Fungi contribute more than bacteria to soil organic matter through necromass accumulation under different agricultural practices during the early pedogenesis of a Mollisol

2015 ◽  
Vol 67 ◽  
pp. 51-58 ◽  
Author(s):  
Na Li ◽  
Yu-Zhi Xu ◽  
Xiao-Zeng Han ◽  
Hong-Bo He ◽  
Xu-dong Zhang ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Agricultural Practices

scholarly journals Glomalin – an interesting protein part of the soil organic matter

2020 ◽  
Vol 15 (No. 2) ◽  
pp. 67-74 ◽  
Author(s):  
Vítězslav Vlček ◽  
Miroslav Pohanka
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Arbuscular Mycorrhiza ◽  
Mycorrhizal Fungi ◽  
Biological Diversity ◽  
Agricultural Practices ◽  
Arbuscular Mycorrhizal ◽  
Fulvic Acids ◽  
Soil Parameters ◽  
Citrate Buffer

The negative effects of the current agricultural practices include erosion, acidification, loss of soil organic matter (dehumification), loss of soil structure, soil contamination by risky elements, reduction of biological diversity and land use for non-agricultural purposes. All these effects are a huge risk to the further development of soil quality from an agronomic point of view and its resilience to projected climate change. Organic matter has a crucial role in it. Relatively significant correlations with the quality or the health of soil parameters and the soil organic matter or some fraction of the soil organic matter have been found. In particular, Ctot, Cox, humic and fulvic acids, the C/N ratio, and glomalin. Our work was focused on glomalin, a glycoprotein produced by the hyphae and spores of arbuscular mycorrhizal fungi (AMF), which we classify as Glomeromycota. Arbuscular mycorrhiza, and its molecular pathways, is not a well understood phenomenon. It appears that many proteins are involved in the arbuscular mycorrhiza from which glomalin is probably one of the most significant. This protein is also responsible for the unique chemical and physical properties of soils and has an ecological and economical relevance in this sense and it is a real product of the mycorrhiza. Glomalin is very resistant to destruction (recalcitrant) and difficult to dissolve in water. Its extraction requires specific conditions: high temperature (121°C) and a citrate buffer with a neutral or alkaline pH. Due to these properties, glomalin (or its fractions) are very stable compounds that protect the soil aggregate surface. In this review, the actual literature has been researched and the importance of glomalin is discussed.  

Effect of Organic Amendments on the Evolution of Soil Organic Matter in Soils Stressed by Intensive Agricultural Practices

2013 ◽  
Vol 17 (24) ◽  
pp. 2998-3005 ◽  
Author(s):  
Riccardo Scotti ◽  
Pellegrino Conte ◽  
Anne Berns ◽  
Giuseppe Alonzo ◽  
Maria Rao
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Organic Amendments ◽  
Agricultural Practices

Susceptibility of Groundwater to Pesticide and Nitrate Contamination in Predisposed Areas of Southwestern Ontario

1995 ◽  
Vol 30 (3) ◽  
pp. 443-468 ◽  
Author(s):  
Wray Lampman
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Crop Rotation ◽  
Agricultural Land ◽  
Monitoring Program ◽  
Agricultural Practices ◽  
Crop Rotations ◽  
Pesticide Contamination ◽  
The Impact

Abstract Agricultural practices today employ a vast array of chemicals in large volumes in order to improve both the quantity and quality of our agricultural products. While it has long been recognized that runoff from agricultural land has the potential to degrade surface water quality, only recently has attention been focused on the effect of agricultural usage on groundwater. In order to study the effects of pesticides and nitrate usage on the quality of groundwater, in 1985 the Ontario Ministry of Environment and Energy began operating a groundwater monitoring program in southwestern Ontario. Data generated from this program, which utilized sample data collected from both wells and piezometers, indicate that in areas of heavy pesticide and nitrate usage, shallow groundwater is continuously testing positive for nitrate and a variety of pesticides. Factors which influence the number of positive incidents for pesticides are directly related to the persistence of the chemical, its method of application, and the amounts utilized. Soil types and depth to groundwater, although influencing the time of detection, do not govern the number of detection events. Changes in agricultural practices are also monitored to see if pesticide reduction, a variation in the method of application, crop rotations and an increase in soil organic matter could influence the levels of pesticide It was found that when chemicals of a low persistence were applied post emergent at the minimum recommended rate, pesticides were not detected in the groundwater. Crop rotations were also effective in reducing the level of pesticides in groundwater. Tillage practices and increases in soil organic matter were also effective in reducing pesticide contamination. It was found that when chemicals of a low persistence were applied post emergent at the minimum recommended rate, pesticides were not detected in the groundwater. Crop rotation and reduction in nitrate loadings were found to be the only effective methods to reduce nitrate loading to groundwater. It was also found that elevated levels of potassium and/or nitrate in groundwater serve as a reliable indicator of the groundwater susceptibility to pesticide contamination. Remedial action to alleviate the impact of pesticides and nitrates in groundwater must focus on the chemical usage patterns employed on the farm site and an overall reduction of the quantities of pesticides and nitrates utilized. These patterns must incorporate a well-designed program of crop rotation with the proper utilization of these chemicals on site.

Modelling soil organic matter at long-time and landscape scales.

2021 ◽  
Author(s):  
Benjamin Bruneau ◽  
Benoit Chauveau ◽  
Julien Coatléven
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Large Scale ◽  
Transport Model ◽  
Agricultural Practices ◽  
Sedimentary Records ◽  
Long Time ◽  
Landscape Scales ◽  
Landscape Dynamic

<p>Understanding and simulating the soil organic matter had become a key challenge to better predict the landscape dynamic and its evolution. Although numerical modelling developments already integrate soil organic matter to improve agricultural practices at field or plot scales, additional work needs to be carried out to describe the landscape evolution over hundreds to thousands of years.</p><p>We aim to identify and quantify the processes associated to organic matter cycle that take part in landscape long-term evolution. We complete a reference sediment transport model designed for large scale evolution by adding some physical considerations relative to organic matter behaviour. The main developments concern:</p><ul><li> Organic matter productivity and its export to soils</li> <li> Organic matter evolution and degradation along soil profile and during transport</li> <li> Rock and regolith compartments with different lithologies and compositions</li> <li> Weathering and erosion</li> </ul><p>In this presentation, we explore the strengths and limits of this model designed to address a wide variety of questions in various settings. We also discuss the results and assess the validity of this approach considering availability of long-term sedimentary records.</p>

scholarly journals Reviews and syntheses: The mechanisms underlying carbon storage in soil

2020 ◽  
Vol 17 (21) ◽  
pp. 5223-5242 ◽  
Author(s):  
Isabelle Basile-Doelsch ◽  
Jérôme Balesdent ◽  
Sylvain Pellerin
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Abiotic Factors ◽  
Agricultural Practices ◽  
Turnover Time ◽  
Carbon Turnover ◽  
Soil C ◽  
C Dynamics ◽  
C Stocks

Abstract. Soil organic matter (OM) represents a key C pool for climate regulation but also an essential component for soil functions and services. Scientific research in the 21st century has considerably improved our knowledge of soil organic matter and its dynamics, particularly under the pressure of the global disruption of the carbon cycle. This paper reviews the processes that control C dynamics in soil, the representation of these processes over time, and their dependence on variations in major biotic and abiotic factors. The most recent advanced knowledge gained on soil organic matter includes the following. (1) Most organic matter is composed of small molecules, derived from living organisms, without transformation via additional abiotic organic polymerization; (2) microbial compounds are predominant in the long term; (3) primary belowground production contributes more to organic matter than aboveground inputs; (4) the contribution of less biodegradable compounds to soil organic matter is low in the long term; (5) two major factors determine the soil organic carbon production “yield” from the initial substrates: the yield of carbon used by microorganisms and the association with minerals, particularly poorly crystalline minerals, which stabilize microbial compounds; (6) interactions between plants and microorganisms also regulate the carbon turnover time and therefore carbon stocks; (7) among abiotic and biotic factors that regulate the carbon turnover time, only a few are considered in current modeling approaches (i.e., temperature, soil water content, pH, particle size, and sometimes C and N interactions); and (8) although most models of soil C dynamics assume that the processes involved are linear, there are now many indications of nonlinear soil C dynamics processes linked to soil OM dynamics (e.g., priming). Farming practices, therefore, affect soil C stocks not only through carbon inputs but also via their effect on microbial and organomineral interactions, yet it has still not been possible to properly identify the main mechanisms involved in C loss (or gain). Greater insight into these mechanisms and their interdependencies, hierarchy and sensitivity to agricultural practices could provide future levers of action for C sequestration in soil.

Sign in / Sign up

Export Citation Format

Share Document