Leviticus 23:22 "Nor shall you gather any gleanings of your harvest..., you shall leave them to the poor and to the stranger"

Another way for the farmer to provide the poor people with their share in the field is to leave fallen stalks.

As the produce is reaped, individual stalks often fall to the ground.

The Torah commands us to leave them on the ground so the poor can collect them afterwards (see Negative Mitzvah 211).