As title says, but for added context, here goes: The setting is a rather intricate take on hard-magic meets science-fiction, and takes place in a highly advanced milky way populated mostly by humans and other vaguely-humanlike aliens that share most, if not all the same physiological nutritional needs – That being, Carbohydrates, Fats, Proteins, Vitamins, Minerals and Water. Due to the exponential growth of population accelerated by relatively cheap hyperspace travel, discovery of several habitable exoplanets, and ease of construction of massive space structures that can support over a billion inhabitants with ease, I find that food production might be a bottleneck, and something hard to explain in this setting, as the overall population will cross the dozens of trillions – Though, water and minerals would not be concerns, as offworld mining operations would generate more than enough leftover for any purposes, and, with enough technology, all water is indefinitely reusable.
That being said, I want to know if a highly technologically advanced earth be would capable of providing sufficient nutrition for all those trillions of inhabitants, and through which means would that be possible – And, if it is not possible, which I highly suspect it’s not, what would be the ideal conditions, climate, atmosphere, substrate composition, and crop choice on an exoplanet or exomoon dedicated exclusively to farming: a Farm-world? Would a single planet suffice, or would multiple smaller planets be necessary and/or more efficient for that purpose? What advantages an exomoon has over an exoplanet, if any?
After some study, I found that planets with very dense, carbon-dioxide rich atmospheres, that are also closer to their star would benefit greatly due to boosted photosynthesis and metabolism – However, a planet with those traits would also be victim to a runaway greenhouse effect, killing everything on it.
Workers are NOT to be considered – any and all workforce needed can be easily provided by machines, humans need not apply. Likewise, power and electrical needs are not issues, as solar and fusion technology is in surplus, and energy can be beamed from orbit if necessary. Interplanetary and Interstellar logistics are also facilitated by Alcubierre and Hyperspace drives, but getting to and from orbit might remain difficult – With that in mind, we can focus only on the matter at hands, which is what would be the ideal conditions for accelerated crop growth on a farm-world.