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
2020 ◽  
Vol 15 (No. 2) ◽  
pp. 67-74 ◽  
Author(s):  
Vítězslav Vlček ◽  
Miroslav Pohanka

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.  


2017 ◽  
Vol 423 (1-2) ◽  
pp. 363-373 ◽  
Author(s):  
Emily E. Oldfield ◽  
Stephen A. Wood ◽  
Mark A. Bradford

2020 ◽  
Author(s):  
Beatrice Giannetta ◽  
Ramona Balint ◽  
Daniel Said-Pullicino ◽  
César Plaza ◽  
Maria Martin ◽  
...  

<p>Redox-driven changes in Fe crystallinity and speciation may affect soil organic matter (SOM) stabilization and carbon (C) turnover, with consequent influence on global terrestrial soil organic carbon (SOC) cycling.<span> </span>Under reducing conditions, increasing concentrations of Fe(II) released in solution from the reductive dissolution of Fe (hydr)oxides may accelerate ferrihydrite transformation, although our understanding of the influence of SOM on these transformations is still lacking.<span> </span></p><p>Here, we evaluated abiotic Fe(II)-catalyzed mineralogical changes in Fe (hydr)oxides in bulk soils and size-fractionated SOM pools (for comparison, fine silt plus clay, FSi+Cl, and fine sand, FSa) of an agricultural soil, unamended or amended with biochar, municipal solid waste compost, and a combination of both.<span> </span></p><p>FSa fractions showed the most significant Fe(II)-catalyzed ferrihydrite transformations with the consequent production of well-ordered Fe oxides irrespective of soil amendment, with the only exception being the compost-amended soils. In contrast, poorly crystalline ferrihydrite still constituted <em>ca. </em>45% of the FSi+Cl fractions of amended soils, confirming the that the higher SOM content in this fraction inhibits atom exchange between aqueous Fe(II) and the solid phase. Building on our knowledge of Fe(II)-catalyzed mineralogical changes in simple systems, our results evidenced that the mechanisms of abiotic Fe mineral transformations in bulk soils depend on Fe mineralogy, organic C content and quality, and organo-mineral associations that exist across particle-size SOM pools. Our results underline that in the fine fractions the increase in SOM due to organic amendments can contribute to limiting abiotic Fe(II)-catalyzed ferrihydrite transformation, while coarser particle-size fractions represent an understudied pool of SOM subjected to Fe mineral transformations.<span> </span></p>


Chemosphere ◽  
2007 ◽  
Vol 68 (7) ◽  
pp. 1245-1253 ◽  
Author(s):  
Julien Sebastia ◽  
Jérôme Labanowski ◽  
Isabelle Lamy

1969 ◽  
Vol 100 (2) ◽  
pp. 123-140
Author(s):  
Ian C. Pagán-Roig ◽  
Joaquín A. Chong ◽  
José A. Dumas ◽  
Consuelo Estévez de Jensen

The objective of this work was to measure the effects of repeated short-term organic amendments that we termed soil treatment management cycles (STMC) on physical and biological properties of a San Antón series soil. Each STMC lasted 60 days and consisted of incorporating 5% organic matter from coffee pulp compost; the planting, growth and incorporation of an intercrop of four green manure species; and the application of mycorrhizae and compost tea. The treatments were labeled: CL0, CL1, CL2 and CL3; where CL0 was the control, CL1 received one STMC, CL2 and CL3 received two and three STMC, respectively. The STMC intended to mimic the overall effect of a sustainable agricultural system, not to measure the individual effects of the practices. All treatments (CL1, CL2, CL3) showed an increase in soil organic matter (p≤0.05). When compared to the CL0 control, saturated hydraulic conductivity increased and bulk density decreased in all soils. Soil macroporosity was significantly increased by CL2 and CL3. Soil aggregate stability increased in CL1, CL2 and CL3 plots. Microbial biomass C increased in treatment CL3, and microbial biomass N increased in CL2 and CL3. The production of stable aggregates was correlated to humic acid content and positively influenced all other physical parameters assessed in this study. The STMC had a positive impact on soil properties by increasing the soil organic matter as well as the humic acid fraction. Soil macroporosity, defined as porosity with radius > 38 µm, was significantly increased by treatments CL2 and CL3. All of the organic matter fractions, including total organic matter, humic acid content, microbial biomass C and microbial biomass N were significantly increased by one or more STMC.


1995 ◽  
Vol 30 (3) ◽  
pp. 443-468 ◽  
Author(s):  
Wray Lampman

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.


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