C sequestration Research Papers - Academia.edu (original) (raw)

2025, Journal of Agricultural and Food Chemistry

Humic matter in virgin and cultivated Vertisols and Arenosols from Pandamatenga (northern Botswana) has been studied by chemical fractionation and visible and infrared derivative spectroscopies. The in vitro soil respiration was also determined. Soils contained <15 g of total C kg -1 and displayed scant mineralization activity. In Vertisols, cultivation has led to scarce significant changes in humus characteristics, pointing to a noteworthy resilience of the organic matter. Humic acids showed a very dark color, indicating a large concentration of aromatic structures and stable free radicals. Infrared spectra were featureless and alike. This strong structural stability is also suggested by Curie-point pyrolysis of humic acids, which failed to yield substantial amounts of diagnostic products, mainly in the case of Vertisols. Some unexpected similarities between Vertisols and Arenosols indicate that the influence of external factors on the humic acid formation processes prevails on that of the geological substrate. In Pandamatenga soils only small amounts of recalcitrant C and N forms are sequestered; they represent stable pools relatively independent from short-or medium-term climatic changes or management practices.

2025

In Finland, peat harvesting sites are utilized down almost to the mineral soil. In this situation the properties of mineral subsoil are likely to have considerable influence on the suitability for the various after-use forms. The first aim of this study was to recognize the chemical and physical properties of mineral subsoils, which may limit after-use alternatives of cut-over peatlands. The second aim was to define a minimum practice for mineral subsoil studies, to enable safe after-use planning. Also the role of different geological areas was studied: chemical characteristics of the mineral subsoils were assumed to be related to the geological areas. The future percentages of the different after-use forms were predicted to help planning both economical and environmental management of the after-use. Predicting the future landuse split between different after-use forms made it possible to predict also carbon accumulation in this future situation. Carbon accumulation effectiveness before the intervention was evaluated on three sites (representing sites typically considered for peat production). Mineral subsoils of 54 different peat production areas (9800 hectares) were studied. In field conditions all mineral subsoils were classified to either tills or various sorted sediments. Laboratory studies included sieving and areometer analysis. Other general items studied were pH, electrical conductivity, organic matter, water soluble nutrients (P, NO 3 -N, NH 4 -N, S and Fe) and exchangeable nutrients (Ca, Mg and K). In some cases also other elements were analysed. In additional case studies 3 mires (927 hectares) in Oulu district were studied. These sites represented peatlands typically considered for peat production. Their carbon accumulation history was studied. Items analysed were bulk density, dry weight and ash content. Also a few pollen profiles were determined in laboratory. 14 C dating was carried out on 5 sampling points. Some after-use limiting properties in mineral subsoils were detected. Areas with relatively sulphur rich mineral subsoil and pool-forming areas with very fine and compact mineral subsoil together covered approximately 1/5 of all areas. These areas were unsuitable for commercial use. They were recommended for example for mire regeneration. Another approximate 1/5 of the areas included very coarse or very fine sediments. Commercial use of these areas would demand special techniques -like using the remaining peat layer for compensating properties missing from the mineral subsoil. In some till areas also presence of large boulders limited agricultural use. One after-use form was seldom suitable for one whole released peat production area. Three typical distribution patterns (models) of different mineral subsoils within individual peatlands were found. 57 % of studied cut-over peatlands were well suited for forestry. In a conservative calculation 26% of the areas were clearly suitable for agriculture, horticulture or energy crop production. If tills without large boulders were included, the percentage of areas suitable to field crop production would be 42 %. 9-14 % of all areas were well suitable for mire regeneration or bird sanctuaries, but all areas were considered possible for mire regeneration with correct techniques. Also another 11 % was recommended for mire regeneration to avoid disturbing the mineral subsoil, so total 20-25 % of the areas would be used for different forms of rewetting

2025, Agriculture, Ecosystems & Environment

Agriculture in the Mediterranean basin is currently contributing to greenhouse gas emissions (GHG) and in the future is expected to be strongly affected by climate change. Increasing soil organic carbon (SOC) via soil organic matter (SOM) improvement is widely regarded as a way to both mitigate and adapt to climate change. Using as a case study the Mediterranean coastal area in Spain, which is regarded as one of the most intensively managed areas in Europe for orchards and horticultural cropping, we analyzed the potential for climate change mitigation of introducing different practices that are expected to increase SOC. We selected both as a single Agriculture, Ecosystems & Environment 238 (1): 153-167 (2017) 2 measure and in combination, cover cropping and application to the soil of the available underutilized exogenous organic matter (EOM), treated (e.g. composted or digested) or nontreated. These practices were compared against a baseline scenario that intended to reflect the current practices in the area (e.g. all livestock manure produced in the area is applied to the agricultural soil). We carried out a modelling exercise at the regional scale using the agricultural activity data and current climatic conditions as inputs. Modelling runs were performed coupling a widely used dynamic model of SOC turnover (RothC) with a model to simulate the GHG emissions from EOM processing or storage prior to soil application (SIMSWASTE). Results indicate that the most promising practice, considered as a single measure and with respect to the baseline, was introducing cover crops in woody cropping systems. This practice resulted in an increase of 0.44 Mg C ha -1 yr -1 during the first 20 years (range 0.41-0.52 Mg C ha - 1 yr -1 ) and led to a total SOC accumulation of about 30 Tg C after 100 years. Amendment of all agricultural land with available underutilized EOM resulted in an increase of up to 0.09 Mg C ha -1 yr -1 (range 0.07-0.16 Mg C ha -1 yr -1 ) as a single measure (urban waste) and 0.13 Mg C ha -1 yr -1 (range 0.11-0.21 Mg C ha -1 yr -1 ) as a combined measure (urban waste and composted agroindustry by-products), leading to a total SOC accumulation of about 7 Tg C (urban waste) and 10 Tg C (urban waste and composted agroindustry by-products) after 100 years. Manure anaerobic digestion or composting as a single measure did not result in significant SOC changes but, if GHG emissions and savings from manure storage and processing management stages are considered, they could help to reduce about 4.3 (anaerobic digestion) or 1.1 Tg CO2eq yr -1 (composting) in the study area, which represents a significant amount compared with total agricultural emissions in Spain.

2025, Biogeosciences discussions

Quantifying soil organic carbon stocks (SOC) and their dynamics accurately is crucial for better predictions of climate change feedbacks within the atmosphere-vegetationsoil system. However, the components, environmental responses and controls of the soil CO 2 efflux (R s ) are still unclear and limited by field data availability. The objectives of this study were (1) to quantify the contribution of the various R s components, specifically its mycorrhizal component, (2) to determine their temporal variability, and (3) to establish their environmental responses and dependence on gross primary productivity (GPP). In a temperate deciduous oak forest in south east England hourly soil and ecosystem CO 2 fluxes over four years were measured using automated soil chambers and eddy covariance techniques. Mesh-bag and steel collar soil chamber treatments prevented root or both root and mycorrhizal hyphal in-growth, respectively, to allow separation of heterotrophic (R h ) and autotrophic (R a ) soil CO 2 fluxes and the R a components, roots (R r ) and mycorrhizal hyphae (R m ).

2025

The aim of this study is to establish parameters to evaluate ecosystem service from carbon sequestration of the actions supported by the Sustainable Rural Development Program in watersheds of the state of Rio de Janeiro, southeastern Brazil – Rio-Rural. The RioRural program supports sustainable agriculture practices and the conservation of natural resources, such as rotational grazing systems, the protection of springs and streams, agroforestry and restoration of degraded areas. To do so, carbon stocks were determined under degraded Brachiaria spp pasture, as well as in a semideciduous broadleaf Atlantic Forest fragment. We measured carbon stock in the soil, aboveground biomass and liter components. The study area is located in the municipality of Sao Jose de Uba, northwest of the state, which has a hot and humid tropical climate and clearly defined seasons (Aw in the Kopen classification). Three 50-meter long, 1.0-meter wide transects, situated at upper, middle and footslope were d...

2025, Agronomy for Sustainable Development

Organic rules for grazing and access to outdoor area in pig production may be met in different ways, which express compromises between considerations for animal welfare, feed self-reliance and negative environmental impact such as greeehouse gas emissions and nitrate pollution. This article compares environmental impact of the main organic pig systems in Denmark. Normally sows are kept in huts on grassland and finishing pigs are being raised in stables with access to an outdoor run. One alternative practised is rearing also the fattening pigs on grassland all year round. The third method investigated was a one-unit pen system mainly consisting of a deep litter area under a climate tent and with restricted access to a grazing area. Using life cycle assessment (LCA) methodology, the emissions of greenhouse gasses of the all free range system was estimated to be 3.3 kg CO 2 -equivalents kg -1 liveweight pig, which was significantly higher than the indoor fattening system and the tent system yeilding 2.9 and 2.8 kg CO 2 -

2025, Environmental Pollution

A simple model of nitrogen (N) saturation, based on an extension of the biogeochemical model MAGIC, has been tested at two long-running heathland N manipulation experiments. The model simulates N immobilisation as a function of organic soil C/N ratio, but permits a proportion of immobilised N to be accompanied by accumulation of soil carbon (C), slowing the rate of C/N ratio change and subsequent N saturation. The model successfully reproduced observed treatment effects on soil C and N, and inorganic N leaching, for both sites. At the C-rich upland site, N addition led to relatively small reductions in soil C/N, low inorganic N leaching, and a substantial increase in organic soil C. At the C-poor lowland site, soil C/N ratio decreases and N leaching increases were much more dramatic, and soil C accumulation predicted to be smaller. The study suggests that (i) a simple model can effectively simulate observed changes in soil and leachate N; (ii) previous model predictions based on a constant soil C pool may overpredict future N leaching; (iii) N saturation may develop most rapidly in dry, organic-poor, high-decomposition systems; and (iv) N deposition may lead to significantly enhanced soil C sequestration, particularly in wet, nutrient-poor, organic-rich systems.

2025

The FORMACS project of CARE Indonesia in Kabupaten Nunukan was established to test community based forest management as an approach to enhance local livelihoods and reduce negative current trends of forest cover change. Carbon-stock monitoring is needed to evaluate the effectiveness of the project approach towards the goals and to establish a baseline of the rate of change before the project became fully effective.

2025, Ecological Applications

Conversion of abandoned cattle pastures to secondary forests and plantations in the tropics has been proposed as a means to increase rates of carbon (C) sequestration from the atmosphere and enhance local biodiversity. We used a long-term tropical reforestation project (55-61 yr) to estimate rates of above-and belowground C sequestration and to investigate the impact of planted species on overall plant community structure. Thirteen tree species (nine native and four nonnative species) were planted as part of the reforestation effort in the mid to late 1930s. In 1992, there were 75 tree species (Ͼ9.1 cm dbh) in the forest. Overall, planted species accounted for 40% of the importance value of the forest; planted nonnative species contributed only 5% of the importance value. In the reforested ecosystem, the total soil C pool (0-60 cm depth) was larger than the aboveground C pool, and there was more soil C in the forest (102 Ϯ 10 Mg/ha [mean Ϯ 1 SE]) than in an adjacent pasture of similar age (69 Ϯ 16 Mg/ha). Forest soil C (C 3 -C) increased at a rate of ϳ0.9 Mg•ha Ϫ1 •yr Ϫ1 , but residual pasture C (C 4 -C) was lost at a rate of 0.4 Mg•ha Ϫ1 •yr Ϫ1 , yielding a net gain of 33 Mg/ha as a result of 61 years of forest regrowth. Aboveground C accumulated at a rate of 1.4 Ϯ 0.05 Mg•ha Ϫ1 •yr Ϫ1 , to a total of 80 Ϯ 3 Mg/ha. A survey of 426 merchantable trees in 1959 and 1992 showed that they grew faster in the second 33 years of forest development than in the first 22 years, indicating that later stages of forest development can play an important role in C sequestration. Few indices of C cycling were correlated with plant community composition or structure. Our results indicate that significant soil C can accumulate with reforestation and that there are strong legacies of pasture use and reforestation in plant community structure and rates of plant C sequestration.

2025, Biodiversitas Journal of Biological Diversity

2025

A long-term field experiment was established in 2016 to manage subsurface soil acidity through innovative amelioration methods with the aim to increase productivity, profitability and sustainability. Deep placement of lime increased soil pH and reduced exchangeable Al% at the depth where lime was placed, but there was no evidence to show vertical alkalinity movement during the first 3 years of the experiment. Deep placement of lucerne pellets did not increase soil pH as much as expected, but reduced exchangeable Al%. Significant yield improvement was recorded from deep placement of lucerne pellets in a wet year (2016) but not in dry years experienced in 2017 and 2018, although large amount of mineral nitrogen was measured in autumn in 2017. Crop performance and soil chemical, physical and biological properties will be continually monitored to understand plant-soil interactions, the factors driving the differences in crop response to various treatments, and the long-term residual val...

2025, Pesquisa Agropecuaria Brasileira

The objective of this work was to evaluate whether balsa wood plantation and its fertilization can improve soil carbon stocks. Total carbon stocks in the soil-biomass system, at 0.0-0.30 m soil depths, were evaluated under three fertilization strategies, after three and seven years, and compared with carbon stocks from native forest and degraded pasture. At the highest fertilization level, balsa wood showed a carbon stock similar to that of the native forest (65.38 Mg ha -1 ) and, after seven years, it increased carbon stock by 18% in the soil, and by 42% in the soil-biomass system.

2025, Geoderma

No-tillage (NT) and legume cover crops generally improve the quality of tropical and subtropical soils, but the mechanisms underlying these effects are not well known. We performed a study to investigate the influence of NT and legume cover cropping on microbial cell-wall constituents [glucosamine (GlcN), taken as indicator of fungal cell-wall; muramic acid (MurN), taken as indicator of bacterial cell-wall], and on their relationships with soil aggregation and soil organic carbon (SOC) accumulation in different fractions (light fraction, and sand-, siltand clay-sized fractions) of a subtropical Acrisol in Southern Brazil. The GlcN concentration ranged from 450.5 mg kg -1 in the 0-5 cm soil layer to 20.5 in the 75-100 cm soil layer, approximately 10 times greater than MurN concentrations (53.1-2.7 mg kg -1 for the same soil layers). No-tillage and legume cover crops favoured the accumulation of fungal and bacterial cell-wall constituents in whole soil, especially in the top 5 cm, with a preferential enrichment in GlcN. Legume cover cropping and NT resulted in greater accumulation of C in the light fraction in surface soil, which favoured the fungal community that, in turn, mediated an improvement in soil aggregation. Fungal-derived glucosamine also preferentially accumulated down to 100 cm depth, and more specifically in the clay-sized fraction of soil, suggesting a specific role of fungi in SOC accumulation at depth. Overall, our study provides field-based evidence that the accrual of fungal cell-wall constituents under NT and legume cover cropping is a key process leading to aggregation and SOC accumulation in subtropical soil profiles. Recent models of SOC formation now consider microbial residues as a main source for stable soil organic matter . Moreover, SOC stabilization by mineral-organic association and soil aggregation would be favoured by labile C inputs . More field-based observations are needed to support these concepts. Cell-wall constituents of fungi and bacteria in soil can provide a "fingerprint" for SOC formation . Contents of muramic acid (MurN) and glucosamine (GlcN) have been used to distinguish bacterial and fungal cell wall residues, respectively, mainly in temperate environments (e.g. . Few studies have been performed in subtropical or tropical soils. In these studies, greater amounts of total amino-sugars,

2025

The biosphere is the thin, interconnected system of all living things and three environmental matrices of atmosphere, ocean, and soil. Organisms are coupled to each other in the traditional ecological interactions, such as the food webs. But organisms are also coupled by nutrient intakes from the matrices and waste inputs to the matrices. All together, these intakes and inputs create a global metabolism. The result is a biosphere system in which wastes from certain biochemical guilds of organisms are nutrients for other guilds, and in which free by-products from different guilds have affected the large-scale chemistry and thus habitability of the biosphere’s environmental matrices. Today, humans, through the combustion of fossil fuels and the waste emissions of the greenhouse gas carbon dioxide, are altering the chemistry of the atmosphere and the other environmental matrices, faster than the global carbon cycle can adjust. We are responsible for these changes, which will cause ever...

2025

Afforestation does not only establish new forests on treeless lands, but also changes many other aspects of the ecosystem, including the fauna, ground vegetation and soil properties. One of the most important ecosystem changes is the influence on the ecosystem carbon (C) stocks in different aboveground and belowground C pools. If afforestation is to be used as a method to sequester atmospheric carbon dioxide (CO2), to mitigate climate warming, it is important not only to consider changes in aboveground tree biomass, but also in the other four major ecosystem pools (dead wood, ground vegetation, litter layer and soil organic carbon (SOC)). Training Programe (UNU-LRT) and a public utility company (Orkuveita Reykjavikur) in Iceland. The Agricultural University of Iceland, the Icelandic Forest Service -Mógilsá, and the Forestry Association of Reykjavik provided equipment for field measurements, laboratory work and software for data management and statistical analysis. I thank all of them for their support. Bjarni Diðrik Sigurdsson has over the years advised me tirelessly and contributed immeasurably to the success of this project. From choosing the best scientific method of field measurements, laboratory protocol and most importantly, data handling and statistical analysis, Bjarni supported and guided me greatly. He was encouraging, available, highly knowledgeable, and he mentored and fully prepared me for lives beyond this project. In addition, Bjarni introduced me to networks of his science colleagues and made efforts to recommend conferences, seminars and courses that were very relevant to this project. I will never forget the constructive, consistent and well thought comments and feedbacks that Bjarni provided on this thesis. With the greatest gratitude, I wish to thank Bjarni for inspiring and developing me professionally. I would also like to thank Berglind Orradottir for her comments. Gústaf Jarl Viðarsson contributed immensely toward the stratification of my study sites into similar forest types and he made maps using GIS tool. He also helped in random selection of inventory plots which facilitated a scientifically sound estimation of the carbon sequestration by afforestation. The core contribution from Gústarf were in carrying out the field inventory of below and above-ground biomass, selection of chronosequence plots, locating the already existing plots, driving to the field and helping to translate the local language (Icelandic) to English. I am grateful for his wonderful commitment in ensuring the success of KOLOR project. Many thanks also go to Kimmo Vanhavifta for offering quick solution during field work especially fixing broken equuipment, coring soils, taking photos, operating compass and GPS finding directions. Gunnhildur Eva G. Gunnarsdóttir assisted me with a wide range of knowledge in soil sampling in the field and preparation in the laboratory. She helped me with soil sieving, ball milling, soil vii pH testing, bulk density determination, calibrating equipment and organising resources which facilitated me in meeting targets in diligent and timely manner. Baldur Vigfússon was also very resourceful in soil chemical analysis in the lab. I sincerely thank all laboratory technicians. With great honour, I would like to thank UNU-LRT management, particularly Hafdis Hanna, Berglind Orradottir and Halldóra Traustadóttir for their outstanding performance in running the programme which allowed me to successfully complete this project. They ensured that I consistently focused on the project and actively participated in extracurricular activities in my spare time which psychologically, morally and spiritually helped me to complete this project. Finally, I would like to thank my hosts (Þorhallur Asgeirsson and Sigridur Þorbjornsdottir) who have been so kind and were always available at the innermost core of my loneliness. They gave me plenty of wisdoms and advices which help me stayed connected to the local people. viii

2025, Agricultural Reviews, Volume 46 Issue 1 (February 2025)

Carbon sequestration plays a significant part in alleviating climate change by changing over climatic carbon as plant biomass and soil organic carbon. Since trees can hold greater carbon in their biomass than other plant types, perennial plantations have a vital function in mitigating the adversities in climate. Coconut is a perennial palm with a life time of around 50-60 years has the capability to store carbon for a long time, especially in the stem. Due to the increased availability of space and solar radiation reaching the understorey, the carbon sequestration capacity of coconut plantations can be considerably increased. As a result, intercropping or agroforestry in coconut lands is important not only for food and economic security but also for carbon sequestration. On an average carbon sequestration potential of coconut trees range between 37 kg tree-1 yr-1 (dwarf variety) up to 56 kg tree-1 yr-1 (tall variety). After 20 years of establishment, monoculture coconut land can be transformed into perennial mixed cropping or agroforestry system that can sequester more carbon.

2025

Less /sup 238/Pu was concentrated in the seeds than in the vegetative parts in all plant species. Leaves contained more /sup 238/Pu than the stem or pods, and the monocots had lower concentrations of /sup 238/Pu in their tissues than the dicots. Irrigation of plants affected the uptake of /sup 238/Pu, especially on the year-to-year changes in the amount of the element accumulated in the plant parts. Several more years of data must be analyzed to determine if this phenomenon is real. Soil profiles must be studied to determine what configuration changes may occur in the /sup 238/Pu in the soil. Other investigators show that soil microbes change the chemical form of plutonium in the soil and the organic complexes that are formed are more available for plant uptake.

2025

Como citar este capítulo: ALVES, Felipe Dalenogare. O Direito fundamental ao bom governo e o dever de proteção estatal: análise de algumas medidas adotadas pelo legislador na reforma da Lei de Improbidade Administrativa. In: MATOS, Marilene Carneiro; ALVES, Felipe Dalenogare; AMORIM, Rafael Amorim de (Orgs). Improbidade Administrativa: reflexões à luz da Lei n. 14.230/2021. Brasília: Edições Câmara, 2025, p. xx.

2025

Livestock systems have been identified as major emitters of greenhouse gases due to the use of extensive areas with degraded pastures. The objective of this study was to analyze carbon (CO 2 ) and methane (CH 4 ) fluxes in the atmosphere as indicators of environmental sustainability in silvopastoral systems. CO 2 and CH 4 fluxes from soil to the atmosphere were monitored in a degraded pasture (predominant species: Panicum maximum cv. Mombaça) grown in full sun and compared with areas with tree species (Bertholletia excelsa, Dipteryx odorata, and Khaya grandifoliola) and productive pasture (Panicum maximum cv. Mombaça) grown in full sun. The study area was in Mojuí dos Campos, western Pará state, Eastern Amazon, Brazil. The evaluations were conducted in a Technological Reference Unit with a silvopastoral system, where animals used the shade of trees during high-temperature periods. The fluxes were measured using an ultraportable greenhouse gas analyzer coupled with static polyvinyl chloride ring chambers installed at the soil-air interface. In conclusion, areas with integrated systems (B. excelsa + pasture and K. grandifoliola + pasture) were better mitigators of CO 2 emissions; the highest emissions occurred in the degraded pasture area during the rainiest months. The CH 4 fluxes were more intense in the areas with degraded pasture and K. grandifoliola + pasture. Converting degraded pasture areas into integrated crop-livestock-forest systems reduced greenhouse gas emissions in the Amazon over 10 years of implementation. The implementation of integrated crop-livestock-forest systems in long-deforested areas with degraded

2025, Science

Estimates of forest net primary production (NPP) demand accurate estimates of root production and turnover. We assessed root turnover with the use of an isotope tracer in two forest free-air carbon dioxide enrichment experiments. Growth at elevated carbon dioxide did not accelerate root turnover in either the pine or the hardwood forest. Turnover of fine root carbon varied from 1.2 to 9 years, depending on root diameter and dominant tree species. These long turnover times suggest that root production and turnover in forests have been overestimated and that sequestration of anthropogenic atmospheric carbon in forest soils may be lower than currently estimated.

2025

In the Australian grain belt soil constraints are often expressed as lower water use efficiency (WUE) of grain production and are compared with water limited yield, otherwise known as potential yield. The difference between constrained and potential yield is referred to as the yield gap. Among different soil constraints, sodicity is associated with the largest yield gaps across most of the wheatcropping areas of Australia, with an estimated yield loss of $A 1300 million per annum (Orton et al. 2018). Sodic soils exhibit a range of physiochemical properties including the presence of high subsoil exchangeable sodium (Na) concentrations which cause soil dispersion leading to poor subsoil structure, impeded drainage, waterlogging, denitrification and high soil strength. These properties restrict the rooting depths of crop species and subsequent water and nutrients extraction (Incerti and O'Leary 1990; Passioura and Angus 2010) leading to significant yield gaps (Adcock et al. 2007) t...

2025, Journal of Integrative Agriculture

Three long-term field trials were conducted to investigate the effects of organic amendments on the grain sustainable yield index (SYI), soil fertility index (SFI) and nutrient balance in maize–wheat cropping systems of central and southern China during 1991–2019. Five treatments were included in the trials: 1) no fertilization (control); 2) balanced mineral fertilization (NPK); 3) NPK plus manure (NPKM); 4) high dose of NPK plus manure (1.5NPKM); and 5) NPK plus crop straw (NPKS). Over time, the grain yields of wheat and maize showed an increasing trend in all four fertilization treatments at the Yangling (YL) and Zhengzhou (ZZ) locations, while they declined at Qiyang (QY). The grain yield in the NPKM and 1.5NPKM treatments gradually exceeded that of the NPK and NPKS treatments at the QY site. The largest SYI was recorded in the NPKM treatment across the three sites, suggesting that inorganic fertilizer combined with manure can effectively improve crop yield sustainability. Higher SYI values were recorded at the YL and ZZ sites than at the QY site, possibly because the soil was more acid at QY. The key factors affecting grain yield were soil available phosphorus (AP) and available potassium (AK) at the YL and ZZ sites, and pH and AP at the QY site. All fertilization treatments resulted in soil N and P surpluses at the three sites, but soil K surpluses were recorded only at the QY site. The SFI was greater in the 1.5NPKM, NPKM and NPKS treatments than in the NPK treatment by 13.3–40.0 and 16.4–63.6% at the YL and ZZ sites, respectively, and was significantly higher in the NPKM and 1.5NPKM treatments than in the NPK and NPKS treatments at the QY site. A significant, positive linear relationship was found between SFI and crop yield, and SYI and nutrient balance, indicating that grain yield and its sustainability significantly increased with increasing soil fertility. The apparent N, P and K balances positively affected SFI. This study suggests that the appropriate amount of manure mixed with mineral NPK fertilizer is beneficial to the development of sustainable agriculture, which effectively increases the crop yield and yield sustainability by improving soil fertility.

2025

The Biosphere Reserve of Yangambi (BRY) landscape is facing the challenge of conserving biodiversity while supporting the food security of local communities. Farmers, in search of fertile soil, travel long distances to establish their fields, sometimes in the core area of the reserve. Faced with this reality, agroforestry is an alternative that could contribute to improving local livelihoods while protecting forests and biodiversity in this protected area

2025, Global Biogeochemical Cycles

The carbon density and the long‐term (apparent) rate of carbon accumulation (LORCA) in the mineral subsoil of boreal mires in Finland formed by paludification were studied by comparison to adjacent forest soil sites with similar podzolic texture and topography. On the basis of 273 soil profiles from six areas, the mean carbon density in the mineral subsoil of mire sites was 1.5‐fold higher than in adjacent forest profiles. The average carbon input was 13.6 ± 1.8 (SE) g m−2 yr−1 which differed according to length of time since the onset of paludification. LORCA estimates were highest on the youngest mire sites (< 500 years) and agree with estimates obtained for peat deposits elsewhere in the boreal region. Bogs and topographically flat areas were found to have higher LORCA values than the fens and the topographically steeper areas. The carbon stored in podzols in boreal forest reach equilibrium with soil age after 1500–2000 years, while in the mineral subsoil of mires the equilibr...

2025, GCB Bioenergy

Species in the Miscanthus genus have been proposed as biofuel crops that have potential to mitigate elevated atmospheric carbon dioxide (CO 2 ) levels and nitrous oxide (N 2 O) and methane (CH 4 ) emissions. Miscanthus sinensis is widespread throughout Japan and has been used for biomass production for centuries. We assessed the carbon (C) budget and N 2 O and CH 4 emissions over the growing season for two years in a M. sinensis-dominated grassland that was naturally established around 1972 in Tomakomai, Hokkaido, Japan, which is near the northern limit for M. sinensis grassland establishment on Andisols. Average C budget was -0.31 Mg C ha -1 , which indicates C was released from the grassland ecosystem to the atmosphere. Dominant components in the C budget appeared to be aboveground net primary production of plants (1.94 to 2.80 Mg C ha -1 ) and heterotrophic respiration (2.27 to 3.11 Mg C ha -1 ). The measurement of belowground net primary production (BNPP) of plants in the M. sinensis grassland was extremely variable, thus only an approximate value could be calculated. Mean C budget calculated with the approximated BNPP value was 1.47 and -0.23 Mg C ha -1 for 2008 and 2009, respectively. Given belowground biomass (9.46 to 9.86 Mg C ha -1 ) was 3.1 to 6.5 times higher than that of aboveground biomass may provide additional evidence suggesting this grassland represents a C sink. Average CH 4 emissions across years of -1.34 kg C ha -1 would indicate this grassland acts as an atmospheric CH 4 sink. Furthermore, average N 2 O emissions across years were 0.22 kg N ha -1 . While the site may contribute N 2 O to the atmosphere, this value is lower compared with other grassland types. Global warming potential calculated with the approximated BNPP value was -5.40 and 0.95 Mg CO 2 eq ha -1 for 2008 and 2009,

2025, Verhandlungen

A key determinant o f e-flux in aquatic ecosystems is the supply o f elements relative to the demands o f producers and consumers. Uptake of e is commonly in excess relative to P or N in both autotrophs and heterotrophs, yet they may have different ways o f coping with excess e. Stoichiometric demands thus govern e-use efficiency in individual organisms, and in food webs these stoichiometric principles will affect etransfer efficiency across trophic levels. I f a high rate ofe-fixation via photosynthesis is not met by corresponding increased uptake rates ofN and P, this deficiency will yield plant biomass with low nutrient value (high e:N or e:P). Normally, plants and detritus have far higher e:N or e:P ratios than that ofthe heterotrophs (bacteria and zooplankton), which may lead to P or N-limited growth of consumers. This limitation will al so affect population dynamics o f the consumer and food web interactions. The excess e may enter the detritus pathway, it may be buried in sediments, or it may be oxidized to eoz. Thus the balance or mismatch o f elemental ratios in individual organisms and food webs will add up to a major determinant for the overall e-cycle and production:respiration ratio at the ecosystem level. This surplus of e is especially pronounced in many freshwater systems receiving high inputs of allochthonous e that will shift the balance from autotrophic to heterotrophic processes, thus reinforcing the net export of eoz from water to atrnosphere. Based on a large database o f lakes, this paper will explore an d review these stoichiometric aspects of e-metabolism and trophic transfer efficiency in lakes.

2025, Analyzing possible effects of silvopastoral systems on biodiversity and ecosystem services in temperate grasslands of southern South America. (Atena Editora)

Os sistemas silvipastorais (SPS), além do seu potencial produtivo, têm sido promovidos como estratégia de sequestro de carbono e contribuem para a conservação da biodiversidade. A revisão efectuada mostra que quando se trata da implementação destes sistemas em regiões tropicais, especialmente onde a actividade agrícola ou pecuária deslocou a vegetação natural, os efeitos são positivos em termos de sequestro de carbono, biodiversidade, dinâmica hidrológica e qualidade da água. Nas regiões subtropicais e temperadas, o SPS pode ser uma opção amiga do ambiente nas bio-regiões onde a vegetação natural é dominada por comunidades lenhosas abertas e pastagens, pela associação de gado pastoreio bem gerido. Em regiões onde a vegetação natural é pastagem, há poucas informações obtidas no SSP, para as quais foram analisadas algumas informações derivadas de sistemas florestais. As escassas evidências mostram que o sequestro de carbono poderia ser uma realidade se fossem adicionados carbono do solo e biomassa aérea, mas poderia alterar a dinâmica da água e afectar a biodiversidade da flora e da fauna.

2025

In this practice abstract the results of afforestation supported by intercropping in Hungary are summarised.

2025

Hughes for his advice, patience, encouragement and guidance throughout this study. I'm so grateful that our paths crossed and could not ask for more than that in life. My co-supervisor, Prof. Pardon Muchaonyerwa for his constructive suggestions, guidance, time and patience throughout this study. OSCA management for funding this study especially Mrs Q.G Mhlongo who did the approval in the beginning. OSCA second year students (2012 class) who helped me with sample collection. Dr P. Dlamini who helped in organising the data on excel and gave me general support, constructive suggestions and friendship. Ms Cathy Stevens from Cedara who helped with the statistical analysis. Soil Science technical staff, Mr Rajiv Singh, Mr Jothan Buthelezi, and Ms Tezi Nala. Mr Sandile Mthimkhulu and Mr Siphamandla Madikizela who helped with the aggregate stability analysis in the laboratory. Ms Ziyanda Makatini for being my source of strength throughout this study. My family, for their encouragement and support, in particular my mother, Mrs N.E Mbanjwa, who has been a source of courage throughout my academic progress and life's struggles in general.

2025, Agriculture, Ecosystems & Environment

We predicted changes in yields and direct net soil greenhouse gas (GHG) fluxes from converting conventional to alternative management practices across one of the world's most productive agricultural regions, the Central Valley of California, using the DAYCENT model. Alternative practices included conservation tillage, winter cover cropping, manure application, a 25% reduction in N fertilizer input and combinations of these. Alternative practices were evaluated for all unique combinations of crop rotation, climate, and soil types for the period 1997-2006. The crops included were alfalfa, corn, cotton, melon, safflower, sunflower, tomato, and wheat. Our predictions indicate that, adopting alternative management practices would decrease yields up to 5%. Changes in modeled SOC and net soil GHG fluxes corresponded to values reported in the literature. Average potential reductions of net soil GHG fluxes with alternative practices ranged from -0.7 to -3.3 Mg CO 2 -eq ha -1 yr -1 in the Sacramento Valley and -0.5 to -2.5 Mg CO 2 -eq ha -1 yr -1 for the San Joaquin Valley. While adopting a single alternative practice led to modest net soil GHG flux reductions (on average -1 Mg CO 2 -eq ha -1 yr -1 ), combining two or more of these practices led to greater decreases in net soil GHG fluxes of up to -3 Mg CO 2 -eq ha -1 yr -1 . At the regional scale, the combination of winter cover cropping with manure application was particularly efficient in reducing GHG emissions. However, GHG mitigation potentials were mostly non-permanent because 60-80% of the decreases in net soil GHG fluxes were attributed to increases in SOC, except for the reduced fertilizer input practice, where reductions were mainly attributed to decreased N 2 O emissions. In conclusion, there are long-term GHG mitigation potentials within agriculture, but spatial and temporal aggregation will be necessary to reduce uncertainties around GHG emission reductions and the delivery risk of the associated C credits.

2025

Changes in grassland management intended to increase productivity can lead to sequestration of substantial amounts of atmospheric C in soils. Managementintensive grazing (MiG) can increase forage production in mesic pastures, but potential impacts on soil C have not been evaluated. We sampled four pastures (to 50 cm depth) in Virginia, USA, under MiG and neighboring pastures that were extensively grazed or hayed to evaluate impacts of grazing management on total soil organic C and N pools, and soil C fractions. Total organic soil C averaged 8.4 Mg C ha -1 (22%) greater under MiG; differences were significant at three of the four sites examined while total soil N was greater for two sites. Surface (0-10 cm) particulate organic matter (POM) C increased at two sites; POM C for the entire depth increment (0-50 cm) did not differ significantly between grazing treatments at any of the sites. Mineral-associated C was related to silt plus clay content and tended to be greater under MiG. Neither soil C:N ratios, POM C, or POM C:total C ratios were accurate indicators of differences in total soil C between grazing treatments, though differences in total soil C between treatments attributable to changes in POM C (43%) were larger than expected based on POM C as a percentage of total C (24.5%). Soil C sequestration rates, estimated by calculating total organic soil C differences between treatments (assuming they arose from changing grazing management and can be achieved elsewhere) and dividing by duration of treatment, averaged 0.41 Mg C ha -1 year -1 across the four sites.

2025, Ecological Modelling

e c o l o g i c a l m o d e l l i n g 2 0 5 ( 2 0 0 7 ) 453-463 a v a i l a b l e a t w w w . s c i e n c e d i r e c t . c o m j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / e c o l m o d e l

2025, Environmental Management

Grassland management affects soil organic carbon (SOC) storage and can be used to mitigate greenhouse gas emissions. However, for a country to assess emission reductions due to grassland management, there must be an inventory method for estimating the change in SOC storage. The Intergovernmental Panel on Climate Change (IPCC) has developed a simple carbon accounting approach for this purpose, and here we derive new grassland management factors that represent the effect of changing management on carbon storage for this method. Our literature search identified 49 studies dealing with effects of management practices that ei-ther degraded or improved conditions relative to nominally managed grasslands. On average, degradation reduced SOC storage to 95% Ϯ 0.06 and 97% Ϯ 0.05 of carbon stored under nominal conditions in temperate and tropical regions, respectively. In contrast, improving grasslands with a single management activity enhanced SOC storage by 14% Ϯ 0.06 and 17% Ϯ 0.05 in temperate and tropical regions, respectively, and with an additional improvement(s), storage increased by another 11% Ϯ 0.04. We applied the newly derived factor coefficients to analyze C sequestration potential for managed grasslands in the U.S., and found that over a 20-year period changing management could sequester from 5 to 142 Tg C yr Ϫ1 or 0.1 to 0.9 Mg C ha Ϫ1 yr Ϫ1 , depending on the level of change. This analysis provides revised factor coefficients for the IPCC method that can be used to estimate impacts of management; it also provides a methodological framework for countries to derive factor coefficients specific to conditions in their region.

2025, Biogeochemistry

Current estimates of soil C storage potential are based on models or factors that assume linearity between C input levels and C stocks at steady-state, implying that SOC stocks could increase without limit as C input levels increase. However, some soils show little or no increase in steady-state SOC stock with increasing C input levels suggesting that SOC can become saturated with respect to C input. We used long-term field experiment data to assess alternative hypotheses of soil carbon storage by three simple models: a linear model (no saturation), a one-pool whole-soil C saturation model, and a two-pool mixed model with C saturation of a single C pool, but not the whole soil. The one-pool C saturation model best fit the combined data from 14 sites, four individual sites were best-fit with the linear model, and no sites were best fit by the mixed model. These results indicate that existing agricultural field experiments generally have too small a range in C input levels to show saturation behavior, and verify the accepted linear relationship between soil C and C input used to model SOM dynamics. However, all sites combined and the site with the widest range in C input levels were best fit with the C-saturation model. Nevertheless, the same site produced distinct effective stabilization capacity curves rather than an absolute C saturation level. We conclude that the saturation of soil C does occur and therefore the greatest efficiency in soil C sequestration will be in soils further from C saturation.

2025, Nutrient Cycling in Agroecosystems

Carbon sequestration in agricultural, forest, and grassland soils has been promoted as a means by which substantial amounts of CO 2 may be removed from the atmosphere, but few studies have evaluated the associated impacts on changes in soil N or net global warming potential (GWP). The purpose of this research was to (1) review the literature to examine how changes in grassland management that affect soil C also impact soil N, (2) assess the impact of different types of grassland management on changes in soil N and rates of change, and (3) evaluate changes in N 2 O fluxes from differently managed grassland ecosystems to assess net impacts on GWP. Soil C and N stocks either both increased or both decreased for most studies. Soil C and N sequestration were tightly linked, resulting in little change in C:N ratios with changes in management. Within grazing treatments N 2 O made a minor contribution to GWP (0.1-4%), but increases in N 2 O fluxes offset significant portions of C sequestration gains due to fertilization (10-125%) and conversion (average = 27%). Results from this work demonstrate that even when improved management practices result in considerable rates of C and N sequestration, changes in N 2 O fluxes can offset a substantial portion of gains by C sequestration. Even for cases in which C sequestration rates are not entirely offset by increases in N 2 O fluxes, small increases in N 2 O fluxes can substantially reduce C sequestration benefits. Conversely, reduction of N 2 O fluxes in grassland soils brought about by changes in management represents an opportunity to reduce the contribution of grasslands to net greenhouse gas forcing.

2025, Soil Science Society of America Journal

2000b). Tillage also increases aeration, which enhances C mineralization and CO 2 fluxes to the atmosphere (Elliott, Identification of diagnostic soil organic matter (SOM) fractions 1986; Reicosky and Lindstrom, 1993). and the mechanisms controlling their formation and turnover is critical for better understanding of C dynamics in soils. Enhanced micro-Several studies have elucidated the relationship beaggregate formation and stabilization of C due to reduced macro-tween aggregate and associated SOM dynamics (Elliott, aggregate turnover has been proposed as a mechanism promoting C

2025, Soil & Tillage Research

Long-term loss of soil C stocks under conventional tillage and accrual of soil C following adoption of no-tillage have been well documented. No-tillage use is spreading, but it is common to occasionally till within a no-till regime or to regularly alternate between till and no-till practices within a rotation of different crops. Short-term studies indicate that substantial amounts of C can be lost from the soil immediately following a tillage event, but there are few field studies that have investigated the impact of infrequent tillage on soil C stocks. How much of the C sequestered under no-tillage is likely to be lost if the soil is tilled? What are the longer-term impacts of continued infrequent no-tillage? If producers are to be compensated for sequestering C in soil following adoption of conservation tillage practices, the impacts of infrequent tillage need to be quantified. A few studies have examined the short-term impacts of tillage on soil C and several have investigated the impacts of adoption of continuous no-tillage. We present: (1) results from a modeling study carried out to address these questions more broadly than the published literature allows, (2) a review of the literature examining the short-term impacts of tillage on soil C, (3) a review of published studies on the physical impacts of tillage and (4) a synthesis of these components to assess how infrequent tillage impacts soil C stocks and how changes in tillage frequency could impact soil C stocks and C sequestration. Results indicate that soil C declines significantly following even one tillage event (1-11% of soil C lost). Longer-term losses increase as frequency of tillage increases. Model analyses indicate that cultivating and ripping are less disruptive than moldboard plowing, and soil C for those treatments average just 6% less than continuous NT compared to 27% less for CT. Most (80%) of the soil C gains of NT can be realized with NT coupled with biannual cultivating or ripping.

2025, Soil Biology & Biochemistry

Soil disturbance from tillage is a major cause of organic matter depletion and reduction in the number and stability of soil aggregates when native ecosystems are converted to agriculture. No-till (NT) cropping systems usually exhibit increased aggregation and soil organic matter relative to conventional tillage (CT). However, the extent of soil organic matter changes in response to NT management varies between soils and the mechanisms of organic matter stabilization in NT systems are unclear. We evaluated a conceptual model which links the turnover of aggregates to soil organic matter dynamics in NT and CT systems; we argue that the rate of macroaggregate formation and degradation (i.e. aggregate turnover) is reduced under NT compared to CT and leads to a formation of stable microaggregates in which carbon is stabilized and sequestered in the long term. Therefore, the link between macroaggregate turnover, microaggregate formation, and C stabilization within microaggregates partly determines the observed soil organic matter increases under NT.

2025, Environmental Management

Estimates of potential and actual C sequestration require areal information about various types of management activities. Forest surveys, land use data, and agricultural statistics contribute information enabling calculation of the impacts of current and historical land management on C sequestration in biomass (in forests) or in soil (in agricultural systems). Unfortunately little information exists on the distribution of various management activities that can impact soil C content in grassland systems. Limited information of this type restricts our ability to carry out bottom-up estimates of the current C balance of grasslands or to assess the potential for grasslands to act as C sinks with changes in management. Here we review currently available information about grassland management, how that information could be related to information about the impacts of management on soil C stocks, information that may be available in the future, and needs that remain to be filled before in-depth assessments may be carried out. We also evaluate constraints induced by variability in information sources within and between countries.It is readily apparent that activity data for grassland management is collected less frequently and on a coarser scale than data for forest or agricultural inventories and that grassland activity data cannot be directly translated into IPCC-type factors as is done for IPCC inventories of agricultural soils. However, those management data that are available can serve to delineate broad-scale differences in management activities within regions in which soil C is likely to change in response to changes in management. This, coupled with the distinct possibility of more intensive surveys planned in the future, may enable more accurate assessments of grassland C dynamics with higher resolution both spatially and in the number management activities. Local, regional, national, and international inventories of C sequestration (actual and potential) generally

2025

The Shortgrass Steppe Long Term Ecological Research (SGS-LTER) project is entering its final year of a more than 30-year history (1982-2014) of research and engagement within the LTER network. During this transition we are simultaneously bringing closure to several of our experiments and expanding our infrastructure in the field to position our community of scientists for future work. New initiatives and infrastructure include the following: 1) a common garden experiment to assess the genetic plasticity and response of the dominant grass species, Bouteloua gracilis, to climate change. Field collections were made for our common garden experiment in 2011 and representative plants will be installed at the new SGS Research and Interpretation Center garden this fall; 2) A new grazing experiment designed to investigate the response of shortgrass steppe plant communities (e.g., species composition and abundance) to changing climate and grazer populations; and 3) New rainout shelters to understand more fully responses of the plant and microbial communities to changes in rainfall frequency and abundance. In addition to new science initiatives, our information management team is creating an extensive digital archive of our experimental data and metadata collected during our tenure with the LTER Network, but also undertaking an ambitious effort to capture the history of how and why experimental protocols have changed.

2025, Biology and Fertility of Soils

2025

Many firms anticipate that a cap on greenhouse gas emissions will eventually be imposed, either through an international agreement like the Kyoto protocol or through domestic policy, and have started to take voluntary actions to reduce their emissions. If agricultural producers participate in the emerging market for tradable C-credits, it must be possible to verify that actions farmers take do increase the amount of C in soils and this increase can be maintained over the length of the contract. In this paper we develop a prototype measurement and monitoring scheme for C-credits sequestered in agricultural soils and estimate its costs for the small grain-producing region of Montana using an econometric-process simulation model. Three key results emerge from the prototype framework. First, the efficiency of measurement and monitoring procedures for agricultural soil C sequestration depends on the price of C credits. Second, we find that at all price levels, costs of measuring and moni...

2025

This study develops an integrated assessment approach for analysis of the economic potential for carbon sequestration in agricultural soils. By linking a site-specific economic simulation model of agricultural production to a crop ecosystem model, the approach shows the economic efficiency of soil carbon (C) sequestration depends on site-specific opportunity costs of changing production practices and rates of soil C sequestration. An application is made to the dryland grain production systems of the U.S. Northern Plains which illustrates the sensitivity of the sequestration costs to policy design. The marginal cost of soil C ranges from 12to12 to 12to500 per metric ton depending upon the type of contract or payment mechanism used, the amount of carbon sequestered, and the site-specific characteristics of the areas.

2025

Under the Kyoto protocol of the United Nations Framework Convention on Climate Change the United States is charged with reducing emissions of greenhouse gases to seven percent below their 1990 levels by the period 2008-2012. These reductions could be met from many industries including agriculture. In this paper, an economic simulation model is linked to the CENTURY ecosystem model to quantify the economic efficiency of policies that might be used to sequester carbon (C) in agricultural soils in the Northern Great Plains region. Model outputs are combined to assess the costs of inducing changes in equilibrium levels of soil C through three types of policies. The first is a CRP-style policy that provides producers with per-acre payments for converting crop-land to permanent grass; the second is a policy that provides per-acre payments to all farmers that use continuous cropping, regardless of the land's cropping history; the third is a policy that provides per-acre payments for th...

2025, Plant and Soil

The relationship between soil structure and the ability of soil to stabilize soil organic matter (SOM) is a key element in soil C dynamics that has either been overlooked or treated in a cursory fashion when developing SOM models. The purpose of this paper is to review current knowledge of SOM dynamics within the framework of a newly proposed soil C saturation concept. Initially, we distinguish SOM that is protected against decomposition by various mechanisms from that which is not protected from decomposition. Methods of quantification and characteristics of three SOM pools defined as protected are discussed. Soil organic matter can be: (1) physically stabilized, or protected from decomposition, through microaggregation, or (2) intimate association with silt and clay particles, and (3) can be biochemically stabilized through the formation of recalcitrant SOM compounds. In addition to behavior of each SOM pool, we discuss implications of changes in land management on processes by wh...

2025, SSSA Special Publication

2025, Climatic Change

Soil carbon sequestration has been suggested as a means to help mitigate atmospheric CO2 increases, however there is limited knowledge aboutthe magnitude of the mitigation potential. Field studies across the U.S. provide information on soil C stock changes that result from changes in agricultural management. However, data from such studies are not readily extrapolated to changes at a national scale because soils, climate, and management regimes vary locally and regionally. We used a modified version of the Intergovernmental Panel on Climate Change (IPCC) soil organic C inventory method, together with the National Resources Inventory (NRI) and other data, to estimate agricultural soil C sequestration potential in the conterminous U.S. The IPCC method estimates soil C stock changes associated with changes in land use and/or land management practices. In the U.S., the NRI provides a detailed record of land use and management activities on agricultural land that can be used to implement...

2025, Soil Science Society of America Journal