נחמיה י:לב פירוש: רש״י

and all grains Heb. שֶּׁבֶר, grain, like (Gen. 47:14): “... for the grain (בַּשֶּׁבֶר) that they were purchasing.”

or on holy days This refers to festivals.

and we shall abandon during the seventh year As is stated (Exod. 23:11): “But throughout the seventh year you shall let it go and abandon it (וּנְטַשְּׁתָּה).”