scholarly journals There and back again, an organic carbon journey: mapping pathways and loops

2021 ◽  
Author(s):  
Maike Iris Esther Scheffold ◽  
Inga Hense
Keyword(s):  
Organic Carbon ◽  
Spatial Scales ◽  
Qualitative Model ◽  
Marine Systems ◽  
Additional Tool ◽  
General Pathway ◽  
Marine System ◽  
The Impact ◽  
Embedded Process

Abstract. Understanding and determining where organic carbon (OC) ends up in the ocean and how long it remains there is one of the most pressing tasks of our time, as the fate of OC in the ocean links to the climate system. To provide an additional tool to accomplish this and other related tasks, we map and conceptualize OC pathways in a qualitative model. The model is complementary to existing concepts of OC processes and pathways which are based mainly on quantifications and observations of current states and dominant processes. Our model, on the contrary, presents general pathway patterns and embedded processes without focusing on dominant processes or pathways or omitting rare ones. By mapping, comparing, and condensing pathways and involved spatial scales, we define three remineralization and two recalcitrant dissolved organic carbon loops that close within the marine systems. Pathways that exit the marine system comprise inorganic atmospheric, OC atmospheric, and long-term sediment loops. With the defined loops and the embedded process options, the model is flexible and can be adapted to different systems, changing understanding or changing mechanisms. As such, it can help tracking pathway changes and assessing the impact of human interventions on pathways, marine ecosystems, and the oceanic organic carbon cycle.

Modelling long-term soil organic carbon dynamics under the impact of land cover change and soil redistribution

CATENA ◽  
2017 ◽  
Vol 151 ◽  
pp. 63-73 ◽  
Author(s):  
Samuel Bouchoms ◽  
Zhengang Wang ◽  
Veerle Vanacker ◽  
Sebastian Doetterl ◽  
Kristof Van Oost
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Land Cover ◽  
Land Cover Change ◽  
Carbon Dynamics ◽  
Soil Redistribution ◽  
The Impact ◽  
Soil Organic Carbon Dynamics

Impact of Long-Term Organic Fertilizer Application on Lignin in Mollisol

2010 ◽  
Vol 113-116 ◽  
pp. 1332-1335 ◽  
Author(s):  
Ning Liu ◽  
Hong Bo He ◽  
Hong Tu Xie ◽  
Zhen Bai ◽  
Xu Dong Zhang
Keyword(s):  
Organic Carbon ◽  
Organic Fertilizer ◽  
Fertilizer Application ◽  
Carbon Pools ◽  
Organic Fertilization ◽  
Degradation Degree ◽  
Northeast Of China ◽  
The Impact ◽  
Cuo Oxidation

Fertilization is one of the essential managements to maintain and increase soil organic carbon (SOC) level in agroecosystems. It has been realized that fertilizer applications influenced the turnover of labile and refractory organic carbon pools in arable soil markedly. However, the dynamic of relatively refractory lignin in response to fertilization is still kept unclear. Therefore, the impact of long-term organic fertilization on the content and degradation degree of lignin in Mollisol was investigated. Lignin monomers were released by alkaline CuO oxidation method and quantified by gas chromatography (GC). At the time scale of decades, lignin was clearly accumulated in soil and the relative accumulation of lignin in SOC was evident after long-term organic fertilizer application. Compared with the unfertilized soil, lower acid to aldehyde ratios of vanillyl and syringyl units induced by organic fertilization suggested a lower degradation degree of lignin incorporated into soil to some extent. It could be concluded that long-term organic fertilization was an effective fertilizer practice for lignin accumulation in soil and SOC sequestration in Mollisol in northeast of China.

scholarly journals Long-Term Biosolids Application on Land: Beneficial Recycling of Nutrients or Eutrophication of Agroecosystems?

Soil Systems ◽  
2022 ◽  
Vol 6 (1) ◽  
pp. 9
Author(s):  
Murray B. McBride
Keyword(s):  
Trace Metals ◽  
Organic Carbon ◽  
Nutrient Loading ◽  
Agricultural Soils ◽  
Soil Health ◽  
Water Soluble ◽  
Amended Soils ◽  
The Impact ◽  
Biosolids Application

The impact of repeated application of alkaline biosolids (sewage sludge) products over more than a decade on soil concentrations of nutrients and trace metals, and potential for uptake of these elements by crops was investigated by analyzing soils from farm fields near Oklahoma City. Total, extractable (by the Modified Morgan test), and water-soluble elements, including macronutrients and trace metals, were measured in biosolids-amended soils and, for comparison, in soils that had received little or no biosolids. Soil testing showed that the biosolids-amended soils had higher pH and contained greater concentrations of organic carbon, N, S, P, and Ca than the control soils. Soil extractable P concentrations in the biosolids-amended soils averaged at least 10 times the recommended upper limit for agricultural soils, with P in the amended soils more labile and soluble than the P in control soils. Several trace elements (most notably Zn, Cu, and Mo) had higher total and extractable concentrations in the amended soils compared to the controls. A radish plant assay revealed greater phytoavailability of Zn, P, Mo, and S (but not Cu) in the amended soils. The excess extractable and soluble P in these biosolids-amended soils has created a long-term source of slow-release P that may contribute to the eutrophication of adjacent surface waters and contamination of groundwater. While the beneficial effects of increased soil organic carbon on measures of “soil health” have been emphasized in past studies of long-term biosolids application, the present study reveals that these benefits may be offset by negative impacts on soils, crops, and the environment from excessive nutrient loading.

scholarly journals SUSTAINABLE AGRICULTURE MANAGEMENTS TO CONTROL SOIL EROSION

2021 ◽  
Author(s):  
Artemi Cerdà ◽  
Enric Terol
Keyword(s):  
Soil Erosion ◽  
Sustainable Agriculture ◽  
Spatial Scales ◽  
Low Frequency ◽  
Traditional Management ◽  
Erosion Rates ◽  
Olive Groves ◽  
Simulated Rain ◽  
The Impact

High rates of soil erosion compromise sustainable agriculture. In rainfed agricultural fields, erosion rates several orders ofmagnitude higher than the erosion rates considered tolerable have been quantified. In Mediterranean rainfed crops suchas vineyards, almonds and olive groves, and in the new sloping citrus and persimmon plantations, the rates of soil lossmake it necessary to apply measures to reduce them to avoid collapse in agricultural production. Managements such asweeds, catch crops and mulches (straw and pruning remains) are viable options to achieve sustainability. This work appliesmeasurements through plots, simulated rainfall experiments and ISUM (Improved Stock-Unearhing method) to quantifythe loss of soil at different temporal and spatial scales in fields of traditional management (herbicide or tillage) and underalternative management (mulches and plant covers). The work carried out at the experimental station for the study of soilerosion in the Sierra de Enguera and those of Montesa and Les Alcusses provide information on erosion plots undernatural rain. Experiments carried out with simulated rain in fields of olive, almond, citrus, persimmon, vineyard and fruittrees report the hydrological and erosive response under low frequency and high intensity rains. And finally, the ISUMtopographic method report the impact of long-term management, from the plantation. The results indicate that the loss ofsoil is greater (x10-1000) in soils under traditional management (tillage and herbicide) due to the fact that they remain barefor most of the year. The use of straw mulch immediately reduces soil erosion by two orders of magnitude. Also mulchesfrom chipped pruned branches remains are very efficient but require more years to reduce soil loss. Weeds and catchcrops are very efficient in controlling erosion.

The Contribution of Microorganisms to Soil Organic Carbon Stock Under Fertilization Varies among Aggregate Size Classes

2021 ◽  
Author(s):  
Jinjing Lu ◽  
Shengping Li ◽  
Guopeng Liang ◽  
Xueping Wu ◽  
Qiang Zhang ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Microbial Community ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Aggregate Size ◽  
Community Diversity ◽  
C Storage ◽  
C Stock ◽  
The Impact

Abstract Long term fertilization alters soil microbiological properties and then affects soil organic carbon (SOC) stocks. However, the interrelations of SOC with biological drivers and their relative importance are rarely analyzed quantitatively at aggregate scale. We investigated the contribution of soil microbial biomass, diversity and enzyme activity to C stock in soil aggregate fractions (> 5 mm, 2 − 5 mm, 1 − 2 mm, 0.25 − 1 mm and < 0.25 mm) at topsoil (0–15 cm) from 27-year long term fertilization regime. Compared to CK (no fertilization management), NPS and NPM (inorganic fertilization plus the incorporation of maize straw or composted cow manure) significantly reduced the impact of NP (inorganic fertilizers application alone) on the growth of microbial community, and increased the microbial contribution to C stock. The results showed that microbial variables were significantly correlated with SOC content in > 0.25 mm aggregates rather than in < 0.25 mm aggregates. Fungal variables (fungal, AM biomass, and F/B ratio) and enzyme activities (BXYL and LAP) in > 0.25 mm aggregates explained 21% and 2% on C, respectively. Overall, organic matter (OM) addition could contribute to higher C storage by boosting fungal community and enzyme activity rather than by changing microbial community diversity in macro-aggregates.

scholarly journals Rapidly increasing macroalgal cover not related to herbivorous fishes on Mesoamerican reefs

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2084 ◽  
Author(s):  
Adam Suchley ◽  
Melanie D. McField ◽  
Lorenzo Alvarez-Filip
Keyword(s):  
Coral Reef ◽  
Coral Cover ◽  
Spatial Scales ◽  
Herbivorous Fish ◽  
Primary Role ◽  
Macroalgal Cover ◽  
Control Paradigm ◽  
The Caribbean ◽  
The Impact

Long-term phase shifts from coral to macroalgal dominated reef systems are well documented in the Caribbean. Although the impact of coral diseases, climate change and other factors is acknowledged, major herbivore loss through disease and overfishing is often assigned a primary role. However, direct evidence for the link between herbivore abundance, macroalgal and coral cover is sparse, particularly over broad spatial scales. In this study we use a database of coral reef surveys performed at 85 sites along the Mesoamerican Reef of Mexico, Belize, Guatemala and Honduras, to examine potential ecological links by tracking site trajectories over the period 2005–2014. Despite the long-term reduction of herbivory capacity reported across the Caribbean, the Mesoamerican Reef region displayed relatively low macroalgal cover at the onset of the study. Subsequently, increasing fleshy macroalgal cover was pervasive. Herbivorous fish populations were not responsible for this trend as fleshy macroalgal cover change was not correlated with initial herbivorous fish biomass or change, and the majority of sites experienced increases in macroalgae browser biomass. This contrasts the coral reef top-down herbivore control paradigm and suggests the role of external factors in making environmental conditions more favourable for algae. Increasing macroalgal cover typically suppresses ecosystem services and leads to degraded reef systems. Consequently, policy makers and local coral reef managers should reassess the focus on herbivorous fish protection and consider complementary measures such as watershed management in order to arrest this trend.

scholarly journals Differential long-term effects of climate change and management on stocks and distribution of soil organic carbon in productive grasslands

2012 ◽  
Vol 9 (1) ◽  
pp. 1055-1096 ◽  
Author(s):  
A. M. G. De Bruijn ◽  
P. Calanca ◽  
C. Ammann ◽  
J. Fuhrer
Keyword(s):  
Climate Change ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Climate Change Scenarios ◽  
Long Term Effects ◽  
Organic C ◽  
Soil C ◽  
The Impact ◽  
Soc Stocks

Abstract. We studied the impact of climate change on the dynamics of soil organic carbon (SOC) stocks in productive grassland systems undergoing two types of management, an intensive type with frequent harvests and fertilizer applications and an extensive system where fertilization is omitted and harvests are fewer. The Oensingen Grassland Model was explicitly developed for this study. It was calibrated using measurements taken in a recently established permanent sward in Central Switzerland, and run to simulate SOC dynamics over 2001–2100 under three climate change scenarios assuming different elements of IPCC A2 emission scenarios. We found that: (1) management intensity dominates SOC until approximately 20 yr after grassland establishment. Differences in SOC between climate scenarios become significant after 20 yr and climate effects dominate SOC dynamics from approximately 50 yr after establishment, (2) carbon supplied through manure contributes about 60% to measured organic C increase in fertilized grassland. (3) Soil C accumulates particularly in the top 10 cm soil until 5 yr after establishment. In the long-term, C accumulation takes place in the top 15 cm of the soil profile, while C content decreases below this depth. The transitional depth between gains and losses of C mainly depends on the vertical distribution of root senescence and root biomass. We discuss the importance of previous land use on carbon sequestration potentials that are much lower at the Oensingen site under ley-arable rotation and with much higher SOC stocks than most soils under arable crops. We further discuss the importance of biomass senescence rates, because C balance estimations indicate that these may differ considerably between the two management systems.

scholarly journals Measuring and Monitoring the Impact of Precision Land Levelling and Arable Cropping Systems on Aggregate Associated Carbon Fractions and Soil Carbon Stock in Sub-tropical Ecosystems

2020 ◽  
pp. 197-220
Author(s):  
R. K. Naresh ◽  
Yogesh Kumar ◽  
S. S. Tomar ◽  
Mukesh Kumar ◽  
M. Sharath Chandra ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Irrigation Water ◽  
Cropping Systems ◽  
Cropping System ◽  
Energy Productivity ◽  
Tropical Ecosystems ◽  
Carbon Fractions ◽  
The Impact

The Long term experiment (2009-10 to-2018-19) was conducted to study the effects of precision land levelled (PLL) versus traditional land levelled (TLL) systems on aggregate-associated soil organic carbon (SOC) in a farmers participatory fields under sub-tropical ecosystems (Western Uttar Pradesh) of Indian conditions. The significance of this study mainly focus to determine the suitability of various labile carbon fractions as indicators of soil quality and the stability of aggregates plays a vital role in preserving and long term storing of soil organic carbon by implementing Precision Land Levelling under various arable cropping system. The treatment comprised of sixteen alternative arable cropping systems strategies viz. R-WPLL, R-WTLL, S-WPLL, S-WTLL, R-P-MbPLL, R-P-MbTLL, R-P-OPLL, R-P-OTLL, R-C-OPLL, R-C-OTLL, O-W-MbPLL, O-W-MbTLL, M-W-MbPLL, M-W-MbTLL, M-P-MbPLL, and M-P-MbTLL etc were taken with recommended dose of fertilizers and various observations were recorded. The results indicated that the M-P-MbPLL produced 79.5 kgha-1day-1 productivity and used only 110 cm irrigation water which was 48.1 per cent less than irrigation water used for R-WPLL. The land use efficiency under R-P-MbPLL, R-P-OPLL, R-P-MbPLL, R-C-OPLL and M-P-MbPLL were recorded as 86.2, 85.1, 84.8, 84.6 and 83.9%. However, energy value in terms total input energy and energy productivity were 39.9 and 218.5 GJ ha-1 over existing R-W system (32.9 & 105.7 GJ ha-1). The quantity of water used in the R-C-O, M-W-Mb, M-P-Mb, and O-W-Mb were 46.1, 44.9, 40.1 and 36.3 per cent less than quantity of water used for R-W system. Aggregate-associated SOC contents in 0-15 cm depth were recorded highest SOC at 15-30 cm depth in PLL systems as 9.4% for both M-P-MbPLL and M-W-MbPLL. Highest PON change in arable cropping system (30.9 & 40.1%) was found in O-W-Mb with precision land levelling (T11) plots followed by R-P-O with precision land levelling (T7) plots (26.1 & 35.8%) as compared to R-W and S-W system. The values of LFOC in surface soil were 194.7, 187.9, 176.2, 170.9, 168.5, 150.6, 132.8 and 123.8 mgkg−1 in R-P-O, R-C-O, M-W-Mb, O-W-Mb, M-P-Mb, R-P-Mb, R-W and S-W with precision land levelling treatments. Higher SOC sequestration was observed with precision land leveling along with alternative arable cropping systems with O-W-MbPLL, R-C-OPLL, R-P-OPLL, O-W-MbPLL and M-P-MbPLL respectively. Therefore, PLL systems had greater soil surface aggregation and carbon storage, land levelling did not affect SOC patterns across aggregates, but changed the distribution of aggregate size, reflecting that land levelling mainly influenced soil fertility by altering soil structure.

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