scholarly journals Role of Seasonality and Fire in Regulating the Enzymatic Activities in Soils Covered by Different Vegetation in a Mediterranean Area

2021 ◽  
Vol 11 (18) ◽  
pp. 8342
Author(s):  
Valeria Memoli ◽  
Lucia Santorufo ◽  
Giorgia Santini ◽  
Paola Musella ◽  
Rossella Barile ◽  
...  
Keyword(s):  
Organic Matter ◽  
Black Locust ◽  
Mediterranean Area ◽  
Fire Frequency ◽  
Climatic Conditions ◽  
Enzymatic Activities ◽  
Holm Oak ◽  
C And N ◽  
Burnt Areas

As they quickly respond to environmental conditions, soil enzymes, involved in nutrient cycles, are considered good indicators of soil quality. The Mediterranean area is a peculiar environment for climatic conditions and for fire frequency. Therefore, the research aimed to evaluate the role of seasonality and fire on enzymatic activities (i.e., hydrolase, dehydrogenase, and β-glucosidase) in soils covered by herbs, black locust, pine, and holm oak. In addition, the main soil abiotic properties that drive the enzymatic activities were also investigated. In order to achieve the aims, surface soils were collected in unburnt and burnt areas and characterized for water and organic matter contents, pH, concentrations of C and N, and available fractions of Al, Ca, Cu, Fe, Mg, Mn, Na, and Pb. The results highlighted that the soil enzymatic activities were mainly affected by seasonality more than by fire; in unburnt soils, their main drivers were nutrient availabilities, whereas, in burnt soils they were pH, water and organic matter contents, C and N concentrations, and both nutrient and metal availabilities. Finally, holm oak, as compared with herbs, pine, and black locust, conferred higher stability to soils that were affected by seasonality and fire.

C and N stocks and the role of molecular recalcitrance and organomineral interaction in stabilizing soil organic matter in a subtropical Acrisol managed under no-tillage

Geoderma ◽  
2006 ◽  
Vol 133 (3-4) ◽  
pp. 258-268 ◽  
Author(s):  
Cimélio Bayer ◽  
Ladislau Martin-Neto ◽  
João Mielniczuk ◽  
Jeferson Dieckow ◽  
Telmo J.C. Amado
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
No Tillage ◽  
C And N

Arbuscular Mycorrhizal symbiosis enhances aggregate formation and organic matter sequestration in alkaline Fe ore tailings

2021 ◽  
Author(s):  
Zhen Li ◽  
Songlin Wu ◽  
Longbin Huang
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Aggregate Formation ◽  
Organic C ◽  
Mineral Particles ◽  
Am Symbiosis ◽  
C And N

<p>Alkaline Fe ore tailings are by far one of the most challenging environmental issue facing the global mining industry, which is ranked 4<sup>th</sup> globally in terms of their discharge volumes in storage dams. These tailings possess poor physical structures and adverse chemical properties (e.g., alkaline pH and deficiencies of organic carbon and nutrients) and it is hard for sustainable colonization of plants and microbial communities. Eco-engineering tailings into soil-like substrate in situ is a promising technology to achieve sustainable rehabilitation of tailing landscape. The formation of water stable aggregates (WSA) in tailings primed with eco-engineering inpiuts (e.g., plant biomass organic matter and fertilisers) is indicative of the first milestone of soil formaiton, resulting from bio-geochemically driven mineral weathering and cementation. WSAs are basic physical units underpinning soil structure and functions, such as the porosity and hydraulic conductivity, gas exchange and water retention, biological activities of microbes and roots. The further development and evolution may be enhanced by Arbuscular mycorrhizal (AM) fungi associated with plants colonising infertile soil (such as tailing-soil), because of their role in generating organic cements and organo-mineral interactions. Our previous study found that AM fungi were present in the Fe ore mine tailing site, associated with colonising native plants. In the present study, we have investigated the role of AM symbiosis (Glomus spp. in association with Sorghum spp.) in aggregate formation and organic matter sequestration in Fe ore tailings eco-engineered with organic matter amendment and pioneer plant colonization. The results showed that AM fungi formed symbiotic association with Sorghum spp. plant roots (with mycorrhizal colonization intensity above 80%) in the eco-engineered tailings. Quantitatively, AM symbiosis enhanced the formation of micro-aggregates (53~250 um) rather than macro-aggregate aggregates (250 um~2000 um) formation, which may be partially due to the direct role of extra-radical mycelium as revealed by FE-SEM analysis. Qualitatively, AM symbiosis increased the amount of organic carbon and nitrogen associated with mineral particles in the macro-aggregates. Those organic carbon associated with minerals was found to be rich in carboxyl C and alkyl C, as revealed by synchrotron based C 1s X-ray absorption near edge structure (NEXAFS, conducted in Australia Synchrotron) and the Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectra. Overall, the study revealed the role of AM fungi in advancing the formation of microaggregates and increasing the sequestration of organic C and N in macroaggregates in the eco-engineered Fe ore tailings. These suggest that AM fungi inoculum be added to pioneer plants to not only enhance plant growth via improved nutrient and water acquisition, but also to advance aggregate formation and quality via increased organic C and N sequestration with impacted mineral particles.</p>

Soil organic amendments for restoring degraded drylands: strategies, recommendations and challenges for large-scale application

2020 ◽  
Author(s):  
Paloma Hueso-Gonzalez ◽  
Miriam Muñoz-Rojas
Keyword(s):  
Organic Matter ◽  
Large Scale ◽  
Organic Amendments ◽  
Renewable Resource ◽  
Biological Properties ◽  
Climatic Conditions ◽  
Soil Restoration ◽  
Application Rates

<p>Soil is an essential and non-renewable resource in natural and agricultural ecosystems with extremely slow formation and regeneration potential. In dryland areas, many ecosystems are being seriously affected by degradation processes because of an excessive use of agro-chemicals, deep tillage and intensive irrigation, among many other factors. The decline in soil organic matter is also becoming a major cause of soil degradation, particularly in dryland regions where low soil fertility cannot always maintain a sustainable production. The use of organic amendments in ecosystem restoration programs can be an effective technique for promoting soil restoration processes in degraded drylands and several studies have shown their benefits for improving soil physical, chemical and biological properties. This recovery is a result of the rapid increment of organic matter and clay contents in the soil in the short term. In the long-term, soil structure becomes more stable and water holding capacity, permeability and infiltration are improved, whereas surface runoff and erosion are reduced. Nevertheless, there are many research gaps in the knowledge of the effects of climatic conditions on their application, as well as the adequate types of amendment and doses and decomposition rates. In this presentation, we evaluate the role of organic amendments as an effective strategy in dryland restoration, highlighting the effects of different amendment types, doses and application rates. We will specifically address: (1) type of amendments and benefits arising from their use, (2) application methods and more appropriate doses and, (3) potential risk derivates for their application. We also showcase some recent case studies using organic amendments in degraded dryland areas from Spain and Australia.</p>

scholarly journals Soil carbon and nitrogen erosion in forested catchments: implications for erosion-induced terrestrial carbon sequestration

2015 ◽  
Vol 12 (3) ◽  
pp. 2491-2532 ◽  
Author(s):  
E. Stacy ◽  
S. C. Hart ◽  
C. T. Hunsaker ◽  
D. W. Johnson ◽  
A. A. Berhe
Keyword(s):  
Organic Matter ◽  
Soil Erosion ◽  
Sierra Nevada ◽  
Climatic Conditions ◽  
Stream Channels ◽  
Forested Catchments ◽  
Stream Flows ◽  
Terrestrial Carbon Sequestration ◽  
C And N ◽  
Low Order

Abstract. Soil erosion plays important roles in organic matter (OM) storage and persistence in dynamic landscapes. The biogeochemical implication of soil erosion has been a focus of a growing number of studies over the last two decades. However, most of the available studies are conducted in agricultural systems or grasslands, and hence very little information is available on rate and nature of soil organic matter (SOM) eroded from forested upland ecosystems. In the southern parts of the Sierra Nevada Mountains in California, we determined the rate of carbon (C) and nitrogen (N) eroded from two sets of catchments under different climatic conditions to determine how the amount and distribution of precipitation affects lateral distribution of topsoil and associated SOM. We quantified sediment and SOM exported annually (for water years 2005–2011) from four low-order, snow-dominated catchments, and four low-order catchments that receive a mix of rain, and snow and compared it to soil at three different landform positions from the source slopes to determine if there is selective transport of some soil OM components. We found that the amount of sediment exported varied from 0.4 to 177 kg N ha-1, while export of particulate C was between 0.025 and 4.2 kg C ha-1, compared to export of particulate N that was between 0.001 and 0.04 kg ha-1. Sediment yield and composition showed high interannual variation, with higher C and N concentrations in sediment collected in drier years. In our study catchments, erosion laterally mobilized OM-rich topsoil and litter material, some of which readily enters streams owing to the topography in these catchments that includes steep slopes adjacent to stream channels. Annual lateral sediment mass, C, and N fluxes were positively and strongly correlated with stream flows. Our results suggest that variability in climate, represented by stream discharge, is a primary factor controlling the magnitude of C and N eroded from upland temperature forest catchments.

Characterisation of production of organic rich topsoil from sludge

2000 ◽  
Vol 42 (9) ◽  
pp. 195-201 ◽  
Author(s):  
P. Andreasen ◽  
P. B. Mortensen ◽  
A. Stubsgaard ◽  
B. Langdahl
Keyword(s):  
Organic Matter ◽  
Oxygen Consumption ◽  
Oxygen Transport ◽  
Mineral Soil ◽  
Climatic Conditions ◽  
Growth Media ◽  
Soil Mixture ◽  
Water Suspension ◽  
Aerobic Process ◽  
Stable Product

The stabilisation of a sludge-mineral soil mixture and a method to evaluate the state of stabilisation were investigated. The organic matter and nitrogen content are reduced up to 50% during a stabilisation process of three months under Danish climatic conditions. The stabilisation was shown to be an aerobic process limited by oxygen transport within the mixture. The degree of stabilisation was evaluated by oxygen consumption in a water suspension and the results showed that a stable product was achieved when oxygen consumption was stable and in the level of natural occurring aerobic soils (0.1 mgO2/(g DS*hr). The study thereby demonstrates that a stability of a growth media can be controlled by the oxygen consumption method tested.

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