Ketubot, Chapter Eight, Mishnah Four
Rabbi Shimon teaches a general rule to help govern what belongs to the husband and what belongs to the wife.
1) Rabbi Shimon says: In respect to that in which the husband is at an advantage when he marries his wife he is at a disadvantage when he divorces her and in respect to that in which he is at a disadvantage when he marries her he is at an advantage when he divorces her.
a) Produce which is attached to the ground is the husbands when he marries his wife and hers when he divorces her,
b) Produce that is detached from the ground is hers when she marries but the husbands when she is divorced.
In this mishnah Rabbi Shimon teaches a simple way of remembering which produce belongs to the husband and which produce belongs to the wife during marriage and after its dissolution. When the marriage begins, and as part of her dowry she brings a field that has on it produce attached to the ground, that produce is considered to be like produce grown after the marriage, and it belongs to him. This is the opinion of the Sages in the previous mishnah. When the marriage is dissolved through death or divorce the produce attached to the ground remains the property of the woman, as does the ground itself. In an opposite direction, produce which is detached from the ground is hers when she is married. If she brings this as part of her dowry, then it is used to buy land, as we learned above. However, at the time of divorce, detached produce already belongs to the husband and he need not return it to his wife.