MOSES Management Fundamental Processes

Inclosed is my summary of the current status of MOSES management processes.

INTRODUCTION:

Each MOSES "operation" is defined as a list of physical "processes" representing the actual action(s) performed by the "operation". Thus, MOSES should be able to handle any operation, if all the fundamental processes required to represent the operation's actions are available within MOSES. Therefore, the definitions of all necessary fundamental physical processes required by the erosion models are listed.

Definition of a MOSES Process:

A MOSES process is defined as a process which reflects a physical change in some property or group of properties relating to the soil, surface, vegetation, residue, or any other material that impacts the ARS erosion models' representations of the soil/surface/vegetation/residue states.

MOSES Process Classifications:

• Soil Surface Modification
• The soil surface state is described differently within each of the erosion models. However, each model still represents the surface state condition as a unique set of variables, even though some of those variables may be influenced by other processes and properties.

• Soil Mass (layer) Manipulation
• The soil mass (represented as a series of stacked, parallel, homogeneous horizontal layers in some of the erosion models) is moved and changed by many management operations. The soil mass (density, aggregate size and stability, etc.) and quantity and location of soil properties (sand, silt, clay, organic matter, etc.) define the state of the soil.
• Biomass Manipulation
• The biomass manipulation processes describe the effects that management operations have on the growing crop and residue pools in the models. The types of processes here involve the transfer of biomass from standing to flat, live to dead, above ground to buried, buried to surface, etc.
• Soil Amendments
• The addition of specific materials to the soil and/or surface fall into this category. Typical processes here would include such things as the application of water (irrigation), nutrients (fertilizers), and residues.

MOSES Processes (soil surface manipulation):

• Create/Modify Random Roughness

• The roughness index used will be the standard deviation of the roughness height.
• Provisions will be made to allow "relative" or "absolute" changes to surface roughness as well as the possibility of one or the other dependent upon other influences, e.g. tillage depth or pre-operation roughness. In this context, "relative" means an increase or decrease of random roughness after an operation based upon the pre-operation roughness and "absolute" means a change to a fixed random roughness regardless of the pre-operation surface condition.
• The "relative" roughness parameter could be based upon a "tillage intensity" factor.
• The "percent of surface disturbed" by the operation would be a random roughness process parameter.

• Create/Modify Ridges

• Ridges are fully defined within MOSES with the following information: ridge direction (row direction), ridge height, ridge spacing, ridge top width, and ridge side slope.
• Provisions will be provided to allow the user to specify whether an implement can completely destroy ridges if they exist or if the operation will only partially destroy (modify) them. This could also be based upon a "tillage intensity" factor.

•  Create/Modify Dikes
• Dikes exist only when ridges exist.
• Dikes are fully described within MOSES with the following information: dike height, dike spacing, and dike side slope.
• All provisions pertaining to the destruction of ridges also pertains to the destruction of dikes.

• Create/Modify Crust
• Will occur with any soil disturbance process (i.e., crust will always be destroyed).
• Could be used as a special independent process for testing/debugging a model.

Things that will not be part of the soil surface manipulation processes domain:

• Decay of random roughness - this is left up to the erosion models to deal with
• Long-term minimum random roughness - again this is left up to the individual models to address

MOSES Processes (soil mass manipulation):

• Loosen/Compact Soil
• Changes in soil layer bulk density within the "zone of influence" due to an operation is represented by this process.
• Changes in soil layer bulk density due to climatic effects are not represented by this process but are dealt within each specific erosion model.
• Tillage depth determines the "zone of influence", i.e. soil layers affected.

• Mixing Among Soil Layers
• The mixing process represents the uniting or blending of soil layer properties within the soil layers only.
• The burial (or resurfacing) of constituents such as crop residue are not represented by this process.
• Tillage depth determines the soil layers that will be mixed.
• Tillage tool will determine the degree and distribution of mixing.
• All pertinent soil layer properties (sand, silt, clay, OM, etc.) as well as nutrients and residues within those layers can be mixed as deemed appropriate by each individual erosion model.
• Inverting Soil Layers
• The inversion process is the reversal of the vertical order of soil layers within the working depth of the tillage tool.
• This could be considered a "special case" of the mixing process.
• Modification of Soil Layer Aggregate Size Distributions
• Aggregate size distribution (ASD) is a soil layer property.
• It is treated similar to any other physical soil layer property, e.g. clay content or residue.
• Aggregates can be mixed among layers, thus changes in ASD can occur in a layer even if no construction/destruction of aggregates occur.
• Aggregates can be created and/or destroyed by an operation.

• Tillage depth determines the soil layers that are affected.
• The type of tillage tool will determine the degree of change in ASD for each soil layer.
• Currently, only WEPS requires this soil property.
• Movement of Soil Laterally Between Rill and Interill Areas
• This process was included in George Foster's list. I believe it was there because WEPP has this process.

MOSES Processes (biomass manipulation):

• Grow
• Initiate crop growth.
• Will usually be a part of all seeding/planting operations.
• Kill
• Stop the growth of biomass.
• Many harvest operations will include this process.
• The process may also occur elsewhere within a model due to crop maturity, severe stress, etc.
• Remove
• Removing biomass (or other material) from the field.
• Harvesting operations will naturally include this process.
• What is removed and how much will be specified by the parameters for this process.
• Cut
• Cutting standing biomass to a prescribed height.
• The biomass above the "cut" height will either be removed or added to the appropriate surface flat biomass pool.
• The cut process will contend with cutting heights specified from the surface up as well as those specified from the crop height down.
• Flatten
• Moving a portion of the standing biomass to the soil surface.
• Bury/Lift
• Transferring above ground biomass into the soil or the inverse process of bringing buried biomass to the surface.
• Shred
• This is a process that George Foster had in his list.
• In essence, this process is changing the properties of the biomass that is being affected, e.g. it makes a residue more fragile, thus more susceptible to decomposition.

MOSES Processes (soil amendments):

• Addition of specific materials to the soil and/or surface.
• manufactured nutrients such as nitrogen, phosphorous, etc.
• manure
• irrigation water
• biomass (residue)
• Controlled Drainage
• Process included in George Foster's list.

Goto MOSES WEB Server (Lubbock, TX)