scholarly journals Fluvial organic carbon cycling regulated by sediment transit time and mineral protection

2021 ◽  
Author(s):  
Marisa Repasch ◽  
Joel S. Scheingross ◽  
Niels Hovius ◽  
Maarten Lupker ◽  
Hella Wittmann ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Transit Time ◽  
Management Practices ◽  
River Channels ◽  
Channel Mobility ◽  
River Modelling ◽  
Organic Carbon Cycling ◽  
Lateral Erosion ◽  
Global Carbon

AbstractRivers transfer terrestrial organic carbon (OC) from mountains to ocean basins, playing a key role in the global carbon cycle. During fluvial transit, OC may be oxidized and emitted to the atmosphere as CO2 or preserved and transported to downstream depositional sinks. The balance between oxidation and preservation determines the amount of particulate OC (POC) that can be buried long term, but the factors regulating this balance are poorly constrained. Here, we quantify the effects of fluvial transit on POC fluxes along an ~1,300 km lowland channel with no tributaries. We show that sediment transit time and mineral protection regulate the magnitude and rate of POC oxidation, respectively. Using a simple turnover model, we estimate that annual POC oxidation is a small percentage of the POC delivered to the river. Modelling shows that lateral erosion into POC-rich floodplains can increase POC fluxes to downstream basins, thereby offsetting POC oxidation. Consequently, rivers with high channel mobility can enhance CO2 drawdown while management practices that stabilize river channels may reduce the potential for CO2 drawdown.

scholarly journals Tracking Changes on Soil Structure and Organic Carbon Sequestration after 30 Years of Different Tillage and Management Practices

Agronomy ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 291
Author(s):  
Ramón Bienes ◽  
Maria Jose Marques ◽  
Blanca Sastre ◽  
Andrés García-Díaz ◽  
Iris Esparza ◽  
...  
Keyword(s):  
Triticum Aestivum ◽  
Organic Carbon ◽  
Management Practices ◽  
Management Strategies ◽  
Triticum Aestivum L ◽  
Field Trials ◽  
Conventional Tillage ◽  
Soil Parameters ◽  
Wilting Point

Long-term field trials are essential for monitoring the effects of sustainable land management strategies for adaptation and mitigation to climate change. The influence of more than thirty years of different management is analyzed on extensive crops under three tillage systems, conventional tillage (CT), minimum tillage (MT), and no-tillage (NT), and with two crop rotations, monoculture winter-wheat (Triticum aestivum L.) and wheat-vetch (Triticum aestivum L.-Vicia sativa L.), widely present in the center of Spain. The soil under NT experienced the largest change in organic carbon (SOC) sequestration, macroaggregate stability, and bulk density. In the MT and NT treatments, SOC content was still increasing after 32 years, being 26.5 and 32.2 Mg ha−1, respectively, compared to 20.8 Mg ha−1 in CT. The SOC stratification (ratio of SOC at the topsoil/SOC at the layer underneath), an indicator of soil conservation, increased with decreasing tillage intensity (2.32, 1.36, and 1.01 for NT, MT, and CT respectively). Tillage intensity affected the majority of soil parameters, except the water stable aggregates, infiltration, and porosity. The NT treatment increased available water, but only in monocropping. More water was retained at the permanent wilting point in NT treatments, which can be a disadvantage in dry periods of these edaphoclimatic conditions.

scholarly journals Effects of Management and Hillside Position on Soil Organic Carbon Stratification in Mediterranean Centenary Olive Grove

Agronomy ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 650
Author(s):  
Jesús Aguilera-Huertas ◽  
Beatriz Lozano-García ◽  
Manuel González-Rosado ◽  
Luis Parras-Alcántara
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Soil Quality ◽  
Management Practices ◽  
Soil Management ◽  
Olive Grove ◽  
No Tillage ◽  
Short Term ◽  
Degradation Degree

The short- and medium—long-term effects of management and hillside position on soil organic carbon (SOC) changes were studied in a centenary Mediterranean rainfed olive grove. One way to measure these changes is to analyze the soil quality, as it assesses soil degradation degree and attempts to identify management practices for sustainable soil use. In this context, the SOC stratification index (SR-COS) is one of the best indicators of soil quality to assess the degradation degree from SOC content without analyzing other soil properties. The SR-SOC was calculated in soil profiles (horizon-by-horizon) to identify the best soil management practices for sustainable use. The following time periods and soil management combinations were tested: (i) in the medium‒long-term (17 years) from conventional tillage (CT) to no-tillage (NT), (ii) in the short-term (2 years) from CT to no-tillage with cover crops (NT-CC), and (iii) the effect in the short-term (from CT to NT-CC) of different topographic positions along a hillside. The results indicate that the SR-SOC increased with depth for all management practices. The SR-SOC ranged from 1.21 to 1.73 in CT0, from 1.48 to 3.01 in CT1, from 1.15 to 2.48 in CT2, from 1.22 to 2.39 in NT-CC and from 0.98 to 4.16 in NT; therefore, the soil quality from the SR-SOC index was not directly linked to the increase or loss of SOC along the soil profile. This demonstrates the time-variability of SR-SOC and that NT improves soil quality in the long-term.

Influence of agricultural management on soil organic carbon: A compendium and assessment of Canadian studies

2003 ◽  
Vol 83 (4) ◽  
pp. 363-380 ◽  
Author(s):  
A. J. VandenBygaart ◽  
E. G. Gregorich ◽  
D. A. Angers
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Management Practices ◽  
Agricultural Management ◽  
Organic Fertilizers ◽  
Published Data ◽  
Native Land ◽  
Soc Stocks ◽  
Long Term Studies

To fulfill commitments under the Kyoto Protocol, Canada is required to provide verifiable estimates and uncertainties for soil organic carbon (SOC) stocks, and for changes in those stocks over time. Estimates and uncertainties for agricultural soils can be derived from long-term studies that have measured differences in SOC between different management practices. We compiled published data from long-term studies in Canada to assess the effect of agricultural management on SOC. A total of 62 studies were compiled, in which the difference in SOC was determined for conversion from native land to cropland, and for different tillage, crop rotation and fertilizer management practices. There was a loss of 24 ± 6% of the SOC after native land was converted to agricultural land. No-till (NT) increased the storage of SOC in western Canada by 2.9 ± 1.3 Mg ha-1; however, in eastern Canada conversion to NT did not increase SOC. In general, the potential to store SOC when NT was adopted decreased with increasing background levels of SOC. Using no-tillage, reducing summer fallow, including hay in rotation with wheat (Triticum aestivum L.), plowing green manures into the soil, and applying N and organic fertilizers were the practices that tended to show the most consistent in creases in SOC storage. By relating treatment SOC levels to those in the control treatments, SOC stock change factors and their levels of uncertainty were derived for use in empirical models, such as the United Nations Intergovernmental Panel on Climate Change (IPCC). Guidelines model for C stock changes. However, we must be careful when attempting to extrapolate research plot data to farmers’ fields since the history of soil and crop management has a significant influence on existing and future SOC stocks. Key words: C sequestration, tillage, crop rotations, fertilizer, cropping intensity, Canada

Effect of forest management on the formation and stability of phytolith and PhytOC in forest ecosystem

2021 ◽  
Author(s):  
Lin Xu ◽  
Yongjun Shi ◽  
Wanjie Lv ◽  
Zhengwen Niu ◽  
Ning Yuan ◽  
...  
Keyword(s):  
Carbon Sequestration ◽  
Forest Management ◽  
Forest Ecosystem ◽  
Management Practices ◽  
Forest Ecosystems ◽  
Moso Bamboo ◽  
Soil System ◽  
Silicon Fertilization ◽  
Global Carbon

<p>Forest ecosystem has a high carbon sequestration capacity and plays a crucial role in maintaining global carbon balance and climate change. Phytolith-occluded carbon (PhytOC), a promising long-term biogeochemical carbon sequestration mechanism, has attracted more attentions in the global carbon cycle and the regulation of atmospheric CO<sub>2</sub>. Therefore, it is of practical significance to investigate the PhytOC accumulation in forest ecosystems. Previous studies have mostly focused on the estimation of the content and storage of PhytOC, while there were still few studies on how the management practices affect the PhytOC content. Here, this study focused on the effects of four management practices (compound fertilization, silicon fertilization, cut and control) on the increase of phytolith and PhytOC in Moso bamboo forests. We found that silicon fertilization had a greater potential to significantly promote the capacity of carbon sequestration in Moso bamboo forests. this finding positively corresponds recent studies that the application of silicon fertilizers (e.g., biochar) increase the Si uptake<strong><sup>1</sup></strong> to promote phytolith accumulation and its PhytOC sequestration in the plant-soil system<strong><sup>2</sup></strong>. Of course, the above-mentioned document<strong><sup>2</sup></strong> also had their own shortcomings, i.e., the experimental research time was not long, lacking long-term follow-up trial and the bamboo forest parts were also limited, so that the test results lack certain reliability. We have set up a long-term experiment plot to study the effects of silicon fertilizer on the formation and stability of phytolith and PhytOC in Moso bamboo forests. But anyway, different forest management practices, especially the application of high-efficiency silicon-rich fertilizers<strong><sup>1</sup></strong>, may be an effective way to increase the phytolith and PhytOC storage in forest ecosystems, and thereby improve the long-term CO<sub>2 </sub>sequestration capacity of forest ecosystems. Research in this study provides a good "forest plan" to achieve their national voluntary emission reduction commitments and achieves carbon neutrality goals for all over the world.</p><p>Refences:</p><p><sup>1</sup>Li et al., 2019. Plant and soil, 438(1-2), pp.187-203.</p><p><sup>2</sup>Huang et al., 2020, Science of The Total Environment, 715, p.136846.</p>

scholarly journals Total and Active Soil Organic Carbon from Long‐term Agricultural Management Practices in West Tennessee

ael ◽  
2019 ◽  
Vol 4 (1) ◽  
pp. 180062 ◽  
Author(s):  
Sindhu Jagadamma ◽  
Michael E. Essington ◽  
Sutie Xu ◽  
Xinhua Yin
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Management Practices ◽  
Agricultural Management ◽  
West Tennessee

Simulations of greenhouse gas emissions and soil organic carbon with ECOSSE for a rice field in Northern Italy

2020 ◽  
Author(s):  
Matthias Kuhnert ◽  
Viktoria Oliver ◽  
Andrea Volante ◽  
Stefano Monaco ◽  
Yit Arn Teh ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Management Practices ◽  
Ghg Emissions ◽  
Gas Emissions ◽  
Model Experiments ◽  
Below Ground

<p>Rice cultivation has high water consumption and emits large quantities of greenhouse gases. Therefore, rice fields provide great potential to mitigate GHG emissions by modifications to cultivation practices or external inputs. Previous studies showed differences for impacts of alternated wetting and drying (AWD) practices for above-ground and below-ground biomass, which might have long term impacts on soil organic carbon stocks. The objective of this study is to parameterise and evaluate the model ECOSSE for rice simulations based on data from an Italian rice test site where the effects of different water management practices and 12 common European cultivars, on yield and GHG emissions, were investigated. Special focus is on the differences of the impacts on the greenhouse gas emissions for AWD and continuous flooding (CF). The model is calibrated and tested for field measurements and is used for model experiments to explore climate change impacts and long-term effects. Long term carbon storage is of particular interest since it is a suitable mitigation strategy. As experiments showed different impacts of management practices on the below ground biomass, long term model experiments are used to estimate impacts on SOC of the different practices. The measurements also allow an analysis of the impacts of different cultivars and the uncertainty of model approaches using a single data set for calibration.</p>

scholarly journals Influence of cropping and fertilization on soil pore characteristics in a long-term field study

2020 ◽  
Author(s):  
David Nimblad Svensson ◽  
Jumpei Fukumasu ◽  
Gunnar Börjesson ◽  
John Koestel
Keyword(s):  
Organic Carbon ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Soil Structure ◽  
Management Practices ◽  
Pore Space ◽  
Pore Characteristics ◽  
Bare Fallow ◽  
Term Field

<p>Soil porosity, pore size distribution and pore characteristics such as connectivity are important for a range of soil processes including ease of root growth and air and water transport. The pore structure is therefore an important part of soil fertility. The pore space is sensitive to management practices such as tillage, fertilization and cropping. Understanding how these practices influence the pore space is important for maintaining a good soil structure that is well aerated and has sufficient drainage. X-ray computed tomography has become a widely used method for studying the pore space as it offers the advantage of enabling soil to be studied in its undisturbed form. In this study it was used to compare the effects of crop growth, tillage and N-fertilizing with Ca(NO3)<sub>2</sub> or farm yard manure (FYM). Soil samples were taken just below the surface from the long-term experiment in Ultuna, Sweden which was started in 1956. The bare fallow, FYM and Ca(NO3)<sub>2</sub>-treatment were sampled with minimum disturbance in two column sizes with inner diameters of 22.2 and 65.5 mm. Differences in pore space morphology were quantified and compared through pore size distribution and a range of connectivity measures, including the Euler number, the critical pore diameter and Gamma connectivity. Biopores were separated from non-biopores and their volume was quantified. Soil organic carbon was determined by dry combustion. Visible porosity and pores in the 150-500 µm class were significantly larger in the FYM and Ca(NO3)<sub>2</sub>-treatment compared to the bare fallow. The porosity occupied by biopores was not found to significantly differ between treatments but the biopores were found to have the largest diameters in the FYM-treatment. Despite that the organic carbon content was 1.7 times higher in the FYM compared to the Ca(NO3)<sub>2</sub>-treatment the visible porosity was similar. This may be due to the positive effects calcium has on the soil structure. The connectivity measures indicated that the FYM-treatment had the best connected pore networks. This may be partly due to the larger biopores. Ca(NO3)<sub>2</sub> showed to be a promising alternative to increase porosity. However, as all the management practices in the long-term field study are done by hand, future studies will have to investigate if the effect is equally similar to FYM under field conditions which are subject to heavy machineries.  </p>

scholarly journals Modelling of long-term Zn, Cu, Cd and Pb dynamics from soils fertilised with organic amendments

SOIL ◽  
2021 ◽  
Vol 7 (1) ◽  
pp. 107-123
Author(s):  
Claudia Cagnarini ◽  
Stephen Lofts ◽  
Luigi Paolo D'Acqui ◽  
Jochen Mayer ◽  
Roman Grüter ◽  
...  
Keyword(s):  
Sewage Sludge ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Management Practices ◽  
Farmyard Manure ◽  
Organic Amendments ◽  
Mineral Weathering ◽  
Lateral Mixing ◽  
Critical Limits

Abstract. Soil contamination by trace elements (TEs) is a major concern for sustainable land management. A potential source of excessive inputs of TEs into agricultural soils are organic amendments. Here, we used dynamic simulations carried out with the Intermediate Dynamic Model for Metals (IDMM) to describe the observed trends of topsoil Zn (zinc), Cu (copper), Pb (lead) and Cd (cadmium) concentrations in a long-term (>60-year) crop trial in Switzerland, where soil plots have been treated with different organic amendments (farmyard manure, sewage sludge and compost). The observed ethylenediaminetetraacetic acid disodium salt (EDTA)-extractable concentrations ranged between 2.6 and 27.1 mg kg−1 for Zn, 4.9 and 29.0 mg kg−1 for Cu, 6.1–26.2 mg kg−1 for Pb, and 0.08 and 0.66 mg kg−1 for Cd. Metal input rates were initially estimated based on literature data. An additional, calibrated metal flux, tentatively attributed to mineral weathering, was necessary to fit the observed data. Dissolved organic carbon fluxes were estimated using a soil organic carbon model. The model adequately reproduced the EDTA-extractable (labile) concentrations when input rates were optimised and soil lateral mixing was invoked to account for the edge effect of mechanically ploughing the trial plots. The global average root mean square error (RMSE) was 2.7, and the average bias (overestimation) was −1.66, −2.18, −4.34 and −0.05 mg kg−1 for Zn, Cu, Pb and Cd, respectively. The calibrated model was used to project the long-term metal trends in field conditions (without soil lateral mixing), under stable climate and management practices, with soil organic carbon estimated by modelling and assumed trends in soil pH. Labile metal concentrations to 2100 were largely projected to remain near constant or to decline, except for some metals in plots receiving compost. Ecotoxicological thresholds (critical limits) were predicted to be exceeded presently under sewage sludge inputs and to remain so until 2100. Ecological risks were largely not indicated in the other plots, although some minor exceedances of critical limits were projected to occur for Zn before 2100. This study advances our understanding of TEs' long-term dynamics in agricultural fields, paving the way to quantitative applications of modelling at field scales.

Effect of cropping practices on soil organic carbon: evidence from long-term field experiments in Victoria, Australia

Soil Research ◽  
2015 ◽  
Vol 53 (6) ◽  
pp. 636 ◽  
Author(s):  
Fiona Robertson ◽  
Roger Armstrong ◽  
Debra Partington ◽  
Roger Perris ◽  
Ivanah Oliver ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Management Practices ◽  
Field Experiments ◽  
Residue Management ◽  
Continuous Cropping ◽  
Zero Tillage ◽  
Stubble Retention ◽  
Soc Stocks

Despite considerable research, predicting how soil organic carbon (SOC) in grain production systems will respond to conservation management practices, such as reduced tillage, residue retention and alternative rotations, remains difficult because of the slowness of change and apparent site specificity of the effects. We compared SOC stocks (equivalent soil mass to ~0–0.3 m depth) under various tillage, residue management and rotation treatments in three long-term (12-, 28- and 94-year-old) field experiments in two contrasting environments (Mallee and Wimmera regions). Our hypotheses were that SOC stocks are increased by: (1) minimum tillage rather than traditional tillage; (2) continuous cropping, rather than crop–fallow rotations; and (3) phases of crop or pasture legumes in rotations, relative to continuous cropping with cereals. We found that zero tillage and stubble retention increased SOC in some circumstances (by up to 1.5 Mg C ha–1, or 8%) but not in others. Inclusion of bare fallow in rotations reduced SOC (by 1.4–2.4 Mg C ha–1, or 8–12%) compared with continuous cropping. Including a pulse crop (field pea, where the grain was harvested) in rotations also increased SOC in some instances (by ~6–8 Mg C ha–1, or 29–35%) but not in others. Similarly, leguminous pasture (medic or lucerne) phases in rotations either increased SOC (by 3.5 Mg C ha–1, or 21%) or had no significant effect compared with continuous wheat. Inclusion of a vetch green manure or unfertilised oat pasture in the rotation did not significantly increase SOC compared with continuous wheat. The responses in SOC to these management treatments were likely to be due, in part, to differences in nitrogen and water availability (and their effects on carbon inputs and decomposition) and, in part, to other, unidentified, interactions. We conclude that the management practices examined in the present study may not reliably increase SOC on their own, but that significant increases in SOC are possible under some circumstances through the long-term use of multiple practices, such as stubble retention + zero tillage + legume N input + elimination of fallow. The circumstances under which increases in SOC can be achieved require further investigation.

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