Agriculture

The agricultural module of ALCES® tracks the area of several different agricultural cover types including tame pasture, oilseed crops, cereal crops, forage crops, tuber crops, root crops, and fallowed land.. Feedlots are an example of an agricultural footprint type tracked in ALCES®. A suite of variables are tracked for each agricultural type, including livestock (cattle, pigs, sheep separately) density, manure production, productivity of various crop types (cereals, oilseeds, tuber, legumes, specialty, etc) and management input requirements for fertilizers (nitrogen, phosphorus), insecticides, herbicides, and irrigation water. ALCES® recognizes that a given parcel of agricultural land often rotates among different crop types and allows the identification of crop rotation composition and rotation intervals. Several different rangeland types are tracked in ALCES®, and these cover types can change in structural complexity as a function of grazing intensity, fire, and precipitation. ALCES® allows the specification of recommended stocking rates for each rangeland type, and the specification of how various stocking rates influence rangeland structural stage. Agricultural relationships can be simulated in constant or stochastic mode. Stochastic noise in the agricultural model is driven by inter-annual variation in precipitation and temperature.

Output variables relating to the agricultural sector generated by ALCES® for each time step and in each landscape type, include:

• crop area (ha) and edge (km);
• annual and cumulative crop production (tonne/yr);
• annual and cumulative crop inputs (nitrogen, phosphorus, insecticides, pesticides (each tonne/ha/yr); water applications (m3/ha/yr));
• annual and cumulative livestock production;
• annual and cumulative forage requirements for livestock populations
• number of livestock animal units residing on each cover type and in feedlots;
• existing (area (ha), edge (km)) of seismic lines, wellsites, pipelines, surface mines, and processing facilities);
• annual direct jobs, indirect jobs, and revenues associated with the agricultural sector
• annual emissions (tonnes/year) of atmospheric compounds including NOX, SOX, VOC, PAH, particulates, etc.;
• annual runoff of nitrogen, phosphorus and sediment (tonne/ha/year) associated with each agricultural landscape type; and
• annual gross and net water requirements (m3) for each of croplands and livestock extracted from each of surface water (lentic, lakes, and reservoirs) and aquifers.

Table inputs

1.  Crop rotation metrics
- For each crop type, enter "1" if the crop type is part of a crop rotation strategy; enter "0" if it is not.
- For each crop type, enter the length of the rotation in years.

2.  Composition of agricultural landscape type rotation
For each crop type specified to be part of a rotation strategy (Table 1 "Crop rotation metrics"), enter the percent composition (0 to 1) of crop types comprising the rotation.  For example, in a rotation strategy involving forage crops, 40% may be forage crops, 35% cereal crops, and 25% improved pasture.

3.  Initial population and distribution of livestock
- Enter the initial population of cattle, swine and horses in the land base at the start of the simulation period.
- For each livestock species, enter the proportion (0 to 1) of the population that occurs on each cover type.

4.  Livestock weight and production rates
- For each livestock species, enter the average weight (kg) per animal.
- For each livestock species, enter the average number of animals per animal unit (AU).
- For each livestock species, enter the average population turnover (proportion, 0 to 1).

5.  Percentage of feedlots by species
For each livestock species, enter the proportion (0 to 1) of the population occurring on feedlots.

6.  Irrigation metrics
Enter the proportion (0 to 1) of irrigation water lost to leakage and evaporation.

7.  Non-irrigated and irrigated cropland production rates
- For each crop type, enter the average irrigated production rate (Tonne / hectare / year)
- For each crop type, enter the average non-irrigated production rate (Tonne / hectare / year)
- For each crop type, enter the average number of years between fallowing.  Enter '0' if no fallowing occurs.

8.  Distribution of cattle population growth among cover types
Enter the proportion (0 to 1) of cattle growth that occurs on each cover type.

9.  Distribution of swine population growth among cover types
Enter the proportion (0 to 1) of swine growth that occurs on each cover type.

10.  Distribution of horse population growth among cover types
Enter the proportion (0 to 1) of horse growth that occurs on each cover type.

11a.  Recommended stocking rate for cattle
For each cover type, enter the recommended cattle density (animals per km2).

11b.  Recommended stocking rate for swine
For each cover type, enter the recommended swine density (animals per km2).

11c.  Recommended stocking rate for horses
For each cover type, enter the recommended horse density (animals per km2).

12.  Livestock growth trajectory
- For each livestock species, enter the population growth modifier.  The population growth rate is multiplied by this modifier value.  For example, a value of 0.5 would reduce the population growth rate by 50%; a value of 2 would double the population growth rate.
- For each livestock species, enter the initial population modifier.  The initial population specified in Table 3 "Initial population and distribution of livestock" is multiplied by this modifier value.  For example, a value of 0.5 would reduce the initial population by 50%; a value of 2 would double the initial population.
- Enter the footprint development level with respect to the graphic input device for feedlots.

Graphic inputs

Temporal change in non-irrigated crop production rates
For each year of the simulation period, enter the relative change in the non-irrigated crop production rate compared to the rate at the start of the simulation.  A value of 0.5 indicates crop production rate is half of that indicated by the "Herbaceous growth (tonne/ha) trajectory" value for each crop type.  A value of 1.5 indicates a 50% increase.  A value of 1 indicates no change.

Temporal change in irrigated crop production rates
For each year of the simulation period, enter the relative change in the irrigated crop production rate compared to the rate at the start of the simulation.  A value of 0.5 indicates crop production rate is half of that indicated by the "Herbaceous growth (tonne/ha) trajectory" value for each crop type.  A value of 1.5 indicates a 50% increase.  A value of 1 indicates no change.

User defined agricultural trends

User defined temporal changes include possible growth in the size of the agricultural landscape, the growth in each of the agricultural cover types, stocking rates of cattle on rangelands, and proportional growth of feedlots.  Growth of agricultural cover types is defined as a range of permissible percentages ranging from +10 to -10% = -0.1 to +0.1) annually throughout the simulation interval.  If agricultural cover types are to grow or decline in area during a simulation, it is necessary to specify which agricultural landscape types they will grow into or be consumed by.

Graphic inputs

Change in livestock density relative to initial density
For each livestock species, specify the population growth rate during each year of the simulation period.  Values may range from a 5% decrease (-0.05) to a 5% increase (+0.05).  If the Switch "Livestock Density Limit" for that species is turned on (up), then the model will stop growing a livestock population once it has achieved the maximum recommended stocking density on a given landscape type. The density limit switch does not apply to footprint types (e.g., feedlots).

Confined feeding operation area growth rate
Specify the annual growth (in percent) of feedlots during each year of the simulation period.  Values may range from 0 to 1 (100%).  If non-zero values are entered here, then all values in the Graphic Input "Annual growth of feedlots" must be zero.

Annual growth of confined feeding operations
Specify the annual growth (hectares per year) of feedlots during each year of the simulation period.  If non-zero values are entered here, then all values in the Graphic Input "Confined feeding operation area growth rate" must be zero.

CFO size vs buffer
For each livestock species, enter the average buffer radius around confined feeding operations (CFO) of different herd sizes.  This relationship is used to calculate the amount of area that is considered uninhabitable in the land base because of proximity to CFOs.

Average number of animals in a confined feeding operation
For each livestock species, enter the average number of animals per confined feeding operation during each year of the simulation period.