Mishnah Niddah 6:5: Any [food] that requires tithing can be rendered impure with the impurity of foods. But there may be [food] that can be rendered impure with the impurity of foods but which does not require tithing.

כֹּל שֶׁחַיָּב בַּמַּעַשְׂרוֹת, מִטַּמֵּא טֻמְאַת אֳכָלִים. וְיֵשׁ שֶׁמִּטַּמֵּא טֻמְאַת אֳכָלִין וְאֵינוֹ חַיָּב בַּמַּעַשְׂרוֹת:

Mishnah Niddah 6:6: Any [crop] that requires pe'ah [the requirement to leave, when harvesting, a corner of the field for the poor] requires tithing. But there may be [a crop] that require tithing but which does not require pe'ah.

כֹּל שֶׁחַיָּב בַּפֵּאָה, חַיָּב בַּמַּעַשְׂרוֹת. וְיֵשׁ שֶׁחַיָּב בַּמַּעַשְׂרוֹת וְאֵינוֹ חַיָּב בַּפֵּאָה: