Excitation−emission matrix (EEM) fluorescence spectroscopy has been widely used to characterize dissolved organic matter (DOM) in water and soil. However, interpreting the >10,000 wavelength-dependent fluorescence intensity data points represented in EEMs has posed a significant challenge. Fluorescence regional integration, a quantitative technique that integrates the volume beneath an EEM, was developed to analyze EEMs. EEMs were delineated into five excitation−emission regions based on fluorescence of model compounds, DOM fractions, and marine waters or freshwaters. Volumetric integration under the EEM within each region, normalized to the projected excitation−emission area within that region and dissolved organic carbon concentration, resulted in a normalized region-specific EEM volume (Φi,n). Solid-state carbon nuclear magnetic resonance (13C NMR), Fourier transform infrared (FTIR) analysis, ultraviolet−visible absorption spectra, and EEMs were obtained for standard Suwannee River fulvic acid and 15 h...

Fluorescence excitation-emission matrix regional integration to quantify spectra for dissolved organic matter.

Biochar as a sorbent for contaminant management in soil and water: a review.

Characterization of marine and terrestrial DOM in seawater using excitation-emission matrix spectroscopy

Climate change 2014 - Synthesis Report

Rapid turnover of organic matter leads to a low efficiency of organic fertilizers applied to increase and sequester C in soils of the humid tropics. Charcoal was reported to be responsible for high soil organic matter contents and soil fertility of anthropogenic soils (Terra Preta) found in central Amazonia. Therefore, we reviewed the available information about the physical and chemical properties of charcoal as affected by different combustion procedures, and the effects of its application in agricultural fields on nutrient retention and crop production. Higher nutrient retention and nutrient availability were found after charcoal additions to soil, related to higher exchange capacity, surface area and direct nutrient additions. Higher charring temperatures generally improved exchange properties and surface area of the charcoal. Additionally, charcoal is relatively recalcitrant and can therefore be used as a long-term sink for atmospheric CO2. Several aspects of a charcoal management system remain unclear, such as the role of microorganisms in oxidizing charcoal surfaces and releasing nutrients and the possibilities to improve charcoal properties during production under field conditions. Several research needs were identified, such as field testing of charcoal production in tropical agroecosystems, the investigation of surface properties of the carbonized materials in the soil environment, and the evaluation of the agronomic and economic effectiveness of soil management with charcoal.

http://www.css.cornell.edu/faculty/lehmann/publ/BiolFertSoils%2035,%20219-230,%202002%20Glaser.pdf

Ameliorating physical and chemical properties of highly weathered soils in the tropics with charcoal – a review

Molecular and quantitative aspects of the chemistry of fulvic acid and its interactions with metal ions and organic chemicals : Part I. The electron spin resonance approach

Synchronous excitation fluorescence spectroscopy applied to soil humic substances chemistry

The main scope of the wide use of organic amendments of various origin and nature in modern agriculture is to increase and/or restore the organic matter content in organically poor or depleted soils in order to maintain and/or increase crop production and reduce soil exposure to degradation, erosion, desertification and pollution. The agronomically efficient and environmentally safe use of any organic amendment requires, however, an adequate control not only of the chemical quality of the humic substance (HS)-like fractions contained, which is an important indicator of the maturity and stability achieved by organic matter in the amendment, but also of the effects that these HS may have on native soil HS. In this review, the most recent results obtained on this topic by the research groups operating in Bari, Italy, and in Madrid, Spain, are discussed comparatively with results recently published by other research groups. Overall, HS-like components of organic amendments are characterized by higher aliphatic character and molecular heterogeneity, lower contents of O, acidic functional groups and organic free radicals, and lower degrees of aromatic ring polycondensation, polymerization and humification than native soil HS. These differences are less evident for composted materials. The composition, structure and functionalities of HS in amended soils may be affected in different ways and at various extents on dependence of the nature, origin and rate of amendment. In general, these properties are intermediate between those of the unamended soil HS and the HS-like fractions in the amendment, but generally resemble more the former than the latter, especially with increasing time after amendment application.

A comparative survey of recent results on humic-like fractions in organic amendments and effects on native soil humic substances

Publisher Summary This chapter reviews the chemical and physicochemical data available for the evaluation on a molecular scale of the humic substances (HS) like components in organic amendments of various origins and nature, and the effects of added HS-like materials on the composition, structure, and chemical reactivity of native soil HS. The organic amendments are discussed based on four classes: sewage sludge; municipal solid wastes; animal manures; and plant, wood, and food industry residues. Soil application of mature, stabilized, and partially humified organic wastes of any nature and origin affects the composition, structure, and chemistry of native soil HS. These modifications are more extensive and lasting in the fulvic acid (FA) fraction than in the humic acid (HA) fraction of an amended soil. The proteinaceous, S-containing, lignin, and aliphatic structures contained in HS of organic amendments are extensively incorporated into native soil HS in forms relatively resistant to further decomposition. The chapter also summarizes the scope of the treatment processes of organic wastes intended to produce soil amendments with beneficial properties for agriculture.

Nicola Senesi

Papers

Molecular and quantitative aspects of the chemistry of fulvic acid and its interactions with metal ions and organic chemicals : Part I. The electron spin resonance approach

Synchronous excitation fluorescence spectroscopy applied to soil humic substances chemistry

A comparative survey of recent results on humic-like fractions in organic amendments and effects on native soil humic substances

Humic-like Substances in Organic Amendments and Effects on Native Soil Humic Substances

Determination of heavy metals in soils by Laser Induced Breakdown Spectroscopy