Bava Metzia 106B

חזינא? קשיא.

I was worthy. The Talmud concludes: Indeed, this is difficult.

תני חדא: פעם ראשונה ושניה זורעה, ושלישית אינו זורעה. ותניא אידך: שלישית זורעה, רביעית אינו זורעה. לא קשיא: הא כרבי, הא כרבן שמעון בן גמליאל.

§ It is taught in one baraita: With regard to one who cultivates a field, the first and second time he plants the field again if the crops were destroyed by some mishap, but the third time he is not required to plant it again. And it is taught in another baraita that on the third occasion, he must plant it the field again, but after the 4th time the crops are destroyed, he is not required to plant it again. These two baraitot appear to contradict one another. The Talmud explains: That is not difficult, as this baraita is in accordance with the opinion of R' Yehuda HaNasi, whereas that baraita is in accordance with the opinion of Rabban Shimon ben Gamliel.

הא כרבי, דאמר: בתרי זימני הוי[א] חזקה. הא כרבן שמעון בן גמליאל, דאמר: בתלת זימני הוי[א] חזקה.

The Talmud clarifies: This baraita is in accordance with the opinion of R' Yehuda HaNasi who says that presumptive status is established by two occasions, while that baraita is in accordance with the opinion of Rabban Shimon ben Gamliel, who says that presumptive status is established by 3 occasions.

אמר ריש לקיש: לא שנו אלא שזרעה וצמחה ואכלה חגב. אבל זרעה ולא צמחה ⁠– מצי אמר ליה בעל הקרקע: כל ימי זרע זרעא לה ואזיל. ועד אימת? אמר רב פפא: עד דאתו אריסי מדברא וקיימא כימה ארישייהו.

Reish Lakish said: They taught that a cultivator plants a limited number of times only if he planted the field and it sprouted and locusts consumed the crops, but if he planted it and the crops did not sprout at all, the landowner can say to him: You should continue planting it on all the days that are fit for planting. The Talmud asks: And until when does the period of planting last? The Talmud answers: Rav Pappa said: Until such time that the sharecroppers come in from the field and the stars of Pleiades are stationed over their heads, which occurs roughly during the month of Shevat.