is it not right that one day should count as a full year at the beginning of the year?

Rather, what opinion does it follow? If the baraita was not taught in accordance with the opinion of Rabbi Meir, does it follow the opinion of Rabbi Elazar, who holds that only thirty days are considered like a year? If so, then thirty days and another thirty days are required: Thirty days for the planting to take root, and another thirty days to count as a year. As we learned in a mishna: One may not plant, layer, or graft trees on the eve of the Sabbatical Year less than thirty days before Rosh HaShana, and if one planted, layered, or grafted, he must uproot it, as the planting will take root only in the seventh year; this is the statement of Rabbi Elazar. Rabbi Yehuda says: Any grafting that does not take root within three days will never take root. Rabbi Yosei and Rabbi Shimon say: Two weeks are needed for the planting to take root.

And on this topic Rav Naḥman said that Rabba bar Avuh said: According to the statement of the one who says thirty days, this means that it requires thirty days for the planting to take root and another thirty days to count as a year. And according to the statement of the one who says three days, this means that it requires thirty-three days. And according to the statement of the one who says two weeks, this means that it requires two weeks for the planting to take root and another thirty days to count as a year. And if the tanna of the mishna holds in accordance with the opinion of Rabbi Yehuda that only three days are needed for the planting to take root, it still requires three days for the planting to take root and thirty days to count as a year. If so, the baraita cannot be understood even in accordance with the opinion of Rabbi Elazar.

Rather, it must be understood as follows: The baraita was actually taught in accordance with the opinion of Rabbi Meir, and when it says thirty days, it is referring to the time needed for the planting to take root.

The Gemara raises a difficulty: If so, it requires thirty-one days; thirty days for the planting to take root and one more day to count as a year. The Gemara answers: This is theoretically correct, but he holds that the thirtieth day is counted for here and for there, i.e., it counts as both the thirtieth day for taking root and as a day that is counted as a year.

Rabbi Yoḥanan said: And both of them, Rabbi Meir and Rabbi Elazar, who disagree about how much time must pass to count as a year, expounded the same verse. As the verse states: “And it came to pass in the one and six hundredth year, in the first month on the first day of the month, that the waters were dried up from off the earth” (Genesis 8:13). Rabbi Meir holds: From the fact that it was only one day into the year, as it was still the first day of the first month, and yet it is called the six hundred and first year, learn from here that one day in a year is already considered a year.

And the other tanna, Rabbi Elazar, expounds the verse as follows. If it had written: In the six hundred and first year, it would be as you said. However, now that it is written: “In the one and six hundredth year," I can say that the word “year” relates to “six hundredth,” thereby teaching that it is still considered the six hundredth year. And what is meant by “one”? That it is the beginning of one year, but not that the first day counts as a year.

The Gemara asks: And with regard to Rabbi Elazar, what is the rationale for his opinion? From where does he learn that thirty days are counted as a year? As it is written: “In the first month on the first day of the month.” Since it was only one day into the month, and yet it is called a month, learn from here that one day in a month is already considered a month. And since one day in a month is already considered a month, likewise thirty days in a year are already considered a year, as a month is calculated according to its unit, and a year is calculated according to its unit. If one unit by which a month is calculated, i.e., a day, counts as a full month, so too, one unit by which a year is calculated, i.e., a month, counts as a full year.

§ The Gemara comments: By inference, both of them, Rabbi Meir and Rabbi Elazar, hold that the world was created in Nisan and that the years are counted from that month, as, if the world were created in Tishrei and the count started then, the first day of the first month of the six hundred and first year would already have been six months into the year for the purpose of counting years.

It is taught in a baraita that the tanna’im disagreed about this point: Rabbi Eliezer says: In Tishrei the world was created; in Tishrei the Patriarchs were born; in Tishrei the Patriarchs died; on Passover Isaac was born; on Rosh HaShana Sarah, Rachel, and Hannah were remembered by God and conceived; on Rosh HaShana Joseph came out from prison;