Jerusalem Talmud Sheviit 1:4

משנה: שְׁלֹשָׁה אִילָנוֹת שֶׁל שְׁלֹשָׁה אֲנָשִׁים הֲרֵי אֵלּוּ מִצְטָֽרְפִין וְחוֹרְשִׁין כָּל־בֵּית סְאָה בִשְׁבִילָן. וְכַמָּה יְהֵא בֵּינֵיהֶן רַבָּן שִׁמְעוֹן בֶּן גַּמְלִיאֵל אוֹמֵר כְּדֵי שֶׁיְּהֵא הַבָּקָר עוֹבֵר בְּכֵלָיו. MISHNAH: Three trees belonging to three different owners are counted together and one may plough the entire bet seah for them. How much space must be between them? Rabban Simeon ben Gamliel says, so that the ox and its harness can pass⁴²Kilayim 5:2:1" href="/Jerusalem_Talmud_Kilayim.5.2.1">Mishnah Kilaim 5:2, cf. there, Sheviit 1:2:3" href="/Jerusalem_Talmud_Sheviit.1.2.3">Note 27. Here also, the ox and its harness need four cubits. The rabbis disregard the additional trees and only require one group yielding a talent. R. Simeon forbids ploughing unless one group produces a talent and the remaining three trees (of which two are planted too close together) produce ⅔ of a talent..

הלכה: שְׁלֹשָׁה אִילָנוֹת כו׳. תַּנֵּי רִבִּי חִייָא אִילָנוֹת שֶׁל אָדָם אֶחָד וְקַרְקַע שֶׁל אָדָם אֶחָד מִצְטָֽרְפִין וְחוֹרְשִׁין כָּל־בֵּית סְאָה בִשְׁבִילָן. אָמַר רִבִּי יוֹסָה אַף אֲנָן תַּנִּינָן דְּרָבָא שְׁלֹשָׁה אִילָנוֹת שֶׁל שְׁלֹשָׁה אֲנָשִׁים הֲרֵי אֵלּוּ מִצְטָֽרְפִין וְחוֹרְשִׁין כָּל־בֵּית סְאָה עַד רֹאשׁ הַשָּׁנָה. HALAKHAH: “Three trees, etc.” Rebbi Ḥiyya stated: Trees belonging to one owner and ground belonging to a second owner are counted together and one may plough the entire bet seah for them. Rebbi Yose said, we have stated more: Three trees belonging to three different owners are counted together and one may plough the entire bet seah until the New Year⁴⁵The clearest formulation is in Tosephta Ševi‘it 1:1: “Three trees belonging to three different owners and the field belonging to a forth. Even though the field’s owner plough for his own needs, the field is permitted [to be ploughed].”.