Dear Michael,

I have never heard the term 'soil organic matter structure'. There is term 'soil structure' which refers to relative proportion of sand, silt and clay in the soil. The stability of soil structure is improved  by organic matter of the soil.

Good luck 

I think you are talking about the composition of organic matter.

http://agriinfo.in/?page=topic&superid=5&topicid=169

http://aciar.gov.au/files/node/334/soil_organic_matter_management_for_sustainable_agr_20481.pdf

https://webcache.googleusercontent.com/search?q=cache:HptQa-P-jOQJ:https://www.researchgate.net/file.PostFileLoader.html%3Fid%3D560df4db5cd9e36e368b4567%26assetKey%3DAS%253A279943859720210%25401443755225688+&cd=10&hl=en&ct=clnk&gl=sa

Soil structure refers to the shape and size of aggregates. The aggregates are made up of both the mineral (sand, silt, and clay) and organic fractions of the soil. Aggregates are generally held together by root exudates, fungal hyphae, and other organic material. Soil structure can generally be classified as being single grain, granular, blocky, platy, columnar, or massive.

If you want to describe the proportions of sand, silt, and clay in a soil, that is soil texture.

Dear Michael,

I regret for defining the soil structure as soil texture. Soil structure refers to the arrangement of soil particles in aggregates. Organic matter is helpful in improving the soil structure.

Good luck

Your question is not very clear....

If you refer to chemical structure of SOM you have different methods, chemical and physical ones. For example, you can burn the SOM & measure the heat emission; according the pics of  heat emissions you can infer the structure of the humic substances. Another way is following traditional chemical processes, using different basic solvents, pH, complexing power, etc. Please down load some of my papers dealing with.

Dear Michael, In the same light as Dr. Juan, i think  it is  clearer to talk about "forms of soil organic matter". Briefly, soil organic matter is very heterogeneous and for you to have an understanding of the various constituents, it will be important to consider SOM as a complex mixture consisting of  (1)Unaltered materials, which include fresh debris and non-transformed components of older debris (2)Transformed products, or humus, bearing no morphological resemblance to the structures from which they were derived (3) interaction between SOM  and other mineral (inorganic) soil constituents such as clay minerals. 

For more on this, try obtaining the book entitled "CHEMISTRY OF SOIL ORGANIC MATTER" by KYOICHI KUMADA. Developments in Soil Science 17, Japan Scientific society Press. 

Best wishes.

Combinations of spectroscopic techniques are used to characterise the structure of soil organics.  NMR is often used but it requires removal of Fe compounds which typically means extraction of the organic phase under alkaline, anoxic conditions and further purification before measurement.  Papers by Ashlea Doolette et al. may be at the leading edge.  EDAX, SIMS, IR and synchrotron spectroscopy allow less intrusive pre-analysis treatment.

Tell us first whats the question you want to answer?

 Am currently studying Acrostichum aureum and I will like to find out if these plants influence the organic matter structure of the sediment?

Furthermore, if you understand Spanish, you can read my book: SOIL ORGANIC MATTER, indeed.

Soil organic matter is amorphous in nature, therefore, no perfect lattice structure can be assigned to it. The soil organic matter is consisting of  macromolecules   of varying molecular weights. Electron microscopic studies (SEM) done with the extracted components of soil organic matter (Fulvic and humic acids) indicate that  these have flexible physical appearance which change with equilibrium pH and ionic strength. Spectroscopic studies like colour ratio (E4/E6), IR spectrocopy and 13C-NMR can reveal about the dominance of some chemical moieties in these natural acids. The elucidation chemical structure is also possible by studying the chemical or microbial degradation products of these acids.

There are lots of techniques to evaluate SOM, chemical, physical, spectroscopy methods... Depends on the specific processes or characteristic you want to access.

Here a review of many of this techniques and theirs applicability.

A lot of techniques are described in the book SOIL ORGANIC MATTER , if you can read Spanish.

Interesting discussion..

Abstract :With the widely used activated sludge treatment most of the organic matter (OM) of wastewater can be removed, but the composition and origin of the refractory OM in treated water are poorly known. The structures occurring in treated water are more difficult to elucidate than those of the OM originally present in wastewater, since the classical hydrolysis−chromatography methods are not suitable for the analysis of such samples. 13C and 15N solid-state Nuclear Magnetic Resonance (NMR), liquid-state 1H NMR and infrared (IR) were used in the present study. A treatment procedure including a stage of ozonation of the sludge, used to reduce the sludge production, was studied along with a conventional treatment line. The OM in the water treated through the ozonated line was mainly composed of proteins and sugars moieties, while the aliphatic compounds dominant in the wastewater were efficiently removed. The conventional treatment was more efficient in terms of OM removal but led to the formation and/or enrichment of unknown products with high oxidation and branching levels. These products contained C O groups, while the nitrogen was found in amide groups, refractory to the treatme. Source : Environ. Sci. Technol., 2000, 34 (16), pp 3389–3394 DOI: 10.1021/es9913838