Quoted from:http://www.saga-gis.org/en/index.html

Soil erosion modelling with a modified MMF (Morgan-Morgan-Finney) model (Morgan & Duzant 2008).
This tool is called MMF-SAGA because some things have been implemented differently compared to the original publication. The most important are:

• the extension of the model to support spatially distributed modelling
• the introduction of a "Channel Network" layer
• the introduction of a "rainfall duration" (time span) parameter
• the exposure of the flow depth parameter

A more detailed description of the model, its modifications, and model application is provided by Setiawan (2012), chapter 6.
Currently, a number of additional grid datasets are outputted to facilitate model evaluation. This can be easily changed within the source code.


References:
Morgan, R.P.C. (2001): A simple approach to soil loss prediction: a revised Morgan-Morgan-Finney model. Catena 44: 305-322.

Morgan, R.P.C., Duzant, J.H. (2008): Modified MMF (Morgan-Morgan-Finney) model for evaluating effects of crops and vegetation cover on soil erosion. Earth Surf. Process. Landforms 32: 90-106.

Setiawan, M. A. (2012): Integrated Soil Erosion Management in the upper Serayu Watershed, Wonosobo District, Central Java Province, Indonesia. Dissertation at the Faculty of Geo- and Atmospheric Sciences of the University of Innsbruck, Austria.