Knurlkyth
Crunch
Knurlkyth is an older Dwarven city dating back before the fall of the High Elves. While rich in many metals and minerals It was not founded in the pursuit of underground resources. It instead began its life as a training ground where Dwarves and Twilight Elves developed the foundations of several martial traditions.
A well developed network of aqueducts and tunnels brings water from several sources higher qin the mountains. These feed into the six cooling shafts that largely surround the subterranean parts of the city. A percentage of the water flowing into the city is used to power the machinery that makes the residents lives easier, a central shaft houses elevators that move ore and rubble up from the depths. A second more isolated shaft draws the more pungent waste up from the city to an area of tunnels and rooms near the surface where this and other waste is processed.
High gate (terraced farms)
The waste and heated water are then used in the terraces which densely line the parts of the mountain valleys that collect the most sunshine. Grain crops cover these terraces more densely than they do on the human fields at lower elevations. About a third of the area around the high gate is under intense cultivation.
Amaranth, due to the small size of the seed amaranth does not benefit from the use of an early seed drill. For every pound of amaranth grain produced six pounds of material is collected for fungus production with another three pounds consumed by animals or used for other purposes. Another crop is grown in the more marginal areas around the high gate is miscanthus (a.k.a Silver grass or Elephant grass) Producing around eight tonnes of carbon rich material per acre miscanthus is used where wood would normally be used in places below the tree line. This is a grass that can grow to about 10 feet in height. This provides a sulphur free fuel source close to where its needed, coal would be used in areas where sulphur isn't an issue.
While the majority of the fields grow the amaranth equivalent some areas are rested in an irregular fashion and used to grow peas, greens and root crops. In terms of grain production the intensive dwarven terraced system produces forty percent as much per planted acre as more traditional wheat at lower altitudes. Without the necessity of crop rotation the land the dwarves can put under plow (roughly 1/3rd) is comparable in grain production, if not total actual food production to human farms at lower altitudes.
In general the produce from the area around the High gate is low in carbohydrates. To partially overcome this the animals farmed in the area would be bred and raised for a higher fat content. The animal fat would also be of use in the production of metal and leather items.
An area approximately 20 by 5 miles is farmed in this manner with animals being herded around the higher pastures surrounding the area as conditions permit. This results in about 20000 acres for food production. Unseasonal storms are a constant risk. This produces 4500 tons of grain
Middle gate (field)
This is a mix of more typical farming methods revolving around a typical three field or (scandinavian/northern european) four field system and the terraced system the dwarves use at higher altitudes. The techniques from higher altitudes are also used here, though they are used less intensely. For example the terraced fields could be as narrow as three or four meters near the high gate while near the middle gate they may be twenty or thirty meters wide. Many other cereal crops are possible at this altitude, presuming dwarven dietary requirements are similar to human ones carbohydrate rich crops will be important. The rubble generated by the city is also used to make higher quality roads than are normally encountered. Irrigation is well developed. Defensive structures such as retaining walls are incorporated with the agricultural infrastructure. (There is less incentive to have these defenses higher up because armies from low altitudes are put off when they start coughing up their lungs)
An area twice the size of the high gate system is cultivated. Oats, barley and pasture account for most of the land area though other crops are grown in rotation. The intense infrastructure allow the selected crops to be grown slightly better than a comparable human farming community at lower altitude. (15-20%). This is the result of the many years of work that has been put into the originally poor area.
Lower gate
This entrance houses a small community of dwarves who both trade dwarven products and provide the city with wood and timber. They source the wood from the forest surrounding the river near the entrance. This is taken by water to a system of locks inside the lower gate that lift the wood to the mills within the city itself. Not much is grown around the lower gates due to the semi-regular flooding, this leaves visitors with the impression that the dwarves have no surface agriculture.
High altitude forestry
Timber of a very high quality is produced slowly at several locations around the high and middle gates. This is an irrigated forest that grows at least half as fast as it would if it was at lower altitude. The wood produced is 10-30%
stronger and denser however.
Farming within the mountain
The resources harvested from around the high gate allow for up to 24000 tonnes of fungus to be produced. Assuming half of this is used for lightning and medicine this leaves 12000 tonnes for consumption. 2000 tonnes is used for puffball flour production resulting in 120 tonnes of flour additive. 2000 tonnes are probably wasted or fed to “storage” animals. This leaves 8000 tonnes for food, however assuming a dietary maximum of 40% fungal sources each dwarf consumes not much more that 300 lbs per annum. As a result production capacity isn't the restricting factor here, maximum consumption is. They can easily grow more fungi than they need.
Depending on the exact mycocultural requirements raw materials (wood and hay/straw) are brought into the mountain where they are either pasteurized with boiling water or used as animal bedding in shallow well ventilated cave/shed systems. This enriches the material with nitrogen and begins the decomposition process, the material is then heated to sterilize it before the spores from the desired fungi are added. Once the mushroom crop is harvested the growing medium is composted and added back into the soil. It is also easy to stockpile the growing medium in dry form for sieges and other similar locked in situations.
Heating the growing medium before the spores are added may use recycled heat from any smelters and forges if there is sufficient energy remaining to carry the smoke and fumes out of the city. A very deep borehole might also serve as a source of extremely hot water. Alternately firewood or dried miscanthus could be used as a heat source. Coal could be utilized but care must be taken to keep the smoke and residue separate from the fungi.
Animals
The High Gate terraces produce little in the way of carbohydrates, this means animal production will be limited. Sheep, goats and cattle can be grazed on pasture and forested areas around the city. They are brought inside for short periods of time in the depths of winter when even the pastures at comparatively low altitudes are snowed under. Poultry are found in the very few farming villages on the surface. This is due to a lack of light reducing the laying capability. The manure from this birds is very useful for mycoculture however. Pigs (or other omnivores) are kept near the living areas of the dwarves where they are used as both a food storage system and a means of recycling waste food. Fungi fodder crops are grown for them but they need a more varied diet than mushrooms alone. (The fungi are basically used to bulk out their diet)
Switches
Aquaculture
The need to provide carbohydrates for omnivorous species such as tilapia means they are not an attractive option for inside the cooling boreholes. However species like Grass Carp would likely do well in the existing irrigation system. Without special attention they might add up to five percent to the food output of the terraced system. If fields are flooded to allow them to eat the weeds and remnants of (primarily) pea and other crops larger numbers could be supported. This would require crops to be planted as fish food for other parts of the year. Some hybrid systems with fish in rice paddies add 30% to the total food output.
Mining for fertilizer
It is possible that the dwarves with their focus on minerals may develop the knowledge of basic mineral fertilizers. If so yields may be up by 20%. The biggest change this would make is how fast a section of poor mountain soil could be turned into a fertile field.
Insects
Another possibility is using insects to turn waste plant and fungal material into protein and fat for carnivorous or omnivorous animals, this would allow for subterranean aquaculture, larger pork production and increased poultry numbers.
Depending on the setting this agricultural systems would support a secretive dwarven population of 5-10,000, a self sufficient population of 10,000-20,000 or a thriving population of 25,000+ who trade for food with other groups.