回复：中国人勒紧裤腰带的毛泽东时代

The bio technology ,  Rice   hybrid technique  for    High yield rice  produce  start at Mao time,  plus industrial produce  nitro fertilizer, and better irrigation system and  more electric machine for farmer.
  Lot of  good things start at Mao time,  people like see results, but not realize it is difficulty at beginning.