Beis Shammai say: [Produce declared] ownerless for the poor is ownerless. But Beis Hillel say: It is not ownerless unless it is declared ownerless also for the rich as with Shemittah.  [If] all the sheaves of the field are each of one kav, and one is of four kavs, and he forgot that [one] —- Beis Shammai say: It is not shich'chah; but Beis Hillel say: It is shich'chah.