The issue of Agri-Worlds

VicSage

Carpenter, Cobbler, Chirugeon, Dataminer.
One of the more common themes of Sci-Fi stories of all stripes is the addition of worlds dedicated to the production and processing of foodstuffs both for military use and export. Whether they arise naturally through commerce, or through some form of governmental decree, these worlds provide nutrition of varying quality to untold billions across their respective sectors. But it raises a very important question to me.

How long can they be sustained?

How long can this state last? If we were to use the Imperium of Man as an example, we've seen some last ~10,000 years. But during this entire process, the food being sent out is going to leach nutrients from the soil. Since it's being sent offworld, they won't be recycled naturally. Would this lead to the depletion of the soil over time? Would the constant export of millions of tons of foodstuff yearly lead to a leaching of carbon from the atmosphere, or would there be sufficient gain from volcanic or other sources to render that effectively moot?

I'm interested in your thoughts on sustainability of farming in either generic or specific settings. They allow for unheard of levels of centralization, the kind of thing you'd see in Caves of Steel or a hive world, but the loss of one of them due to simple overuse of the soil dooms multiple worlds to starvation.
 

PsihoKekec

Swashbuckling Accountant
It's a future fiction, we must simply assume there are some advances that made soil depletion thing of a past, so the problems we have don't concern them.
 

Bear Ribs

Well-known member
The most obvious answer is that agri-worlds are just continuous importers of... manure. That would solve both the mineral-loss issue of the agri-world, and the material build-up that must necessarily be occurring at the other end...
Yup. I can recall a couple of EU Star Wars stories that involved super-tankers full of excrement leaving Coruscant (and Jokes about how various types of excrement, both political and not, being its main export) and heading to agri-worlds to dump millions of tons of manure on them.
 

bintananth

behind a desk
I see Agri-worlds and pretty much any other single-industry world as the sign of a lazy writer. Planets are big and one populated enough to have large scale industry will be largely self-sufficient in terms of basic goods because space travel is neither cheap nor easy.

(Don't get me started on "teh dums" that are single-biome habitable planets with a breathable atmosphere.)

Foodstuffs are very bulky and cheap to produce compared to the other kinds of things you'd want to stuff into starship's cargo hold.

There will be some food exported off-world. It'll mostly be part of the regular supply runs to places which don't have sufficient local agriculture (nearby space stations, small outposts, new colonies, &c), expensive luxury items, or disaster relief.
 

Bear Ribs

Well-known member
In Space Opera planets basically substitute for "towns" in a normal fantasy epic. Thus you have backwater farming planet, trade hub planet, all-one-megalopolis planet, swamp planet, smuggling center planet, pirate-owned planet, etc. These would be farm villages, trade ports, The Capital, a pirate's den, etc. in a story set on one world.
 

Val the Moofia Boss

Well-known member
I see Agri-worlds and pretty much any other single-industry world as the sign of a lazy writer. Planets are big and one populated enough to have large scale industry will be largely self-sufficient in terms of basic goods because space travel is neither cheap nor easy.

It depends on the planetoid.

For example, Jupiter's moon, Titan, receives only 1% of the sunlight the Earth does, so using the surface area of the planet to grow crops would be a waste (also the gravity weak enough it can't keep an atmosphere anyway). Because Titan is cold and has a huge surface area, it can make for a great heatsink for a gargantuan manufacturing complex. You could turn Titan into a factory planet. Ofcourse, there would be food grown on or near Titan (probably in orbiting O'Neil cylinders and then exported down to the planet), but if you have a huge population of workers (even with automation, a factory planet is going to need a LOT of technicians and programmers and such), their food supply might need to be supplemented by other sources.

Agricultural worlds might also make sense if there is interstellar war going on. The agricultural worlds could provide the food required to sustain military campaigns, or if a planet's farmland is ravaged during a war (ie, glassed, nuclear winter, or a bio weapon came through, etc), then food could be sent to that planet to keep the populace from dying off. But this assumes that space travel is cheap.

In Space Opera planets basically substitute for "towns" in a normal fantasy epic. Thus you have backwater farming planet, trade hub planet, all-one-megalopolis planet, swamp planet, smuggling center planet, pirate-owned planet, etc. These would be farm villages, trade ports, The Capital, a pirate's den, etc. in a story set on one world.

Another reason is budget. Almost all of the worlds in Firefly and Stargate are backwater worlds that look suspiciously similar to some rural American or Canadian town is because that's what their location shooting could afford, and constantly trying to greenscreen huge CGI or miniature megalopolises would be too expensive. The only sci fi TV show that sometimes showed off huge megapolises with Star Trek TNG and DS9, using matte paintings, and even then there were only a handful of painting shots (San Francisco, Romulus, Qo'nos, Bajor, and Cardassia). And even then, the Star Trek matte painting shots didn't look as good as film budget matte painting shots like what Star Wars or Osris Chronicles did by cutting out parts of the glass to insert live action actors in to make the shot look more lively.

BP118pT.jpg

Osiris Chronicles Warlord of the Galaxy matte painting by Rocco Gioffre
 
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Bear Ribs

Well-known member
There's also a bit of a question in my mind on how fast and efficient interstellar transport is. The easier it is to ship stuff, the more sense an "agriculture" world makes since it would be cheaper and faster to just ship food one way and machinery the other. It makes no sense in BattleTech, notorious for its terrible economics anyway, for any planet not to be near-self-contained. It makes more sense in Star Wars where interstellar flights can be only a few hours long and there're ships that can carry millions of tons of cargo. If you can haul a couple billion tons a week with only one ship and low overhead, you're in a good place for worlds to hyperspecialize.

Additionally, it may be that worlds that can grow large amounts of foodstuff are simply rare. For instance presume that our solar system is typical, and there're 8-12 worlds and a couple hundred planet-sized moons that can't grow spit for every garden world like Earth. Logically you'd want to maximize Earth's massive food production capabilities and offload all your manufacturing onto the moons, Mars, or other locations that can operate a factory and all your mining on asteroids or metal-rich moons and planets so no industrial waste can damage Earth's food-growing abilities.
 

bintananth

behind a desk
a
It depends on the planetoid.

For example, Jupiter's moon, Titan, receives only 1% of the sunlight the Earth does, so using the surface area of the planet to grow crops would be a waste (also the gravity weak enough it can't keep an atmosphere anyway). Because Titan is cold and has a huge surface area, it can make for a great heatsink for a gargantuan manufacturing complex. You could turn Titan into a factory planet. Ofcourse, there would be food grown on or near Titan (probably in orbiting O'Neil cylinders and then exported down to the planet), but if you have a huge population of workers (even with automation, a factory planet is going to need a LOT of technicians and programmers and such), their food supply might need to be supplemented by other sources.
This applies pretty much everywhere that doesn't get enough light for photosynthesis or doesn't have an atmosphere:

Grow the crops on the surface in the great climate-controlled indoors. That way dealing with the hassle of climbing out of a gravity well and descending back into one just to stay fed is avoided. Plants also scrub CO2 and release O2 so that's one more thing the locals don't have to worry (as much) about.
 

Rhyse

Well-known member
a
This applies pretty much everywhere that doesn't get enough light for photosynthesis or doesn't have an atmosphere:

Grow the crops on the surface in the great climate-controlled indoors. That way dealing with the hassle of climbing out of a gravity well and descending back into one just to stay fed is avoided. Plants also scrub CO2 and release O2 so that's one more thing the locals don't have to worry (as much) about.
If you're extracting any real resources from a planet/asteroid/moon/spacejunk, then O2 is not an issue. Smelting enough steel to produce any given room will in turn release more oxygen than could ever reasonably fill that space. You're more than likely going to be dumping excess O2 off than needing more of it.
 

Marduk

Well-known member
Moderator
Staff Member
Agri-worlds make no sense as such if they don't use advanced agricultural technology and don't produce industrial quantities of food, so it would be obvious that the freighters that come to take the massive amount of food have a lot of free room coming there, unlikely to be filled with machinery and consumer goods for the planet's usually sparse population... leaving plenty of room for vast amounts of various fertilizers from the other planet's chemical processing plants. Overall a problem not much different from IRL food exports, moving vast amounts of material to different regions, even continents. This or some other chemical shortages in the soil may become a problem over hundreds or thousands of years, but its not a problem correct fertilizers can't fix, the details depending on the planet, its biosphere, and the plants being grown.

Another thing we already know about large scale, low cost optimized agriculture is that it can create incredibly cheap food already, and one would expect sci-fi civilizations to do it even better. So the agri-world question is, is it cheaper to make the food on an agri-world and pay for the cost of transporting it to wherever it is going, or to make the food, probably including building and running artificial production facilities to grow it in, wherever it would be going? In settings with massive space traffic, low population colonies needing food, or spaceships with cargo capacity measured in megatons, the answers can be quite surprising, and obviously dependent on the economics in the setting, if we even get such details and they are sensible enough in the first place.

Currently countries measure various food production and trade in MMT, aka million metric tons, aka megatons, so we already have some experience with that scale of food trade. You do need 40k scale ships to transport such amounts of food, perhaps even dozens or hundreds of trips per year to feed colonies of millions, but if you use these, the transport prices don't look that scary anymore, even if the cost of operating one such ship is is pretty high. If you have, say, a 4 MMT capable freighter, it would carry something around 2bn $ worth of grains at current prices.
Even if a round trip of that freighter costs staggering 500m $ in future space empire money, that still may be considerably cheaper than producing 4 MMT of grains in fully artificial ecosystems on a barren rocky planet with nice minerals, we're talking hydroponic domes with hundreds of square kilometers of growing area, the equivalent of a medium Earth city, which would need to be built, maintained, supplied and staffed with all the cost markups of being on a lifeless planet. At that price point it would have to beat 0.5$ per kg plus 0.125$ transport markup. Suddenly agri-worlds don't look so crazy at all. Unless the hydroponics can make the food with less than 25% markup over cost efficient, large area "classic" extensive farming.
And that's only bulk food of the cheapest kind, grains.
With pricier plants, or better yet, meats, or even better, foods already processed before transport, the transport markup would be an even lower proportion of the total cost of the imported food.
 
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The Whispering Monk

Well-known member
Osaul
I honestly don't see whole grain being exported at all. Do the processing on the agriworld so you have refined flours. Can get a whole new level of output, and it prevents any sort of refinery being necessary wherever the goods go. That opens up every market for your product. THEN you can offer the whole grains as a luxury good for even more money!
 

Ridli Scott

Well-known member
If I remember well in Bill, Galactic Hero this issue was covered in part. The capital world was an ecumenopolis whose export wasn't pencil-pushers or politicians but organic waste sent to the worlds where the food and oxygen were coming from. In this case, it was mature from organic waste and CO2.

I know this book is something like a parody and a comical view of the Sci-Fi but at the same time what the man in the waste disposal department was saying has a lot of sense if you want an ecumenopolis and an agri-world being possible.

Of course, if the transport chain suffers a problem the system could face a collapse, a catastrophic one.
 

The Whispering Monk

Well-known member
Osaul
If I remember well in Bill, Galactic Hero this issue was covered in part. The capital world was an ecumenopolis whose export wasn't pencil-pushers or politicians but organic waste sent to the worlds where the food and oxygen were coming from. In this case, it was mature from organic waste and CO2.

...

Of course, if the transport chain suffers a problem the system could face a collapse, a catastrophic one.

Thats why each ecumenopolis has a switch in their manure production centers.

The switch goes from manure to the production of Soylent Green. I mean...all them bodies gots to go somewhere.

😮
 

Hlaalu Agent

Nerevar going to let you down
Founder
Thats why each ecumenopolis has a switch in their manure production centers.

The switch goes from manure to the production of Soylent Green. I mean...all them bodies gots to go somewhere.

😮

So the final duty of all citizens is to go into the tanks? Chairman Yang would approve.

Though why couldn't they have rooftop gardens, vertical farms, windowsill planters, urban gardens (where you can actually have it), preserves, aqua culture/hydroponics combined in the waste proccessing system...
 

Marduk

Well-known member
Moderator
Staff Member
So the final duty of all citizens is to go into the tanks? Chairman Yang would approve.

Though why couldn't they have rooftop gardens, vertical farms, windowsill planters, urban gardens (where you can actually have it), preserves, aqua culture/hydroponics combined in the waste proccessing system...
They can... But food produced in such would be mighty expensive yet very small quantity compared to a city's needs, so who the hell would buy it. The real estate cost alone would make it expensive if we're talking cities. That's why so few bother with that kind of urban farming tricks IRL, and if they do, its to get fresh (not great quality btw) vegetables or show how green they are, rather than to provide any non-negligible portion of a city's food supply.
 

Bear Ribs

Well-known member
You also have to look at energy concerns. A major problem with IRL urban farming is how much grow-lights can add to the electric bill, it turns out it's surprisingly hard to compete with sunlight for cost.

Now maybe you're thinking "Oh, but they have superpower plants, energy won't be a problem, which is fair, but not the actual issue. It's heat. Every last joule you pump into the system will eventually turn into waste heat by hook or by crook. An ecumenopolis, just by virtue of the sheer number of human bodies giving off body heat, their lights, computers, air conditioning, etc. is already riding the ragged edge of physics for how much waste heat a planet can reasonably radiate away*. Adding in an entire agriplanet's worth of waste heat to grow lettuce makes the situation that much more ridiculous.

You can't cheat the laws of thermodynamics.


*Irregular Webcomic! #396
 

bintananth

behind a desk
They can... But food produced in such would be mighty expensive yet very small quantity compared to a city's needs, so who the hell would buy it. The real estate cost alone would make it expensive if we're talking cities. That's why so few bother with that kind of urban farming tricks IRL, and if they do, its to get fresh (not great quality btw) vegetables or show how green they are, rather than to provide any non-negligible portion of a city's food supply.
If they aren't doing it for the fresh vegetables or bragging rights they could just be into gardening as a hobby.

Fr'ex: my mom's garden includes potatoes, tomatoes, rhubarb, mint, and several spices. She likes the way the plants look. The plants being more than decorative is an added bonus.
 
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