I understand that, but China is still industrializing and has an enormous abundance of labor. They have over 425 million farmers (and a decade ago, that number was 700 million). At achievable efficiency, that could easily be done by as few as 50 to 100 million, but then there just wouldn't be any available jobs for the other 300+ million people. China is already using workers in massive unneeded building projects and has an army of over 2 million soldiers and who knows what else, just to keep the unemployment down.

A higher produce efficiency is not only not needed, it is unwanted. Full labor market participation is of much more value to the Chinese right now than the efficiency of the produce industry.