I can readily think of two methods (there might be many more out there):

1- Jet Erosion Test. Essentially use a pressurized fluid to dig a scour hole whose geometry is related to soil erodibility.  http://biosystems.okstate.edu/home/gareyf/JETSpreadsheet.htm

2- Fluidized bed on intact cores. Fundamental of this method is that bed fluidization forces in excess of particle weight are the result of soil cohesion, related to soil erodibility.

Hope this helps.

SKN

Dear Nouwako

I looked at the Jet erosion test and realized it has to be connected to a tap, which is not so possible in the field. I will check out the second option. Not to ask too  much but do have any ideas on the suppliers for the the Jet?

Thanking you

Rosemary

I have never used the Jet Eorsion Test device before so I am not very familiar with its intricacies. I can however imagine using some form of regulated pump or constant head system with adequate water supply to implement the JET in the field. I believe this has been done in the past. If supplying enough water to your field site(s) is logistically impractical, you may consider bringing intact cores to be analyzed in the lab.

The fluidized bed method works really well on soils with moderate clay content (< 40%). You will have to design your own fluidization chamber since there is none commercially available and I will be more than happy to assist you with that. I refer you to these publications for more details on this technique:

SSSAJ Volume: 76 Issue: 4 Pages: 1192-1196

and the one attached.

Cheers,

SKN

Article Using fluidized bed and flume experiments to quantify cohesi...

Dear Nouwako

Thank you very much.

There is a portable rainfall simulator you could use for this:

http://pkd.eijkelkamp.com/Portals/2/Eijkelkamp/Files/Manuals/M1-0906e%20Rainfall%20simulator.pdf

With this device you can make a relative comparison between the erodibility of different sites in the field. You need to describe the different factors very well for this.

Dear Riksen

Thanks for your response. I was hoping for that one at the beginning but turns out to be a  little expensive for a PhD project, 6096.00 Euro. Hence looking at other alternatives now.

Dear Rosemayy,

A rough estimate of soil erodibility can be obtained taking into account texture, organic matter, structure and permeability, as proposed by Wischmeier and Smith (1978). Attached I include an article describing and using this method.

Cheers,

Joan

There are serveral aproaches offered to the person asking the question, but it is needed to know to what concrete erodibility definition the question refers. If we talk of the USLE/RUSLE K factor, the only alternative way to the use of simulated rain isn using the "long way" of colecting data under natural rain fora a long period, using standard runoff plots. If the question refers to other concept or definition of erodibility, used in otres models (for instance, in WEPP there are 2 erodibilities, one to rill and other to interrill erosion), or if it refers to a relative comparison between situations with different erosion suceptibility, the other procedures mentioned could be possible answers.

Thank you all for your support. I will definitely look into all the possibilities you mentioned.

Thank you.

Soil erodibility in vineyards on steep slopes were measured as was described in our article "Effect of soil management systems on erosion and nutrition loss in vineyards on steep slopes" J. Environ. Biol.

32, 289-294 (2011)

If you can get the data of radiocesium (137Cs) inventory (Bq m-2) at a local  reference (neither eroded nor deposited site) and at your place of interest, I can quickly think two possible ways to roughly estimate erodibility  factor.

1. Estimate the gross soil erosion rate by converting the cesium data using one of the appropriate conversion models indicated by Zapata (2002) and approximate this value to USLE/RUSLE and calculate the unknown K factor given other inputs  (rainfall, vegetation cover, slope,  slope-length etc) can be readily available  or estimated.

2. Could erodibility directly be approximated to = [1 - (mean137Cs  inventory at the point of interest/ 137Cs inventory at the reference site)]. Any comments and further discussions are welcome and appreciated for this equation.

I recommend a soil pocket Vane Shear (very cheap aprox $500). Easy to operate and you can obtain a lot of sample in few minutes.

You should care about the topsoil humidity in order to compare the data between sites.

Thomaz EL. 2013. Rill erosion on an oxisol influenced by a thin compacted layer. Revista Brasileira de Ciência do Solo, 37: 1383-1392. (open access).

Have a good research

Article Rill erosion on an oxisol influenced by a thin compacted layer