There’s an opportunity for innovation, here - if you could optimize production of Soylent ingredients on a massive scale, somehow made it completely acceptable to all segments of the population, and obtained the right facilities and technology to process the ingredients, you could rocket Soylent production into an entirely new economic universe. That means no gmo, no pesticide, closed loop fertilizing (no runoff, everything is cycled back in,) solar powered facilities, etc.
The biggest challenge as I see it is to make it economically viable to grow. I think the bottleneck is going to be the ingredient sources, as those directly affect economies of scale. It won’t matter how popular it gets if the supply can’t match demand, because enthusiasm will wane.
One bushel of oats is 32 lbs, or 14,500 grams. Official Soylent has 110g oat powder per day, meaning that to get a years worth of oats for one person, you need 2.8 bushels. An acre of land can produce 100 bushels of oats, so to get just 2.8 bushels, you’d need 114 square meters, or to round up a bit, a lot 11 meters on each side.
For corn maltodextrin, you need to hydrolize the starch from corn - about 70% of the kernel by weight. Assuming 70% of your yield goes toward maltodextrin…
52 lbs of 15.5% moisture corn per bushel. 150 bushels per acre. Dry it out, leaving 30 lbs corn endosperm (starch) per bushel, giving you 4500 pounds or about 2000 kg of maltodextrin. Since you need 165 grams of maltodextrin per day, that means 6.0225 kg per year. That comes out to 12 square meters, or a lot 3.5 meters on the side, for one person’s worth of maltodextrin per year.
Brown rice yields about 7000 lbs per acre. 102 grams of rice protein is needed per day . Rice has a complete protein profile, and yields around 8% of its weight as protein. 37230 grams of protein are needed per year, or 465375 total grams of rice, or 1026 pounds. This takes up about 610 square meters, or a field 24 meters on each side.
Canola yields about 40% of its weight as oil. There are 30 bushels per acre, 50 lbs per bushel. An acre yields 600 lbs of oil per year. You need 56g of oil per day, so around 46 lbs or oil per year. That takes up 307 square meters, or a field 18 meters on each side.
For the macronutrients, as they stand, for each person, a years worth of each (assuming only one harvest) takes up 1043 square meters, or roughly 1/5 of a full size football field.
Assuming 1043 square meters per person, for Soylent to feed 300,000 people, you’d need a farm that was 31,290,000 square meters, or ~5600 meters on each side. 7732 acres. That’s about 3.5miles on each side, for us Americans.
If you were going to feed the entire world (assuming 8 billion people,) then you’d need 206,189,244 acres, or a field roughly 570 miles to each side. That’s just over half the state of Nebraska.
If you take into account multiple harvests, space optimizations, change the recipe to incorporate rice starches and corn protein, I’d bet the overall size for one person could be cut down to a 900 square meter field, 30 meters on a side. Maybe a lot smaller if you get multiple harvests.
If you had a hypothetical nuclear powered mega-farm that used electric grow lights, you could stack the crops on top of each-other, cutting the footprint significantly (how’s that for dystopian!)
I’ve rounded up in these estimates, and used google liberally. My numbers might be very high or very low, as I went with the first link of the first page of results that seemed plausible. I personally think that you could get the size down to half of what I’ve presented here, but don’t currently have the time or inclination to justify it .