Buffer capacity andCuaffinity of soil particulate organic matter (POM) size fractions
نویسنده
چکیده
Particulate organic matter fractions (POM), defined as sand-sized organic separates in soils, are known to be labile organic components with a rapid turnover. Recently, POM fractions were identified to be metalenriched in both metal-contaminated and uncontaminated soils. However, mechanisms for such metalenrichment are poorly understood, because of the paucity of information on the chemical properties of POM. The aim of this study was to quantify the reactivity of POM towards Cu and to show a POM-size effect on this reactivity. POM was isolated from soils with different organic amendment managements: straw (S), conifer compost (CC), and non-amended (NA). Two POM size fractions were isolated by density-fractionation in water: 50–200 mm and 200–2000 mm. These fractions were studied for their metal contents, acid-base properties and affinity toward Cu. The buffer capacity and Cu affinity were modeled by FITEQL 4.0 software and compared between the two POM size fractions. Each POM size fraction provided a buffer capacity due to the presence of reactive sites, the greatest being for the 50–200 mm POM fractions. A signature of organic inputs as seen by the buffer capacities was observed for the 50–200 mm but not for the 200–2000 mm POM fractions. But Cu affinity was comparable between the coarse and fine POM fractions and no significant differences were found between NA, S and CC samples. We checked the hypothesis that decreasing POM size due to degradation processes generates more reactive surface sites. Results confirmed that soil POM plays a key role as a metal sink, due to its chemical properties.
منابع مشابه
Influence of organic amendments on copper distribution among particle-size and density fractions in Champagne vineyard soils.
The intensive use for over 100 years of copper sulfate (Bordeaux mixture) to fight against mildew in vineyard soils has led to an important, widespread accumulation of Cu (100 to 1500 mg Cu kg-1 soil). In Champagne vineyards, organic amendments are used currently to increase soil fertility and to limit soil erosion. Organic amendments may have a direct effect on the retention of Cu in the soil....
متن کاملOrganic matter turnover in soil physical fractions following woody plant invasion of grassland: Evidence from natural
Soil physical structure causes differential accessibility of soil organic carbon (SOC) to decomposer organisms and is an important determinant of SOC storage and turnover. Techniques for physical fractionation of soil organic matter in conjunction with isotopic analyses (dC, dN) of those soil fractions have been used previously to (a) determine where organic C is stored relative to aggregate st...
متن کاملChange of Soil Carbon Fractions and Water-Stable Aggregates in a Forest Ecosystem Succession in South China
In order to evaluate the dynamics of carbon storage during forest succession and explore the significance of water relations and soil stability in forest environments, a study was conducted in 2011. This study investigated the dynamics of soil organic carbon (SOC) fractions and its protection through aggregation along the successional forests. An experiment in South China examined pine forest (...
متن کاملActivities of extracellular enzymes in physically isolated fractions of restored grassland soils
Extracellular enzymes degrade complex organic compounds and contribute to carbon turnover in soils. We used physical fractionation procedures to investigate whether soil carbon is spatially isolated from degradative enzymes across a prairie restoration chronosequence in Illinois, USA. We found that carbon-degrading enzymes were abundant in all soil fractions, including macroaggregates, microagg...
متن کاملOrganic matter stabilization in a Xanthic Ferralsol of the central Amazon as affected by single trees: chemical characterization of density, aggregate, and particle size fractions
Ž . Not only the amount of organic carbon in soil is important for soil organic matter SOM stability, but also its physical and chemical properties. The appropriate technique for the assessment of SOM dynamics can vary between soil types, and information about this is lacking for Ferralsols of the central Amazon basin. First, this work identified SOM pools which are sensitive to land-use change...
متن کامل