Ladies and gentleman, today we were summoned by the Agro-nerd council with one unique mission: we must take a single acre of land and feed the largest amount of people possible. But this isn't your average "how many people can be fed in a square kilometer?" question, because today we are following the example of the Chinese!
In his excellent work, Farmers of Forty Centuries, Franklin Hiram King recorded some farms in the Shantung province where a family of ten was (barely) fed by a mere 1.66 acres. In other words, 6 people were sustained in a single acre, and we must remember that, according to King, Shantung was far from being the most productive region in china (that being the pearl and yangtze deltas), and even was facing an extended drought!
The Chinese achieved this extreme yields thanks to diligent and intensive work on their objectively small farms: a single plot was seeded and harvested THREE times a year, and far from being depleted, that same plot remained productive for centuries without a single inch left fallow thanks to an almost religious diligence towards fertilization: from night soils to ashes and scraps, everything was returned to the land. With the help of polyculture the Chinese farmer integrated poultry and fish inside their irrigation canals and used every inch of land and water available.
But today, gentleman, we have the whole modern world and it's green revolution at our disposal: you can use everything technology and science has to offer. From modern pesticides and fertilizer, to GMO fast-growing yield-increasing crops supercharged with C4 photosynthesis. You can pick the most fertile soils in the most fruitful climate and blessed with the best irrigation canals in the world. Just remember: the soil must be worked. You cannot postulate Heresies like "hydroponics" or "aeroponics", least the wrath of the council destroys our world.
So, my dear friends, please help me feed the world!