1) A "KINYAN CHAZAKAH" ON A FIELD
QUESTION: Rav Zevid rules that when two people acquire a field full of trees by performing an act of Chazakah, with an agreement that one acquires the trees and one acquires the land, the one who acquires the trees receives only trees, and the one who acquires the land receives all of the land. The RASHBAM explains that the Chazakah referred to in this case is not a "Chezkas Shalosh Shanim," where each person uses the trees or the land for three years, but rather it refers to a "Kinyan Chazakah," an act of Kinyan on the land, such as pruning the trees and plowing the land.
TOSFOS (DH Zeh) asks that according to the Rashbam, since the Chazakah in this case is not that of "Chezkas Shalosh Shanim" (which serves only as a proof for a Kinyan), but rather a Chazakah which itself is an act of Kinyan, why does the Gemara need to say that the two people made a Chazakah at all? The Gemara could mention any type of Kinyan that two people make on a field, such as a purchase with money or with a Shtar!
ANSWER: The KETZOS HA'CHOSHEN (216:2) answers by citing the opinion of the MISHNEH L'MELECH (Hilchos Mechirah 1:8). The Mishneh l'Melech rules that when a landlord rents out his house and then decides to sell the house, the sale cannot be done through a Chazakah-type of Kinyan, such as by locking the doors. Since the tenant, at the moment, has the right to use the house, it is not possible for someone else to perform a Kinyan Chazakah on the house, because such an act is a demonstration of his sole ownership, but he cannot show his sole ownership when someone else is using the house.
The Ketzos ha'Choshen explains that according to the ruling of the Mishneh l'Melech, the Tosfos' question on the Rashbam is answered. In the case of two people who acquire a field together, where one person acquires the trees and the other acquires the land, the Gemara can discuss only a Kinyan Chazakah and not any other form of Kinyan, for the following reason. Rav Papa asked Rav Zevid that if the tree-owner has no rights in the land, then why can the landowner not force him to remove his trees? This question is based on the fact that Rav Zevid maintains that the tree-owner has absolutely no rights in the land at all. This premise is evident from the fact that the landowner was able to make a Kinyan Chazakah on the land. If the tree-owner would have owned some share of the land, then the landowner would not have been able to acquire the land with a Kinyan Chazakah, since such a Kinyan can be made only where no one else has rights to the field. From the fact that the landowner is able to make a Kinyan Chazakah on the field, Rav Papa proves that the tree-owner has no rights to the field. This is why the Gemara must be discussing a case of a Kinyan Chazakah and not any other form of Kinyan, for otherwise Rav Papa would have no proof that the tree-owner has no rights to the field. (Y. MARCUS)
2) HOW CLOSE TO A SINGLE VINE MAY ONE PLANT GRAIN OR VEGETABLES?
OPINIONS: The Gemara quotes the Mishnah in Kil'ayim (5:2) in which Rebbi Shimon states that a vineyard that takes up less than four Amos of space does not have the status of a vineyard because the plants are too close to each other and thus cannot grow properly.
(a) TOSFOS (DH Eino) explains that since such a formation is not considered a vineyard but rather an isolated vine, one who wants to plant grain or vegetable seeds near the vines does not need to distance them four Amos from the vines in order to avoid transgressing the Isur d'Oraisa of Kil'ayim. Rather, it suffices to distance them three Tefachim.
The RASHASH (82b) points out that in two other places in Bava Basra, Tosfos also mentions that it suffices to distance seeds three Tefachim from a single vine (19a, DH ha'Mavrich, and 82b, DH v'Zore'a). This is the opinion of Rebbi Akiva in the Mishnah in Kil'ayim (6:1). The Tana Kama there, however, maintains that one must plant the seeds at least six Tefachim away from a single vine. Tosfos rules like Rebbi Akiva (even though the Halachah normally follows the majority opinion) because the Yerushalmi rules like Rebbi Akiva in this particular case.
(b) The RAMBAM (Hilchos Kil'ayim 7:1) maintains that one must leave a space of six Tefachim, in accordance with the view of the Tana Kama.
The PORAS YOSEF (17b) suggests that perhaps Tosfos rules like Rebbi Akiva only for places outside of Eretz Yisrael, based on the statement of the Gemara in Berachos (36a) which says that in any dispute regarding agricultural Halachos, the Halachah outside of Eretz Yisrael always follows the lenient opinion. Accordingly, Tosfos would agree with the Rambam that in Eretz Yisrael one must leave a distance of six Tefachim between the seeds and the single vine. (Y. MARCUS)