Effects of Steel Slag and Biochar Incorporation on Active Soil Organic Carbon Pools in a Subtropical Paddy Field

Industrial wastes and agricultural byproducts are increasingly used in crop production as fertilizers, but their impacts on soil carbon (C) sequestration remain poorly understood. The aim of this study was to examine the effects of applying steel slag (SS), biochar (B), and a combination of these two materials (SS + B) on total soil organic C (SOC), active SOC fractions, and C pool management index (CPMI) in a subtropical paddy field in China. The treatments were applied at a rate of 8 t ha−1 to rice at the two (early and late) crop seasons in 2015. The SOC concentrations in the top 30 cm soils in the SS + B treatments were 28.7% and 42.2% higher in the early and late crops, respectively, as compared to the controls (p < 0.05). SOC was positively correlated with soil C:N ratio across the two crop seasons (r = 0.92–0.97, p < 0.01). As compared to the control, SS + B treatment had significantly higher carbon pool index (CPI) in both early (22.4%) and late (40.1%) crops. In the early crop, the C pool activity index (CPAI) was significantly lower in B and SS + B treatments by over 50% than in the control, while the soil C pool management index (CPMI) in the SS, B, and SS + B treatments was lower than that in the control by 36.7%, 41.6%, and 45.4%, respectively. In contrast, in the late crop, no significant differences in CPAI and CPMI were observed among the treatments. Our findings suggest that the addition of steel slag and biochar in subtropical paddy fields could decrease active SOC pools and enhance soil C sequestration only in the early crop, but not the late crop.

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Manipulation of rhizosphere organisms to enhance glomalin production and C sequestration: Pitfalls and promises

Canadian Journal of Plant Science ◽

10.4141/cjps2013-146 ◽

2014 ◽

Vol 94 (6) ◽

pp. 1025-1032 ◽

Cited By ~ 11

Author(s):

F. L. Walley ◽

A. W. Gillespie ◽

Adekunbi B. Adetona ◽

J. J. Germida ◽

R. E. Farrell

Keyword(s):

Plant Growth ◽

Mycorrhizal Fungi ◽

Plant Growth Promoting Rhizobacteria ◽

C Sequestration ◽

Ionization Mass ◽

Edge Structure ◽

Organic C ◽

Soil C ◽

N Storage ◽

C And N

Walley, F. L., Gillespie, A. W., Adetona, A. B., Germida, J. J. and Farrell, R. E. 2014. Manipulation of rhizosphere organisms to enhance glomalin production and C-sequestration: Pitfalls and promises. Can. J. Plant Sci. 94: 1025–1032. Arbuscular mycorrhizal fungi (AMF) reportedly produce glomalin, a glycoprotein that has the potential to increase soil carbon (C) and nitrogen (N) storage. We hypothesized that interactions between rhizosphere microorganisms, such as plant growth-promoting rhizobacteria (PGPR), and AMF, would influence glomalin production. Our objectives were to determine the effects of AMF/PGPR interactions on plant growth and glomalin production in the rhizosphere of pea (Pisum sativum L.) with the goal of enhancing C and N storage in the rhizosphere. One component of the study focussed on the molecular characterization of glomalin and glomalin-related soil protein (GRSP) using complementary synchrotron-based N and C X-ray absorption near-edge structure (XANES) spectroscopy, pyrolysis field ionization mass spectrometry (Py-FIMS), and proteomics techniques to characterize specific organic C and N fractions associated with glomalin production. Our research ultimately led us to conclude that the proteinaceous material extracted, and characterized in the literature, as GRSP is not exclusively of AMF origin. Our research supports the established concept that GRSP is important to soil quality, and C and N storage, irrespective of origin. However, efforts to manipulate this important soil C pool will remain compromised until we more clearly elucidate the chemical nature and origin of this resource.

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Site-level simulations of measurable soil fractions with the Millennial V2 soil model

10.5194/egusphere-egu21-9795 ◽

2021 ◽

Author(s):

Rose Abramoff ◽

Bertrand Guenet ◽

Haicheng Zhang ◽

Katerina Georgiou ◽

Xiaofeng Xu ◽

...

Keyword(s):

C Sequestration ◽

Current Understanding ◽

Residence Times ◽

Century Model ◽

Mineral Association ◽

Organic C ◽

Soil C ◽

Soil Fractions ◽

Soil Model ◽

Mean Residence Times

<p>Soil carbon (C) models are used to predict C sequestration responses to climate and land use change. Yet, the soil models embedded in Earth system models typically do not represent processes that reflect our current understanding of soil C cycling, such as microbial decomposition, mineral association, and aggregation. Rather, they rely on conceptual pools with turnover times that are fit to bulk C stocks and/or fluxes. As measurements of soil fractions become increasingly available, it is necessary for soil C models to represent these measurable quantities so that model processes can be evaluated more accurately. Here we present Version 2 (V2) of the Millennial model, a soil model developed in 2018 to simulate C pools that can be measured by extraction or fractionation, including particulate organic C, mineral-associated organic C, aggregate C, microbial biomass, and dissolved organic C. Model processes have been updated to reflect the current understanding of mineral-association, temperature sensitivity and reaction kinetics, and different model structures were tested within an open-source framework. We evaluated the ability of Millennial V2 to simulate total soil organic C (SOC), as well as the mineral-associated and particulate fractions, using three independent data sets of soil fractionation measurements spanning a range of climate and geochemistry in Australia (N=495), Europe (N=176), and across the globe (N=716). Considering RMSE and AIC as indices of model performance, site-level evaluations show that Millennial V2 predicts soil organic carbon content better than the widely-used Century model, despite an increase in process complexity and number of parameters. Millennial V2 also reproduces between-site variation in SOC across gradients of climate, plant productivity, and soil type. By including the additional constraints of measured soil fractions, we can predict site-level mean residence times similar to a global distribution of mean residence times measured using SOC/respiration rate under an assumption of steady state. The Millennial V2 model updates the conceptual Century model pools and processes and represents our current understanding of the roles that microbial activity, mineral association and aggregation play in soil C sequestration.</p>

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Site-level simulations of measurable soil fractions with Millennial Version 2

10.5194/ismc2021-19 ◽

2021 ◽

Author(s):

Rose Abramoff ◽

Bertrand Guenet ◽

Haicheng Zhang ◽

Katerina Georgiou ◽

Xiaofeng Xu ◽

...

Keyword(s):

Meta Analysis ◽

C Sequestration ◽

Current Understanding ◽

Century Model ◽

Mineral Association ◽

Microbial Decomposition ◽

Organic C ◽

Soil C ◽

Soil Fractions ◽

C Stocks

<p>Soil carbon (C) models are used to predict C sequestration responses to climate and land use change. Yet, the soil models embedded in Earth system models typically do not represent processes that reflect our current understanding of soil C cycling, such as microbial decomposition, mineral association, and aggregation. Rather, they rely on conceptual pools with turnover times that are fit to bulk C stocks and/or fluxes. As measurements of soil fractions become increasingly available, soil C models that represent these measurable quantities can be evaluated more accurately. Here we present Version 2 (V2) of the Millennial model, a soil model developed to simulate C pools that can be measured by extraction or fractionation, including particulate organic C, mineral-associated organic C, aggregate C, microbial biomass, and dissolved organic C. Model processes have been updated to reflect the current understanding of mineral-association, temperature sensitivity and reaction kinetics, and different model structures were tested within an open-source framework. We evaluated the ability of Millennial V2 to simulate total soil organic C (SOC), as well as the mineral-associated and particulate fractions, using three soil fractionation data sets spanning a range of climate and geochemistry in Australia (N=495), Europe (N=176), and across the globe (N=730). Millennial V2 (RMSE = 1.98 &#8211; 4.76 kg, AIC = 597 &#8211; 1755) generally predicts SOC content better than the widely-used Century model (RMSE = 2.23 &#8211; 4.8 kg, AIC = 584 &#8211; 2271), despite an increase in process complexity and number of parameters. Millennial V2 reproduces between-site variation in SOC across a gradient of plant productivity, and predicts SOC turnover times similar to those of a global meta-analysis. Millennial V2 updates the conceptual Century model pools and processes and represents our current understanding of the roles that microbial activity, mineral association and aggregation play in soil C sequestration.</p>

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Quantifying total and labile pools of soil organic carbon in cultivated and uncultivated soils in eastern India

Soil Research ◽

10.1071/sr17188 ◽

2018 ◽

Vol 56 (4) ◽

pp. 413 ◽

Cited By ~ 2

Author(s):

Kumari Priyanka ◽

Anshumali

Keyword(s):

Land Use ◽

Function Analysis ◽

Land Use Changes ◽

C Sequestration ◽

Sensitivity Index ◽

Organic C ◽

Soil C ◽

C Pools ◽

The Impact ◽

Land Use Practices

Loss of labile carbon (C) fractions yields information about the impact of land-use changes on sources of C inputs, pathways of C losses and mechanisms of soil C sequestration. This study dealt with the total organic C (TOC) and labile C pools in 40 surface soil samples (0–15 cm) collected from four land-use practices: uncultivated sites and rice–wheat, maize–wheat and sugarcane agro-ecosystems. Uncultivated soils had a higher total C pool than croplands. The soil inorganic C concentrations were in the range of 0.7–1.4 g kg–1 under different land-use practices. Strong correlations were found between TOC and all organic C pools, except water-extractable organic C and mineralisable C. The sensitivity index indicated that soil organic C pools were susceptible to changes in land-use practices. Discriminant function analysis showed that the nine soil variables could distinguish the maize–wheat and rice–wheat systems from uncultivated and sugarcane systems. Finally, we recommend crop rotation practices whereby planting sugarcane replenishes TOC content in soils.

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Stratification of soil organic C, N and the C:N ratio as affected by different plastic film mulching modes in a semiarid region of China

Soil Research ◽

10.1071/sr18256 ◽

2019 ◽

Vol 57 (4) ◽

pp. 408 ◽

Cited By ~ 2

Author(s):

Peng Zhang ◽

Ting Wei ◽

Zhikuan Jia ◽

Xiaolong Ren

Keyword(s):

Crop Yields ◽

C:N Ratio ◽

Semiarid Region ◽

Plastic Film ◽

Organic C ◽

Soil C ◽

North West ◽

Plastic Film Mulching ◽

Film Mulching ◽

The Mean

The soil degradation caused by plastic film mulching tillage in rain-fed areas of north-west China is known to affect sustainable and stable crop yields because of major losses of soil organic carbon (SOC) and nutrients. To evaluate the effects of different plastic film mulching modes on SOC and total nitrogen (STN) sequestration capacity in loessic soil, we investigated the effects of different plastic film mulching on SOC, STN, and the soil C:N ratio in semiarid areas of southern Ningxia for a 4-year period (2013–2016). Five treatments were tested: (i) the control, conventional flat planting without mulching (CK); (ii) alternating mulching and bare rows without ridges and planting in mulched rows (P); (iii) furrow planting of maize, separated by consecutive plastic film-mulched ridges (S); (iv) furrow planting of maize, separated by alternating large and small plastic film-mulched ridges (D); and (v) furrow-flat planting of maize with a large plastic film-mulched ridge alternating with a flat plastic film-mulched space (R). In the final experimental year (2016), the results showed that the mean soil bulk density at 0–60 cm depth had decreased with film mulching treatments by 2.82%, 5.90% (P < 0.05), 7.29% (P < 0.05), and 9.46% (P < 0.05) respectively, compared with CK. Film mulching increased the concentration of SOC and STN, which were ranked in order S > R/D > P > CK; however, there was no significant increase with the storage of SOC and STN. The mean soil C:N ratio was higher with mulching treatment, i.e. 2.91% (P > 0.05) higher than CK in 0–60 cm depth. Mulching treatments significantly (P < 0.05) increased the stratification ratio (SR) of SOC and soil C: N ratio from the surface (0–20 cm) to all depths compared with CK, i.e. the SR of SOC at the 0–20:20–40 cm depth significantly (P < 0.05) increased with D, R, S, and P by 14.81%, 9.47%, 14.18%, and 9.51% respectively, compared with CK.

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A Complete Assessment of Carbon Stocks in Above and Belowground Biomass Components of a Hybrid Eucalyptus Plantation in Southern Brazil

Forests ◽

10.3390/f10070536 ◽

2019 ◽

Vol 10 (7) ◽

pp. 536 ◽

Cited By ~ 1

Author(s):

Márcio Viera ◽

Roque Rodríguez-Soalleiro

Keyword(s):

Belowground Biomass ◽

C Sequestration ◽

Fine Root Biomass ◽

Carbon Stocks ◽

High Rate ◽

Southern Brazil ◽

Organic C ◽

Soil C ◽

Eucalyptus Plantation ◽

Understory Biomass

Hybrid eucalypt clones are grown for fiber production worldwide and to provide an ecosystem service that can store atmospheric carbon at a very fast rate. This study assessed the carbon stocks in the soil and various tree fractions in a 10-year-old plantation of Eucalyptus urophylla S.T. Blake × Eucalyptus globulus Labill. in Southern Brazil. Four experimental plots were established, and an inventory of Eucalyptus trees was conducted by considering five diametric classes. Three trees in each diametric class were harvested for biomass and carbon quantification. The understory biomass of native trees was quantified in five subplots and the litter was quantified in 16 subplots. Organic C was quantified in the soil (SOC) and roots (diameter ≤ 0.5 cm) to a depth of 100 cm. The C concentration in the different biomass fractions of the eucalyptus trees were 55.7% (±0.6), 50.4% (±0.4), 49.5% (±0.6) and 45.4 % (±0.9) for leaves, branches, wood and bark, respectively. The C concentrations in the understory fractions were 51.4% (±1.0) for the canopy and 50.0% (±0.9) for the stem. The carbon concentration in the fine root biomass was 45.7% (±1.4). Soil C concentrations were 1.23% (±0.32), 0.97% (±0.10), 0.45% (±0.14), and 0.24% (±0.10) for depths of 0–25, 25–50, 50–75, and 75–100 cm. C was allocated in: (a) the trees (aboveground fraction = 118.45 Mg ha−1 and belowground fraction = 30.06 Mg ha−1), (b) the understory = 1.44 Mg ha−1, (c) the litter = 8.34 Mg ha−1, and (d) the soil (without roots) = 99.7 Mg ha−1. The share of total C stock (a + b + c + d = 258.0 Mg ha−1) was similar in the aboveground (49.7%) and belowground (50.3%) fractions, thus indicating a very high rate of C sequestration in the biomass. Eucalyptus plantations in Brazil are fast growing (for this study = 36.7 m³ ha−1 year−1) and contribute to intense carbon sequestration in above and belowground biomass (14.8 Mg ha−1 year−1).

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Management effects on the dynamics and storage rates of organic matter in long-term crop rotations

Canadian Journal of Soil Science ◽

10.4141/s03-022 ◽

2004 ◽

Vol 84 (1) ◽

pp. 49-61 ◽

Cited By ~ 16

Author(s):

E. A. Paul ◽

H. P. Collins ◽

K. Paustian ◽

E. T. Elliott ◽

S. Frey ◽

...

Keyword(s):

Organic Matter ◽

C Sequestration ◽

Organic C ◽

Soil C ◽

Site Analysis ◽

Laboratory Incubation ◽

C And N ◽

A Site ◽

Management Effects

Factors controlling soil organic matter (SOM) dynamics in soil C sequestration and N fertility were determined from multi-site analysis of long-term, crop rotation experiments in Western Canada. Analyses included bulk density, organic and inorganic C and N, particulate organic C (POM-C) and N (POM -N), and CO2-C evolved during laboratory incubation. The POM-C and POM-N contents varied with soil type. Differences in POM-C contents between treatments at a site (δPOM-C) were related (r2= 0.68) to treatment differences in soil C (δSOC). The CO2-C, evolved during laboratory incubation, was the most sensitive indicator of management effects. The Gray Luvisol (Breton, AB) cultivated plots had a fivefold difference in CO2-C release relative to a twofold difference in soil organic carbon (SOC). Soils from cropped, Black Chernozems (Melfort and Indian Head, SK) and Dark Brown Chernozems (Lethbridge, AB) released 50 to 60% as much CO2-C as grassland soils. Differences in CO2 evolution from the treatment with the lowest SOM on a site and that of other treatments (δCO2-C) in the early stages of the incubation were correlated to δPOM-C and this pool reflects short-term SOC storage. Management for soil fertility, such as N release, may differ from management for C sequestration. Key words: Multi-site analysis, soil management, soil C and N, POM-C and N, CO2 evolution

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Humus, nitrogen and energy balances, and greenhouse gas emissions in a long-term field experiment with compost compared with mineral fertilisation

Soil Research ◽

10.1071/sr15127 ◽

2016 ◽

Vol 54 (2) ◽

pp. 254 ◽

Cited By ~ 3

Author(s):

Eva Erhart ◽

Harald Schmid ◽

Wilfried Hartl ◽

Kurt-Jürgen Hülsbergen

Keyword(s):

Organic Matter ◽

Field Experiment ◽

Greenhouse Gas ◽

Ghg Emissions ◽

Organic Matter Content ◽

C Sequestration ◽

Organic C ◽

Soil C ◽

Positive Balance ◽

Energy Balances

Compost fertilisation is one way to close material cycles for organic matter and plant nutrients and to increase soil organic matter content. In this study, humus, nitrogen (N) and energy balances, and greenhouse gas (GHG) emissions were calculated for a 14-year field experiment using the model software REPRO. Humus balances showed that compost fertilisation at a rate of 8 t/ha.year resulted in a positive balance of 115 kg carbon (C)/ha.year. With 14 and 20 t/ha.year of compost, respectively, humus accumulated at rates of 558 and 1021 kg C/ha.year. With mineral fertilisation at rates of 29–62 kg N/ha.year, balances were moderately negative (–169 to –227 kg C/ha.year), and a clear humus deficit of –457 kg C/ha.year showed in the unfertilised control. Compared with measured soil organic C (SOC) data, REPRO predicted SOC contents fairly well with the exception of the treatments with high compost rates, where SOC contents were overestimated by REPRO. GHG balances calculated with soil C sequestration on the basis of humus balances, and on the basis of soil analyses, indicated negative GHG emissions with medium and high compost rates. Mineral fertilisation yielded net GHG emissions of ~2000 kg CO2-eq/ha.year. The findings underline that compost fertilisation holds potential for C sequestration and for the reduction of GHG emissions, even though this potential is bound to level off with increasing soil C saturation.

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Soil management effects on organic carbon in isolated fractions of a Gray Luvisol

Canadian Journal of Soil Science ◽

10.4141/s05-037 ◽

2006 ◽

Vol 86 (1) ◽

pp. 141-151 ◽

Cited By ~ 12

Author(s):

A. F. Plante ◽

C. E. Stewart ◽

R. T. Conant ◽

K. Paustian ◽

J. Six

Keyword(s):

Organic Matter ◽

Crop Production ◽

N Fertilization ◽

Residue Management ◽

Soil Organic C ◽

Organic C ◽

Straw Management ◽

Soil C ◽

C Pools

Agricultural management affects soil organic matter, which is important for sustainable crop production and as a greenhouse gas sink. Our objective was to determine how tillage, residue management and N fertilization affect organic C in unprotected, and physically, chemically and biochemically protected soil C pools. Samples from Breton, Alberta were fractionated and analysed for organic C content. As in previous reports, N fertilization had a positive effect, tillage had a minimal effect, and straw management had no effect on whole-soil organic C. Tillage and straw management did not alter organic C concentrations in the isolated C pools, while N fertilization increased C concentrations in all pools. Compared with a woodlot soil, the cultivated plots had lower total organic C, and the C was redistributed among isolated pools. The free light fraction and coarse particulate organic matter responded positively to C inputs, suggesting that much of the accumulated organic C occurred in an unprotected pool. The easily dispersed silt-sized fraction was the mineral-associated pool most responsive to changes in C inputs, whereas the microaggregate-derived silt-sized fraction best preserved C upon cultivation. These findings suggest that the silt-sized fraction is important for the long-term stabilization of organic matter through both physical occlusion in microaggregates and chemical protection by mineral association. Key words: Soil organic C, tillage, residue management, N fertilization, silt, clay

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Restoring nutrient circularity in a nutrient-saturated area in Germany requires systemic change

Nutrient Cycling in Agroecosystems ◽

10.1007/s10705-021-10172-3 ◽

2021 ◽

Author(s):

Bernou Zoë van der Wiel ◽

Jan Weijma ◽

Corina Everarda van Middelaar ◽

Matthias Kleinke ◽

Cees Jan Nico Buisman ◽

...

Keyword(s):

Food Waste ◽

Crop Production ◽

Agricultural Sector ◽

Agricultural Land ◽

Organic Fertilizer ◽

Animal Production ◽

N Losses ◽

Organic C ◽

Soil C ◽

Soil Accumulation

AbstractRegions with intensive agriculture often encounter environmental problems caused by nutrient excess of agro-food-waste systems that have become increasingly linear over previous decades. In this study, nitrogen (N), phosphorus (P), potassium (K) and carbon (C) flows in the whole agro-food-waste system of district Cleves in Germany were quantified simultaneously using substance flow analysis. Moreover, nutrient use inefficiency hotspots were identified to establish options to improve nutrient self-sufficiency as a first step towards nutrient circularity. Data on mass flows and nutrient contents was acquired for the year 2016 from stakeholders, statistical databases, literature and modelling. Organic C was included for flows with potential as organic fertilizer. Results show that animal production drives the nutrient flows in the export-oriented district, with feed import, manure application and losses from housing and manure storage accounting for 40, 45 and 60% of all N, P and K flows, respectively. In particular agriculture is responsible for N losses, with 150 kg N lost ha−1 agricultural land. Crop production surplus and with that soil accumulation of P and K are 515 t and 4100 t respectively. Stoichiometry of N:P:K:C in the different organic materials does not allow direct application and meeting crop requirements without exceeding demand of especially P. Processing of biomass is therefore required. Based on mass, especially manure holds potential for processing into bio-based fertilizers. To improve nutrient cycling and soil C conservation, being an important element for a sustainable agricultural sector, local balances between crop and animal production need to be considered.

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