized treatments. The total SOC in the post-experimental soil increased by 0.14–0.97% when compared to pre-experimental soil because the WSC input was larger than the SCE export, and it would be increased further if wheat root and stubble biomass C were included. Therefore, application of chemical fertilizer not only directly increases crop yield, but also indirectly contributes to C sequestration by favoring crop growth and crop-derived C input in soil.

Storage and forms of organic carbon in a no-tillage under cover crops system on clayey Oxisol in dryland rice production (Cerrados, Brazil)

The management and enhancement of soil organic carbon (SOC) is very important for agriculture (fertility) as well as for the environment (carbon (C) sequestration). Consequently, changes in soil management may alter SOC content. No-tillage (NT) practices are potential ways to increase SOC. We studied the SOC from agricultural soils in the Cerrados in Central Brazil. We compared two different tillage systems: conservation agriculture with no-tillage under cover crops (NT) and disc tillage (DT) for 5 years in a context of rainfed rice production. The soil is a dark red Oxisol with high clay content (about 40%). The objectives of the study were: (i) to evaluate the short-term (5 years) impact of tillage systems on SOC stocks in an Oxisol and (ii) to better understand the dynamics of SOC in different fractions of this soil. We first studied the initial situation in 1998, and compared it to the 2003 situation. NT with cover crop ( Crotalaria) was found to increase the storage of C in the topsoil layer (0–10 cm) compared to DT. The difference observed for the 0–10 cm layer under NT in comparison with DT represented C enrichment under no-tillage amounting to 0.35 Mg C ha −1 year −1 and corresponding to less than 10% of cover crops residues returned to the soil. A particle-size fractionation of soil organic matter (SOM) showed that differences in total SOC between NT and DT mainly affected the 0–2 μm fraction and, to a smaller extent the 2–20 μm fraction. This specific enrichment of SOC in the silt and clay fraction was attributed to (i) the storage of a water soluble C in the field and (ii) the effect of soil biota and especially fauna activity. The mean residence time of carbon associated with the fine fractions being rather long, it might be assumed that the preferential storage in fine fractions resulted in a long-term carbon storage. This study suggests a positive short-term effect of a no-tillage system on C sequestration in an Oxisol.

Carbon budget and seasonal carbon dioxide emission from a central Ohio Luvisol as influenced by wheat residue amendment

Enhancement of soil organic carbon (SOC) stocks through mulching has been proposed, and although this practice can alter several soil properties, its impact on the temporal variability of carbon dioxide (CO 2) emission from soils has not been widely investigated. To that end, we monitored CO 2 fluxes from a central Ohio Luvisol (fine, mixed, mesic Aeric Ochraqualf) amended with wheat ( Triticum aestivum L.) straw applied at rates of 0 (M0), 8 (M8) and 16 (M16) Mg dry matter ha −1 per year and supplemented with fertilizer (244 kg N ha −1 per year) or without. The experimental design was a randomized complete block design with three replications. The intensity of CO 2 emission was higher in the late winter (mean: 2.79 g CO 2-C m −2 per day) and summer seasons (2.45 g CO 2-C m −2 per day) and lowest in the autumn (1.34 g CO 2-C m −2 per day). While no significant effect of N fertilization on CO 2 emission was detected, soil mulching had a significant effect on the seasonal variation of CO 2 fluxes. The percentage of annual CO 2 emitted during the winter and spring was similar across treatments (17–22%); however, 43% of the annual CO 2 loss in the M0 plots occurred during the summer as opposed to 26% in the mulch treatments. A close relationship ( F=0.47 X+4.45, R 2=0.97, P<0.001) was found between annual CO 2 flux ( F, Mg CO 2-C ha −1) and residue-C input ( X, Mg C ha −1). Litter and undecomposed residue amounted to 0.32 and 0.67 Mg C ha −1 per year in the M8 and M16 plots, respectively. After 4 years of straw application, SOC stocks (0–10 cm) were 19.6, 25.6 and 26.5 Mg C ha −1 in the M0, M8 and M16 treatments, respectively. The results show that soil mulching has beneficial effect on SOC sequestration and strongly influence the temporal pattern of CO 2 emission from soils.

Potential of mine land reclamation for soil organic carbon sequestration in Ohio

Soils are an effective sink for carbon storage and immobilization through biomass productivity and enhancement of soil organic carbon (SOC) pool. The SOC sink capacity depends on land use and management. Degraded lands lose large amounts of C through SOC decomposition, erosion, and leaching. Thus, restoration of disturbed and degraded mine lands can lead to increase in biomass productivity, improved soil quality and SOC enhancement and sequestration. Reclamation of mined lands is an aggrading process and offers significant potential to sequester C. A chronosequence study consisting of 0-, 5-, 10-, 15-, 20- and 25-year-old reclaimed mine soils in Ohio was initiated to assess the rate of C sequestration by pasture and forest establishment. Undisturbed pasture and forest were used as controls. The SOC pool of reclaimed pasture sites increased from 15·3 Mg ha−1 to 44·4 Mg ha−1 for 0–15 cm depth and from 10·8 Mg ha−1 to 18·3 Mg ha−1 for 15–30 cm depth over the period of 25 years. The SOC pool of reclaimed forest sites increased from 12·7 Mg ha−1 to 45·3 Mg ha−1 for 0–15 cm depth and from 9·1 Mg ha−1 to 13·6 Mg ha−1 for 15–30 cm depth over the same time period. The SOC pool of the pasture site stabilized earlier than that of the forest site which had not yet attained equilibrium. The SOC sequestered in 0–30 cm depth over 25 years was 36·7 Mg ha−1 for pasture and 37·1 Mg ha−1 for forest. Copyright © 2000 John Wiley & Sons, Ltd.