Maaser Sheni 5:1 - 5:2

כרם רבעי מציינין אותו – they build near it a heap of stones and a sign so that they will recognize that it is fourth-year grapes.

בקוזזות – a heap of stones and/or clods of earth; a sign like the ground. Just as the ground which one derives benefit from and makes produce, even this also, when it is redeemed, it is permitted to derive benefit from it.

ושל ערלה בחרסית – in the ground when one makes from it an earthenware utensil. Its sign is like this burned-clay that one does not derive any benefit from it when one seeds it, one does not remove it in order to have a quantity of seed required for a field (see Mishnah Peah, Chapter 5, Mishnah 1), even this, there is no benefit from it.

ושל קברות – so that a Kohen nor a Nazirite will not enter into there.

בסיד – A sign that the white plaster is like bones.

וממחה ושופך – dilute the plaster/lime in water so that it will become more glossy white and then it is poured upon the grave.

במה דברים אמורים – that they make a sign for fourth-year grapes and fruits of a tree during its first three years.

בשביעית – where everything is ownerless and people can take with permissions. But in the rest of the years of seven-year cycle, when they come to steal, they stuff the produce into the mouth of the wicked person so that he will glut it and die (See Talmud Bava Kamma 69a) and they will take it to eat while it is forbidden.

והצנועים – those who are exacting upon themselves, when they had fourth-year grapes during the seventh year, they would set aside the monies prior to harvesting and say: All that is harvested, when it will be harvest, will be redeemed on this.

כרם רבעי – it has the same law as that of Second Tithe, and one must bring the fruits up to Jerusalem and consume them there, either them or their redeemed monetary value, and the Sages ordained that a walk of [one] day all around Jerusalem they would bring up their fruits [themselves] in order to adorn the markets of Jerusalem with fruit, and since every person would consume the fourth year’s fruits of a young tree, the mark would become full of the rest of the fruits.

שיהא נפדה סמוך לחומה – even the vineyard that is near the wall.

שאימתי שירצו – if the fruit would be diminished

משחרב בית המקדש היה התנאי – not because the fruits increased, as has been said, but rather since the Temple was destroyed and Jerusalem came into the hands of the enemies, and they would not suspect to adorn the markets of Jerusalem with fruits.