《天工开物·上篇·粹精》
但是留着当稻种的稻谷，恐怕被磨掉保护谷胚的壳尖而使种子发芽率减弱，因此南方种植水稻较多的人家，大部分稻谷都是用牛力脱粒，但是留为种子的稻谷就宁可在石板上摔打脱粒。
但作种之谷，恐磨去壳尖，减削生机。故南方多种之家，场禾多藉牛力，而来年作种者则宁向石板击取也。
However, rice grains kept for seed may have the protective shell of the germ removed and thus reduce the seed germination rate. Therefore, most families in the south who grow rice use oxen to thresh the rice, but the rice kept for seed is threshed on a stone slab.