Economy Model


By default prices are fixed at $250 per ton for alfalfa, $150 per ton for corn, and $80 for grass and do not change over the course of the game. However, the moderator has the option to enable a dynamic market economy.

The Field's of Fuel dynamic economy model is a supply and demand model driven by two commodities: fuel and animal feed, where animal feed is subject to an elastic market. The supply of each commodity is determined each year by player decisions—the total crop yield for all players is converted to fuel or feed, and compared to that year's demand. The annual demand for each commodity is determined by a random sampling from a normal distribution, in order to simulate the random nature of market demands (due to uncontrollable effects such as abnormally cold winters, or global droughts, etc). Due to a continually increasing global demand for energy, the mean demand for fuel increases by 5% each year. Furthermore, the supply and demand market is tracked using a weighted, rotating three-year window. That is, the demand for each commodity each year is equal to this year's demand, plus half of last year's demand and a quarter of the next previous year's demand. Likewise, the commodity supply each year is the sum of this year's supply plus half of last year's supply and a quarter of the previous year's. As such, one year's surplus/shortage will effect crop prices for three continuous years, but with diminishing effect each year.

αf  ≝ percent of crop 'f' used to produce animal feed
CR≝ fuel conversion rate of crop 'f' (tons crop to L fuel)
S ≝ Elasticity of Substitution  [ R = (S-1) / S ]
( S = ∞ ⇒ Perfect Substitutions,  S = 0 ⇒ Perfect Complements )

Elastic Feed Market

Within the Field's of Fuel market, there are three possible sources for producing animal feed: alfalfa, corn silage, and corn stover. Due to differences in nutritional value, these feed sources are not perfectly replaceable—that is, there is some elasticity of substitution within the feed market. The annual feed market demands call for a specific ratio of feed sources (set by the share parameter, af). To reflect this demand, prices of alfalfa and corn are determined by not only the relative surplus/shortage of feed in the market, but also by the relative distribution of feed sources (π). For example consider a situation where there is a shortage of feed in the market, and the relative ratios of feed grown is 80% alfalfa, 20% stover, and 0% silage. In this case, all three would experience a price increase due to the feed shortage, but alfalfa prices experience only a very small increase, whereas the price of corn silage would increase tremendously (which would then be reflected in the overall corn price).



Commodity prices are determined as a percent of a base value, based on their marginal values (λ) that year (determined by the severity of the current year's supply or shortage).

Crop prices are then determined based on a weighted average of the prices of the commodities they produce. For corn, the relative price weighting is determined based on where corn is demanded in the market—the distribution of corn sales (β) will automatically be distributed among the two commodities to best meet the market demands (minimize the excess demand). Thus, if corn is used predominately to produce fuel, its price will more closely match current fuel prices, whereas if corn is used more for feed, its price will more closely match feed prices.

*Note: Because half of all corn stover is plowed back into the ground, corn grain prices have a greater impact on corn prices than corn stover prices.


Parameter Value Units
CR(veg) 0.38 L/Ton
CR(grain) 0.4 L/Ton
S 2.5 N/A
a(stover) 0.2 N/A
a(grain) 0.4 N/A
a(alfalfa) 0.4 N/A
Base Price (Feed) 250 $/Ton
Base Price (Fuel) 0.225 $/L




A player's capital is the sum of his/her total net revenue over all the years of gameplay.


The profit earned on each field is simply the total yield of crop sold at its market price that year according to the market.



Per field costs are computed according to the following parameters:


Action Cost ($/acre)
Establish 422.04
Continue N/A
Fertilize (high) 103.57
Fertilize (low) 51.79
Till 44.96


Action  Cost ($/acre)
Establish  268.73
Continue 182.16
Fertilize (high)  44.66
Fertilize (low)  0
Till  N/A


Action  Cost ($/acre)
Establish  279.02
Continue 185.59
Fertilize (high) 0
Fertilize (low)  0
Till  N/A