Management of Soil Organic Carbon for Soil Health in Agroecosystems

A special issue of Agronomy (ISSN 2073-4395). This special issue belongs to the section "Soil and Plant Nutrition".

Deadline for manuscript submissions: closed (4 April 2021) | Viewed by 41449

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Guest Editor
Department of Agricultural and Food Sciences, University of Bologna, Bologna, Italy
Interests: anaerobic digestion; biomass recycling and use; soil organic matter; FTIR; Raman; NMR; CF-IRMS; TG-DTA; biostimulants’ biological activity; white-rot fungi
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Special Issue Information

Dear Colleagues,

Soil organic carbon (SOC) is a key component of soil health in agroecosystems. Improving SOC reserves increases soil fertility and thus largely leads to soil ability to sustain biodiversity, soil structure maintenance, regulation of pests and disease, and ensure food security. Moreover, it has been widely accepted that SOC may have great potential for climate change mitigation on a global scale, as well as the dynamics of soil carbon storage and actions to promote it.

The management of SOC implies relevant strategies including different farming systems, conservation agriculture, integrated agriculture, and the application of organic fertilizers that are necessary to achieve a positive C balance and provide better nutrient control for the recovery of soil functions. Therefore, it is only through sustainable agricultural practices and their effects on SOC dynamics that soil health is safeguarded.

I cordially invite authors to contribute to this Special Issue with novel research and reviews that will give the readers of Agronomy updated and new perspectives about the influence of agronomical practices and approaches (conventional, organic, agroecological, or precision agriculture) on soil health, and effects on soil properties, plant nutrition, biodiversity of rhizospheric soil, food security and changing climate change scenarios.

Prof. Ornella Francioso
Guest Editor

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Keywords

  • Soil organic carbon
  • Soil health
  • Soil carbon sequestration
  • Climate change
  • Sustainable agricultural practices
  • Agroecology

Published Papers (11 papers)

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Research

Jump to: Review

14 pages, 2156 KiB  
Article
Assessment of the Short-Term Impact of Anaerobic Digestate on Soil C Stock and CO2 Emissions in Shallow Water Table Conditions
by Ilaria Piccoli, Ornella Francioso, Carlo Camarotto, Gemini Delle Vedove, Barbara Lazzaro, Paolo Giandon and Francesco Morari
Agronomy 2022, 12(2), 504; https://doi.org/10.3390/agronomy12020504 - 17 Feb 2022
Cited by 4 | Viewed by 1587
Abstract
Anaerobic digestion has been recently proposed as a more sustainable energy supply chain able to strengthen the existing security of supply provisions. Anaerobic digestate (AD) is the by-product of the anaerobic digestion process and presents organic fertilizer characteristics, but its agronomic usage has [...] Read more.
Anaerobic digestion has been recently proposed as a more sustainable energy supply chain able to strengthen the existing security of supply provisions. Anaerobic digestate (AD) is the by-product of the anaerobic digestion process and presents organic fertilizer characteristics, but its agronomic usage has been hindered by both agronomic and environmental concerns. In this study, the impact of agricultural liquid (LD) and solid (SD) AD and beef manure (Man) was evaluated on some agro-environmental characteristics. First, the AD fractions functional groups were characterized by FT-IR, and then LD and SD performances were evaluated on soil organic carbon (SOC) stock and carbon dioxide (CO2) emissions and compared to beef manure (Man). The fertilizer impact was also considered with the presence or absence of a shallow water table. Results showed that SD increased of ca. 3 t ha−1 the SOC stock in the 0–20 cm soil profile with respect to LD, while it was comparable to Man despite the lower C input (6.7 vs. 8.7 t C ha−1), due to the presence of more stable compounds (e.g., lignin). The CO2 fluxes were affected by both fertilizer type and water table level. In the absence of a water table, the CO2 emissions (5.5 g CO2 m2 d−1) were driven by carbon content and quality in the fertilizer, while the presence of a shallower water table hindered mineralization of stable SOC and, in turn, reduced emissions (4.4 g CO2 m2 d−1). AD can be considered a beneficial solution to both maintain soil fertility and, at the same time, give new insight into a circular economy model, although further investigation on GHG emissions is required. Full article
(This article belongs to the Special Issue Management of Soil Organic Carbon for Soil Health in Agroecosystems)
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24 pages, 7758 KiB  
Article
The C4 Atriplex halimus vs. the C3 Atriplex hortensis: Similarities and Differences in the Salinity Stress Response
by Roberta Calone, Antonio Cellini, Luigi Manfrini, Carla Lambertini, Paola Gioacchini, Andrea Simoni and Lorenzo Barbanti
Agronomy 2021, 11(10), 1967; https://doi.org/10.3390/agronomy11101967 - 29 Sep 2021
Cited by 5 | Viewed by 2208
Abstract
Soil properties and the ability to sustain agricultural production are seriously impaired by salinity. The cultivation of halophytes is seen as a solution to cope with the problem. In this framework, a greenhouse pot experiment was set up to assess salinity response in [...] Read more.
Soil properties and the ability to sustain agricultural production are seriously impaired by salinity. The cultivation of halophytes is seen as a solution to cope with the problem. In this framework, a greenhouse pot experiment was set up to assess salinity response in the perennial C4 species Atriplex halimus, and in the following three cultivars of the annual C3 Atriplex hortensis: green, red, and scarlet. The four genotypes were grown for 35 days with water salinity (WS) ranging from 0 to 360 mM NaCl. Plant height and fresh weight (FW) increased at 360 vs. 0 WS. The stomatal conductance (GS) and transpiration rate (E) were more severely affected by salinity in the C4 A. halimus than in the C3 species A. hortensis. This was reflected in a lower leaf water potential indicating stronger osmotic adjustment, and a higher relative water content associated with more turgid leaves, in A. halimus than A. hortensis. In a PCA including all the studied traits, the GS and E negatively correlated to the FW, which, in turn, positively correlated with Na concentration and intrinsic water use efficiency (iWUE), indicating that reduced gas exchange associated with Na accumulation contributed to sustain iWUE under salinity. Finally, FTIR spectroscopy showed a reduced amount of pectin, lignin, and cellulose under salinity, indicating a weakened cell wall structure. Overall, both species were remarkably adapted to salinity: From an agronomic perspective, the opposite strategies of longer vs. faster soil coverage, involved by the perennial A. halimus vs. the annual A. hortensis cv. scarlet, are viable natural remedies for revegetating marginal saline soils and increasing soil organic carbon. Full article
(This article belongs to the Special Issue Management of Soil Organic Carbon for Soil Health in Agroecosystems)
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15 pages, 2026 KiB  
Article
Soil Response to Agricultural Land Abandonment: A Case Study of a Vineyard in Northern Italy
by Luigi Sciubba, Martina Mazzon, Luciano Cavani, Elena Baldi, Moreno Toselli, Claudio Ciavatta and Claudio Marzadori
Agronomy 2021, 11(9), 1841; https://doi.org/10.3390/agronomy11091841 - 14 Sep 2021
Cited by 9 | Viewed by 1936
Abstract
Agricultural land abandonment is an emerging problem in European Union (EU), and about 11% of agricultural EU land is at high risk of abandonment in the coming 10 years. Land abandonment may have both positive and negative effects in ecosystems. Due to the [...] Read more.
Agricultural land abandonment is an emerging problem in European Union (EU), and about 11% of agricultural EU land is at high risk of abandonment in the coming 10 years. Land abandonment may have both positive and negative effects in ecosystems. Due to the potential for land abandonment to increase soil fertility, the study of vegetation succession effects on soil quality is of great importance. In this study, we investigated an abandoned vineyard where, after a period of 30 years, rows and alleys were characterized by two different forms of vegetation succession: natural recolonization by trees along the rows and by herbaceous vegetation in the alleys. No-tilled alleys covered by herbaceous vegetation of a neighboring conventionally cultivated vineyard were used as a comparison. Soil samples were chemically characterized (pH, extractable element, and available and total metals), and analyzed for the determination of carbon (C) and nitrogen (N) pools; hydrolytic and phenol oxidizing (PO) enzyme activities involved in C, N, and phosphorus (P) cycles; and the enzyme ratios. Results highlighted that natural recolonization by trees increased the organic C and N soil pools by 58% and 34%, respectively, compared to the natural recolonization by herbaceous vegetation. Moreover, natural recolonization by trees reduced β-glucosidase by 79%, urease by 100%, alkaline phosphastase by 98%, acid phosphatase specific hydrolytic activities by 50%, and catechol oxidase and laccase specific oxidative activities by 127% and 119%, respectively, compared to the renaturalization by herbaceous vegetation. In addition, the natural recolonization by trees reduced the C (βglu):C (PO) enzymes ratio by 16% compared to that of the conventional vineyard. Comparing the natural recolonization by herbaceous vegetation with that of the conventional vineyard revealed little significant difference (15% of the measured and calculated parameters); in particular, PO activities significantly decreased in the renaturalized vineyard with herbaceous vegetation by 49% (catechol oxidase) and 52% (laccase), and the C (βglu):C (PO) enzyme ratio showed a reduction (−11%) in the vineyard naturally recolonized by herbaceous vegetation compared to the conventional vineyard. This highlights that the type of vegetation succession that takes place after land abandonment may have a significant impact in terms of soil fertility and C accrual potential. These results help to focus attention on the practices used in agro-forestry that should be adopted in abandoned agro-ecosystems to increase their biodiversity, soil C stock, and soil quality, because these indicators are affected by the type of vegetative coverage. Full article
(This article belongs to the Special Issue Management of Soil Organic Carbon for Soil Health in Agroecosystems)
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17 pages, 28379 KiB  
Article
Soil Quality and Organic Matter Pools in a Temperate Climate (Northern Italy) under Different Land Uses
by Livia Vittori Antisari, William Trenti, Mauro De Feudis, Gianluca Bianchini and Gloria Falsone
Agronomy 2021, 11(9), 1815; https://doi.org/10.3390/agronomy11091815 - 9 Sep 2021
Cited by 10 | Viewed by 2137
Abstract
Temperate soils are threatened by degradation and soil organic matter (SOM) loss due to a combination of geomorphology, soil types, and anthropic pressure. In 54 sites in Northern Italy, characterized by different land uses, climates, geological substrates, and soils, we assessed (i) the [...] Read more.
Temperate soils are threatened by degradation and soil organic matter (SOM) loss due to a combination of geomorphology, soil types, and anthropic pressure. In 54 sites in Northern Italy, characterized by different land uses, climates, geological substrates, and soils, we assessed (i) the soil quality, (ii) the SOM accumulation/degradation patterns, and (iii) whether land use and related soil management practices are sustainable based on changes in soil quality. Soil samples from the 0–15 and 15–30 cm deep layers were collected and analyzed for the soil parameters recommended by the FAO (bulk density, pH, organic and microbial C, total N, and soil respiration rate) and for the chemical SOM pools. Parameters related to the efficient use of soil microbial C were also calculated. The findings showed that agricultural lands where organic material was added had good soil quality and used microbial C efficiently. Reclaimed peaty soils degraded because the conditions were too stressful for the soil microbial biomass as supported by high metabolic quotient and the low values of mineralization quotient, microbial quotient, and soil biofertility index. Conservative management practices carried out in chestnuts were found to have a decreased soil degradation risk. An investigation of the soil parameters recommended by the FAO can be used to evaluate sustainable practices and soil quality on microbial activity and SOM dynamics. Full article
(This article belongs to the Special Issue Management of Soil Organic Carbon for Soil Health in Agroecosystems)
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21 pages, 521 KiB  
Article
Influence of Tillage and Crop Rotations in Organic and Conventional Farming Systems on Soil Organic Matter, Bulk Density and Enzymatic Activities in a Short-Term Field Experiment
by Marco Pittarello, Nicola Dal Ferro, Francesca Chiarini, Francesco Morari and Paolo Carletti
Agronomy 2021, 11(4), 724; https://doi.org/10.3390/agronomy11040724 - 9 Apr 2021
Cited by 11 | Viewed by 2807
Abstract
Intensive agricultural practices are leading to loss of soil fertility and overexploitation of natural resources which cause nutrients imbalance and further impair ecosystem services. Organic farming (OF), also coupled with minimum tillage and crop rotations, represents one of the strategies to limit this [...] Read more.
Intensive agricultural practices are leading to loss of soil fertility and overexploitation of natural resources which cause nutrients imbalance and further impair ecosystem services. Organic farming (OF), also coupled with minimum tillage and crop rotations, represents one of the strategies to limit this process and maintain soil functions. In a two-year field trial, organic farming practices, including a set of fertilizations combined with crop rotations and association with nitrogen fixing cover crops, were compared. The aim of this research was to assess in the short-term the effects on soil organic carbon, aggregate stability, and soil enzymes activities of using a combination of promising management practices in the delta region of the Po river. Results did not show improvements in organic carbon content and soil aggregate stability. Conversely, enzymatic activities were always significantly higher in OF treatments than the conventional one. Crop rotation and associated legumes were effective in enhancing β-glucosidase and P fixation through phosphatases activities. The present work suggests that an effective choice of crop species coupled with legumes can enhance biological activity re-starting main mechanisms of microbial development even without a contemporary increase of organic matter. Full article
(This article belongs to the Special Issue Management of Soil Organic Carbon for Soil Health in Agroecosystems)
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15 pages, 664 KiB  
Article
Wood-Based Compost Affects Soil Fertility and the Content of Available Forms of Nutrients in Vineyard and Field-Scale Agroecosystems
by Diego Pizzeghello, Livio Bellin, Serenella Nardi, Ornella Francioso, Andrea Squartini and Giuseppe Concheri
Agronomy 2021, 11(3), 518; https://doi.org/10.3390/agronomy11030518 - 10 Mar 2021
Cited by 5 | Viewed by 3035
Abstract
To counteract the loss of organic matter of agricultural soils, the use of compost from green and woody residues is a promising strategy. In this study, an organic farm (NE Italy) was investigated to determine the effect of management practices on physical and [...] Read more.
To counteract the loss of organic matter of agricultural soils, the use of compost from green and woody residues is a promising strategy. In this study, an organic farm (NE Italy) was investigated to determine the effect of management practices on physical and chemical soil properties. The organic system received three years ago a single high dose (60 t ha−1) of a wood-based compost (WBC), and it was compared with a conventional farm that annually managed mineral plus manure fertilization. In both systems, soil samples from a vineyard and field-scale rotation were collected, together with soil samples from an area not cultivated and not treated neither with compost nor with fertilizers or manure (untreated = control). Soil samples were characterized for soil fertility parameters, extractable fractions of macro- and micronutrients with DTPA and Mehlich3, and their total content. WBC was physically, chemically, and biologically characterized. The results showed that WBC fulfilled the requirements prescribed by Italian legislation, and the absence of phytotoxicity and conversely a stimulating activity towards root development was evidenced. From the DNA metabarcoding of the bacterial community, WBC revealed several peculiarities, including the dominance of taxa such as the order Acidimicrobiales, the families Anerolineaceae, Cytophagaceae, Caldimicrobiacese, Saprospiraceae and the archaeon Candidatus Nitrososphaera. Concerning the fertility of soils, the addition of WBC in both the vineyard and field-scale considerably affected some important soil parameters compared to those of conventional fertilization and untreated soil. Among these, WBC strongly increased the organic C content and the amount of the available P. In addition, the concentrations of macro- and micronutrients extractable by DTPA were generally higher with WBC than conventional fertilization. On the contrary, Mehlich3 extractable metals and total metals content were not affected by fertilization. The principal component analysis indicated that organic C, macronutrients (CaDTPA, KDTPA, and POlsen), as well as micronutrients (BDTPA, FeDTPA, and MoDTPA) are principal factors that properly separated conventional fertilization from organic fertilization. Beside this, within the same management, cases by agroecosystem were also well revealed by cluster analysis. In essence, in the short-term, the organic system led to a significant improvement in organic C and plant-available nutrients over the conventional system. Full article
(This article belongs to the Special Issue Management of Soil Organic Carbon for Soil Health in Agroecosystems)
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38 pages, 1303 KiB  
Article
Soil Organic Carbon Dynamics in Semi-Arid Irrigated Cropping Systems
by Andrew M. Bierer, April B. Leytem, Robert S. Dungan, Amber D. Moore and David L. Bjorneberg
Agronomy 2021, 11(3), 484; https://doi.org/10.3390/agronomy11030484 - 5 Mar 2021
Cited by 9 | Viewed by 3649
Abstract
Insufficient characterization of soil organic carbon (SOC) dynamics in semi-arid climates contributes uncertainty to SOC sequestration estimates. This study estimated changes in SOC (0–30 cm depth) due to variations in manure management, tillage regime, winter cover crop, and crop rotation in southern Idaho [...] Read more.
Insufficient characterization of soil organic carbon (SOC) dynamics in semi-arid climates contributes uncertainty to SOC sequestration estimates. This study estimated changes in SOC (0–30 cm depth) due to variations in manure management, tillage regime, winter cover crop, and crop rotation in southern Idaho (USA). Empirical data were used to drive the Denitrification Decomposition (DNDC) model in a “default” and calibrated capacity and forecast SOC levels until 2050. Empirical data indicates: (i) no effect (p = 0.51) of winter triticale on SOC after 3 years; (ii) SOC accumulation (0.6 ± 0.5 Mg ha–1 year–1) under a rotation of corn-barley-alfalfax3 and no change (p = 0.905) in a rotation of wheat-potato-barley-sugarbeet; (iii) manure applied annually at rate 1X is not significantly different (p = 0.75) from biennial application at rate 2X; and (iv) no significant effect of manure application timing (p = 0.41, fall vs. spring). The DNDC model simulated empirical SOC and biomass C measurements adequately in a default capacity, yet specific issues were encountered. By 2050, model forecasting suggested: (i) triticale cover resulted in SOC accrual (0.05–0.27 Mg ha–1 year–1); (ii) when manure is applied, conventional tillage regimes are favored; and (iii) manure applied treatments accrue SOC suggesting a quadratic relationship (all R2 > 0.85 and all p < 0.0001), yet saturation behavior was not realized when extending the simulation to 2100. It is possible that under very large C inputs that C sequestration is favored by DNDC which may influence “NetZero” C initiatives. Full article
(This article belongs to the Special Issue Management of Soil Organic Carbon for Soil Health in Agroecosystems)
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15 pages, 2498 KiB  
Article
Arable Podzols Are a Substantial Carbon Sink under Current and Future Climates: Evidence from a Long-Term Experiment in the Vladimir Region, Russia
by Igor Ilichev, Vladimir Romanenkov, Sergei Lukin, Vera Pavlova, Stanislav Siptits and Pavel Krasilnikov
Agronomy 2021, 11(1), 90; https://doi.org/10.3390/agronomy11010090 - 6 Jan 2021
Cited by 2 | Viewed by 1979
Abstract
Soil organic carbon (SOC) is an essential component of soil health and a potential sink for greenhouse gases. SOC dynamics in a long-term field experiment with mineral and organic fertilization on loamy sand podzol in the Vladimir Region, Russia, was traced with the [...] Read more.
Soil organic carbon (SOC) is an essential component of soil health and a potential sink for greenhouse gases. SOC dynamics in a long-term field experiment with mineral and organic fertilization on loamy sand podzol in the Vladimir Region, Russia, was traced with the dynamic carbon model RothC from 1968 until the present. During this period, C stock increased by 21%, compared to the initial level, with the application of manure, at an average annual rate of 10 t·ha−1. The model was also used to forecast SOC changes up to 2090 for two contrasting RCP4.5 and RCP8.5 climatic scenarios. Up to 2090, steady growth of SOC stocks is expected in all compared treatments for both climate scenarios. In the scenarios, this growth rate was the highest up to 2040, decreased in the period 2040–2070, and increased again in the period 2070–2090 for RCP4.5. The highest annual gain was 21–27‰ under the RCP4.5 scenario and 16–21‰ under the RCP8.5 scenario in 2020–2040 in a 0–20 cm soil layer. Under the expected climate conditions in the 21st century, the C input will increase 1.3–1.5 times under the RCP4.5 scenario and decrease by 13–20% for the same period under the RCP 8.5 scenario. Modelling demonstrated potentially more favourable conditions for SOC stability in arable podzols than in Retisols in central Russia in the 21st century. Full article
(This article belongs to the Special Issue Management of Soil Organic Carbon for Soil Health in Agroecosystems)
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18 pages, 14618 KiB  
Article
Kinetics of C Mineralization of Biochars in Three Excessive Compost-Fertilized Soils: Effects of Feedstocks and Soil Properties
by Chen-Chi Tsai and Yu-Fang Chang
Agronomy 2020, 10(11), 1749; https://doi.org/10.3390/agronomy10111749 - 10 Nov 2020
Cited by 8 | Viewed by 1998
Abstract
The aim of this work was to compare the carbon (C) mineralization kinetics of three biochars (Formosan ash (Fraxinus formosana Hayata), ash biochar; Makino bamboo (Phyllostachys makino Hayata), bamboo biochar; and lead tree (Leucaena leucocephala (Lam.) de. Wit), lead tree [...] Read more.
The aim of this work was to compare the carbon (C) mineralization kinetics of three biochars (Formosan ash (Fraxinus formosana Hayata), ash biochar; Makino bamboo (Phyllostachys makino Hayata), bamboo biochar; and lead tree (Leucaena leucocephala (Lam.) de. Wit), lead tree biochar) applied with two addition rates (2 and 5 wt %) in three excessive compost-fertilized (5 wt %) soils (one Oxisols and two Inceptisols), and to ascertain the increasing or decreasing effect of biochar and soil type in the presence of excessive compost. The study results of 400 days incubation indicated that, in general, the potential of the three biochars for C sequestration is similar in the three studied soils. The presence of excessive compost stimulated the co-mineralization of the more labile components of biochar over the short term (first two months). The potential of biochar addition for neutralizing soil pH and regulating the release of Al from soil for preserving soil organic carbon (SOC) might be the important mechanisms in biochar-compost interactions, especially in the presence of excessive compost. Overall, 5% application rate of three high temperature-pyrolysis biochars showed the less detriments to studied soils. In these incubations of biochar, excessive compost, and soil, it is a decreasing effect overall, that is, the enhanced storage of both biochar-C and SOC, which is expected as a long-term carbon sequestration in soil. The recorded direction and magnitude of effect, both are strongly influenced by biochar and soil type. When co-applied with excessive compost, the negative (reducing CO2 release) effect with increasing biochar application rates was eliminated. Full article
(This article belongs to the Special Issue Management of Soil Organic Carbon for Soil Health in Agroecosystems)
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Review

Jump to: Research

28 pages, 664 KiB  
Review
Optimizing Carbon Sequestration in Croplands: A Synthesis
by Alexandra Tiefenbacher, Taru Sandén, Hans-Peter Haslmayr, Julia Miloczki, Walter Wenzel and Heide Spiegel
Agronomy 2021, 11(5), 882; https://doi.org/10.3390/agronomy11050882 - 29 Apr 2021
Cited by 63 | Viewed by 10597
Abstract
Climate change and ensuring food security for an exponentially growing global human population are the greatest challenges for future agriculture. Improved soil management practices are crucial to tackle these problems by enhancing agro-ecosystem productivity, soil fertility, and carbon sequestration. To meet Paris climate [...] Read more.
Climate change and ensuring food security for an exponentially growing global human population are the greatest challenges for future agriculture. Improved soil management practices are crucial to tackle these problems by enhancing agro-ecosystem productivity, soil fertility, and carbon sequestration. To meet Paris climate treaty pledges, soil management must address validated approaches for carbon sequestration and stabilization. The present synthesis assesses a range of current and potential future agricultural management practices (AMP) that have an effect on soil organic carbon (SOC) storage and sequestration. Through two strategies—increasing carbon inputs (e.g., enhanced primary production, organic fertilizers) and reducing SOC losses (e.g., reducing soil erosion, managing soil respiration)—AMP can either sequester, up to 714 ± 404 (compost) kg C ha−1 y−1, having no distinct impact (mineral fertilization), or even reduce SOC stocks in the topsoil (bare fallow). Overall, the carbon sequestration potential of the subsoil (>40 cm) requires further investigation. Moreover, climate change, permanent soil sealing, consumer behavior in dietary habits and waste production, as well as the socio-economic constraints of farmers (e.g., information exchange, long-term economic profitability) are important factors for implementing new AMPs. This calls for life-cycle assessments of those practices. Full article
(This article belongs to the Special Issue Management of Soil Organic Carbon for Soil Health in Agroecosystems)
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41 pages, 12128 KiB  
Review
Recent Developments in Understanding Biochar’s Physical–Chemistry
by Pellegrino Conte, Roberta Bertani, Paolo Sgarbossa, Paola Bambina, Hans-Peter Schmidt, Roberto Raga, Giuseppe Lo Papa, Delia Francesca Chillura Martino and Paolo Lo Meo
Agronomy 2021, 11(4), 615; https://doi.org/10.3390/agronomy11040615 - 24 Mar 2021
Cited by 37 | Viewed by 8038
Abstract
Biochar is a porous material obtained by biomass thermal degradation in oxygen-starved conditions. It is nowadays applied in many fields. For instance, it is used to synthesize new materials for environmental remediation, catalysis, animal feeding, adsorbent for smells, etc. In the last decades, [...] Read more.
Biochar is a porous material obtained by biomass thermal degradation in oxygen-starved conditions. It is nowadays applied in many fields. For instance, it is used to synthesize new materials for environmental remediation, catalysis, animal feeding, adsorbent for smells, etc. In the last decades, biochar has been applied also to soils due to its beneficial effects on soil structure, pH, soil organic carbon content, and stability, and, therefore, soil fertility. In addition, this carbonaceous material shows high chemical stability. Once applied to soil it maintains its nature for centuries. Consequently, it can be considered a sink to store atmospheric carbon dioxide in soils, thereby mitigating the effects of global climatic changes. The literature contains plenty of papers dealing with biochar’s environmental effects. However, a discrepancy exists between studies dealing with biochar applications and those dealing with the physical-chemistry behind biochar behavior. On the one hand, the impression is that most of the papers where biochar is tested in soils are based on trial-and-error procedures. Sometimes these give positive results, sometimes not. Consequently, it appears that the scientific world is divided into two factions: either supporters or detractors. On the other hand, studies dealing with biochar’s physical-chemistry do not appear helpful in settling the factions’ problem. This review paper aims at collecting all the information on physical-chemistry of biochar and to use it to explain biochar’s role in different fields of application. Full article
(This article belongs to the Special Issue Management of Soil Organic Carbon for Soil Health in Agroecosystems)
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