L4 Settlement - Farm Cylinder

The farm cylinder is a second cylinder attached to one end of the settlment cylinder of same construction with an outer 2504m cylinder and in inner 2500m circumradius dodecagon. I would increase the thickness of the carbon fiber exterior layer to improve the strength as the mass for this part of the cylinder will likely exceed the 25kg/m2 average that is found within the settlement.

I did quite a bit of research to determine what would be the makeup of the farm cylinder. The way I planned it, probably not the most efficient, but it does allow for the farm cylinder farms to grow as the population grows. I determined the yield of an aquaponics setup growing lettuce and tilapia, a livestock farm with goats and chickens for milk, cheese and eggs, inground crops like corn, potatoes and carrots, a big raised bed aquatic system to grow rice and an orchard of nut trees. Put all of that together and call it one farm.

I found that pasture raised eggs could produce 296400 eggs per year for a hectare (10,000m2) with 988 hens. I found that goats (17 of them) could produce 16065kg of goat milk per year per hectare. For corn, potatoes and carrots, each on half a hectare, producing 6276kg, 16500kg and 2500kg per year respectively. One hectare of rice provides 4000kg per year. Within a 2000m2 area 20 aquaponic setups would altogether produce 640kg of tilapia and 3600kg of lettuce. 3 hectares of orchard, though some of the orchard could share the chicken and goat area produces 11,000kg of nuts (almonds, pecans and walnuts) per year.

So one farm occupies 77000m2 and produces 83081kg food / year plus 24700 dozen eggs.

I found that a fair average for human consumption of food by kg was 715kg/year and so given how much food a single farm produces, for a total settlement population of half a million people, 4313 of these farms are needed. To fit that many farms in the farm cylinder I had to make the farm four levels and extend from my originally planned 5km length of 2500m circumradius dodecagon to 5150m length. I allowed for 4m of height between levels, and in this configuration all of the orchards for all of the farms would be taken out of the farms of levels 1,2 and 3 to reduce the footprint of those farms so as to give the nut trees a higher growing area on the top level.

For each farm we would need certain personnel:

For the 20 aquaponics setups it would take a lot of work and effort to get them setup and started, but once started it could be 3FTE (full time equivalent) that manages it. Tasks would include feeding the fish and doing all sorts of monitoring of all of the plants and the various levels of ammonia, nitrates, nitrites, oxygen, ph and other aspects of the water passing through each of the 20 setups of the farm. One person could work from 7am to 2pm and another could work from 1pm to 8pm so that they have one hour of overlap to discuss everything aquaponic. With three people they could split up their time however they want with respect to weekends. Tasks would include planting/harvesting the plants and fish and bringing them to the food processing building.

For the livestock I also figure 2FTE to feed and care for the animals, to get the milk and eggs and to clean up as needed. Tasks include feeding the animals, retrieving and cleaning the eggs and bringing the eggs to the food processing building in reusable egg-dozen containers. Getting the milk from any goats that are lactating and delivering the milk to the food processing building. Calling a farm vet if one is needed.

For the corn, potatoes, carrots and rice, I figure 4FTE, one for each of these, however, many many more at times of planting and harvesting. In this case we would try to stagger all of the farms on a level to have their planting and harvesting on different days so that a planting team can be created that moves from farm to farm, and a harvesting team is created that moves from farm to farm. It could be one person responsible for each of the corn, potatoes, carrots and rice such that each person becomes or is already total expert at everything there is to know about growing their specific food. It could be that during the growing season these workers do not need to spend a lot of time at their respective farm; especially if we get an automatic watering system in place. However, on planting and harvesting days they will need to be there to direct all of the casual workers (and of course to do the work themselves).

So there would be 9FTE who are the permanent farm workers who would be assigned to work at one specific farm. They could all help each other at specific times when more help is needed.

9FTE for 4313 total farms means we would need 38814 permanent farm workers.

The casual farm workers that have been described in previous posts would be anyone who isn't a farm worker who is expected to do about 3 hours per week in the farm. These people would work on the planting and harvesting teams that move from farm to farm and simply need to follow the permanent farmer's instructions.

These farm components will need all sorts of inputs, hopefully we can source many of them from the farm itself.

Fish food pellets - I have found some recipes online that make it appear that what we grow can almost fully be processed using potato starch as a binder. If there is any component that is critical for the fish that we can't produce, we will import it from Earth.

Aquaponic minerals and ph controllers - these would need to be sourced from Earth on a continuous basis until we find a way to produce these or manage them ourselves. Aquaponic growing medium would be something we would need to import from Earth until all 4313 farms are built, and then maybe we can find a way to recycle the growing medium with just occasional imports from Earth.

Herbicides and pesticides ought to not be needed so long as we do not allow for weeds or plant diseases to show up in our farms. Fertilizers on the other hand may be needed. A potassium, nitrogen and phosphorus compound, or Potassium nitrate; these are also things that we would need to get from Earth unless we could find a way to produce it.

I am assuming the chickens, goats and fish will all find ways to reproduce once we get the initial imports from Earth, but we'll need the permanent farm workers to manage that. This may include euthanising the male chicken chicks at hatching, culling the non egg laying hens, culling the aged out goats, but making use of all of these things perhaps for some for fish food, some for human consumption and some for composting.

In terms of the construction, each farm on each level will be setup on half of one side of the dodecagon so that it is entirely flat. So two farms would be back to back of a depth from the dodecagon vertice to the center of the side by 647m, and lengthwards into the 5150m direction by 114m. Between them at the center of the edge will be a narrow path that has a waist high rollor track that goes the length of the farm cylinder so that all of the farms that back on to this center of dodecagon edge can use the rollor track to walk with/push the universal bin that is used for the purposes of transporting harvest(s) to the food processing building.

The food processing building will span all four levels but will occupy only one side of the dodecagon, so those roller tracks that are on each of the other 11 sides will need to then turn left or right to follow a circumradius track that leads to the food processing building that is at the settlement end of the farm cylinder.

The processing building on levels 2, 3 and 4 would just be to finagle a way to roll those harvest bins down to level 1 and to roll or lift up those bins now empty back to the upper levels. Level 1 and part of the sub-level is where all of the food processing is going to happen. 

Examples of what the food processing building could have people do:

Take the lettuce, kale, bok choi, strawberries and anything that was harvested aquaponically and is to be delivered raw and put them directly into a bin destined for an apartment complex.

Taking the egg dozen containers, putting two or three into an export bin.

Process the goat milk into goat cheese and then package both the milk and the cheese into reusable containers and put an appropriate amount into an export bin.

The farm workers will do a cursory cleaning of the potatoes, carrots and corn, the food processors will do a final cleaning of these items and then distribute them into the export bins.

The fish would be prepared in a certain way for ease of cooking for the apartment complex kitchen crew, packaged in a reusable container and then put into an export bin.

Take whatever is needed to make the fish food pellets, make the fish food pellets, and put that into bins that go back out to the farms.

My original idea was to have people riding cargo bikes in the sub-level to deliver the food bins to the apartment complexes, but with 3333 apartment complexes and some of them over 10km away I came up with a different way. Though there are already numerous things (water supply, waste water, electricity, HVAC) attached to the ceiling of the sublevel, there ought still to be room to have a conveyor and roller track system with numerous switches that lead both to and from every apartment complex' kitchen. There would be a slot on the front side of a food bin that gets put into it a card with the apartment complex number in a big and clear UPC code. Scanners distributed throughout the network of conveyors and roller tracks will scan the UPC and set the conveyor switches correctly to guide the bin to that apartment complex. On the back side of the bin is the 'home' UPC that is fixed, so the kitchen person would empty the bin in the kitchen and then put it back in the floor, now with the bin facing the direction that scanners would guide it 'home' - back to the food processing building. This is why the food processing building in the farm cylinder drops into the sub-level though most of the work is being done on level 1, it is so that the bins can be moved into this sub-level conveyor and roller track system to get to its destination.

My last thought about all of this is that some of the things that grow may need proper seasonality while others may need diunural/nocturnal changes and still others would be happy with the same temperature, insolation and humidity perpetually. If this is the case, we would need to break apart some of the foods from all the individual farms to have those specific items grown in an environment that is created specifically to suit their growing needs. All of the assumptions I made above in terms of farm space would still hold; for example the space for rice could be removed from all of the individual farms which then opens up a space where a new hot sunny (artificial sun) place is created where only rice grows.