Here is my "Topical Post". Keep in mind this is all pre-DF.31.
:: FEB-06-10 ::
I'd like to throw some chips in. But before we start, keep in mind I am not factoring in booze cooking for my initial food estimates. That comes later.
First stacking needs to be fixed. Once plants can be stacked together and barrels topped off, low per-tile crop yields will no longer be problematic from an inventory standpoint. I've heard that this can't be done and I've heard that this can be done, so I'm throwing it out there that beating the code with a sledgehammer until it begs forgiveness and neatly stacks items in its time-out corner is a worthwhile pursuit, damn the torpedoes. This is not required for my arguement, but it seems to be hindering a lot of ideas and will certainly decrease the demand on barrels and storage space.
Secondly lets dispel all notions that a tile can be abstracted into an acre, or a hundred square yards, or a hundred square feet. A tile is the amount of space a dwarf, a door, a barrel, a bed, or a table occupies. For the purposes of my arguement I assume its about the same as a DnD grid square, 5x5 feet. 25 square.
Being a bit of a farm boy, I can tell you in twenty-five square feet one grows roughly 12-18 corn plants, a figure which is varied based on soil quality. So the current yields aren't really high, they're actually low. Not all seeds germinating is also already in the game, since a peasant who gets one plant out of a tile put the same amount of seed in as a skilled planter who gets five plants out of the tile.
A six by six tile field is 30x30 or 900 square feet if we accept the 5x5 foot tile. Currently you can feed an entire fortress and then some without ever expanding beyond this scale. The field is a pretty sizable area to a dwarf, but not realistic. In reality, one acre of prime American farmland yields 160 bushels of corn (thanks to mechanized agriculture which we shall presume is 'legendary'), or 270 square feet per bushel (I'm fudging some decimals as this is not a scientific debate). In reality, this 6x6 plot of Legendary planted and fertilized land would amount to three bushels or 170 pounds of grain. If we assume the average dwarf has a slightly less hearty appetite than the average American, this amounts to some 42 days worth of food. Eating three pounds a day comes to 56 days worth of food. A full acre at this rate produces 8960 pounds of food, or enough to feed six dwarves for a year at near-American rates or eight dwarves at three pounds a day. If no changes are made regarding four-season, four-crop agriculture we can feed 32 dwarves a year with a legendary-planted, fertilized, productive-as-Iowa grain farm. The only problem is, assuming the 5x5 foot tile, this is a 42x42 field! It is almost the size of a 1x1 embark zone (48x48). Realism is not possible in the current simulation, unless almost the entire fortress is dedicated to agriculture (and legendary at it, too!)
With a goal of a somewhat realistic, if fun and gamey above-ground farming system, two points arise. The first is that crop yields must be higher than real life to allow a 200-dwarf fortress to endure on less than multiple embark tiles completely filled with farm plots. The second is that dwarves currently seem to eat very little and that nutrition is not a concern.
The problem of dwarven appetite raises three questions.
1. Does a dwarf satisfy hunger all at once? In Dwarf Companion hunger is tracked by a rather large, increasing value. That is, does a dwarf pick up a biscuit and eat it, returning to 0 hunger regardless of if he had 10,000 or 1,000 hunger?
2. Does a dwarf's food have a nutritonal value based on ingredients as well as a monentary value?
3. If meals did have hunger reduction based on nutritional value, how might that affect dwarven eating habits and consequencially, the demand for food crops?
At present I believe the first two questions are answered with 'no'. If that is true, then a fortress can sustain itself entirely on plump helmet spawn biscuits and wine, while another fortress might have the most elaborate *cow meat roast* banquets, complete with sides of dwarven cheese and *dwarven sugar biscuits*. Both fortresses' residents would still visit the dining room just as often. There is no incentive to create a varied diet, only an expensive one.
To find the answer to the third question, we must consider if each food had a nutritonal value as well as a monentary value. Dwarven sugar might be expensive but empty calories, while cave wheat flour is balanced as a happy medium and the basis of most meals. Meat and fish would both provide nutrient-rich substance to the diet. Dwarves could seek out food based on what their current needs were. Players would then have a strong incentive for crop rotations and importing overland foods that weren't local. Consumption patterns could also be altered. Dwarves might be inclined to pick up a sugar biscuit if they felt a bit peckish when they first woke up, stop for some vegetable stew halfway through their day, and have a good meat roast before going to bed. If dwarves required one medium grade 'stew' per month (which seems reasonable), we come up with three plants consumed a month on average or thirty six plants eaten a year, assuming they were all of nutrient-rich types. Assuming a one plant per tile yield, representing dabbling farmers and a poor harvest, this figures to one 6x6 plot to feed one dwarf for one year. In four seasons we have four dwarves fed. With skilled growers managing six plants 'surviving' per tile, we have 216 plants to harvest, feeding six dwarves. In four seasons, we have twenty-four dwarves fed. With legendary planters acheiving 12 plants per tile with all of the associated irrigation and fertilizing efforts, we have 432 plants feeding twelve dwarves. In four seasons, we have forty-eight dwarves fed; a quarter of a mature fortress. A 6x6 farm plot thusly becomes our new 'dwarven acre', feeding on average 24 dwarves assuming all plants are cooked into meals. Yields can be boosted by way of irrigation mechanics (an ajacent channel of water or brief flooding), fertilizers of various sorts, and any other methods added.
At this point four 'dwarven acres', planted by legendaries, irrigated and potashed, can feed an entire fortress requiring some 6,912 plants to be harvested and 2,304 *plump helmet stews* to be cooked. This can be done in a 12x12 area, or 3,600 square feet. But is this acceptable?
Consider: If booze is given no nutritional value, cooking booze effectively turns alcohol into a sauce rather than part of the dish and dwarves will be happier, but will not be as full. Dwarves will still demand ale, wine, rum and beer, meaning an extra field or two may be required to produce booze. Dwarves will still require fiber crops for the production of clothing. And most importantly, the current four-season agricultural system may well be up for changes.
For example, if the field now has its moisture level tracked it can easily occur that a summer dries out the field if the player fails to construct irrigation, or if the water source for irrigation itself dries up. This could lead to significant reductions in crop yield, or possibly wipe out an entire season. Freezing temperatures may also be tracked. Plants which can grow during a tropical winter might fail during a temperate one, likewise, summer may be the only plantable season in a freezing biome!
Above-ground farming thus becomes a matter of storing enough food to survive crop failures and seasonal changes, just as it was in 1400's Europe. Additionally, ambushing enemies may also spoil you crops while woodland critters simply eat the edges. Trampling fields could also ruin seedlings, making it wise to designate your fields low-traffic. With more imperfect agriculture, we may be looking at closer to eight or nine dwarven acres required to support a full fortress; a figure I am sure many players will find a suitable goal. Tending these fields would be labor intensive as we are looking at some 324 planting and harvesting jobs a season, or 1200 plantings and 1200 harvests a year to support 200 dwarves, each of which consume 48 plants a year (3 in a meal, 1 in a drink, twelve months a year). This comes out to a full-sized fortress consuming 9800 plants per year, requiring a yield of at least 8 plants per harvesting job.
If dwarves eat only once a season, divide all figures for crop yield and consumption by 4, however the labor demands for planting and harvesting remain the same. I believe if this general scheme were followed (modified, of course, but followed) we could well see livestock kept as 'famine reserves' and the fisherdwarf and butcher becoming a hero of society for their supply of high nutrient value ingredients. It will begin to make sense to trade with the caravans for food since your demand could well outstrip supply. Sieges which take control of your surface farming operations may well doom your fortress if sufficent reserves of longland grass flour aren't in a tightly-sealed iron vault for just such a contingency.
You might notice I never really touched on cave farming. Cave farming, in my opinion, should be a low-yield and almost subsistence level form of agriculture that you develop as an emergency food source against sieges or to provide some dietary variety. Fertilizers and flooding should all be required on a yearly basis to keep crop yields as high as four or six plants per tile. Assuming four plants per tile, a dwarven acre only feeds twelve dwarves per year, three or four of whom are in your food service industry to begin with. This is the reason for above ground farms to yield so much more; it allows developed agriculture to liberate the population to other pursuits; below-ground agriculture may well shackle them.
In any case, this post 'ran away' from me. I hope it adds to the debate.