As Piaas said, the maximum number of berries per chunk is 16. Pressing the key F3 + G can be used to display chunk boundaries. If you have more questions, please feel free to let us know!
Great question! The main reason why we have a berry/apricot limit is to avoid excessive lag build-up. You can still build Pokeball farms by placing the berries/apricots along the sides of the chunks and run an extensive line with a two-block width(you may see these made by other players in the world).