Moed Katan 3a - Hah'orech bacheviit vetossefet cheviit bazman hazé

אִיתְּמַר הַחוֹרֵשׁ בַּשְּׁבִיעִית רַבִּי יוֹחָנָן וְרַבִּי אֶלְעָזָר חַד אָמַר לוֹקֶה וְחַד אָמַר אֵינוֹ לוֹקֶה לֵימָא בִּדְרַבִּי אָבִין אָמַר רַבִּי אִילְעָא קָמִיפַּלְגִי דְּאָמַר רַבִּי אָבִין אָמַר רַבִּי אִילְעָא כׇּל מָקוֹם שֶׁנֶּאֱמַר כְּלָל בַּעֲשֵׂה וּפְרָט בְּלֹא תַעֲשֶׂה אֵין דָּנִין אוֹתוֹ בִּכְלָל וּפְרָט וּכְלָל מַאן דְּאָמַר לוֹקֶה לֵית לֵיהּ דְּרַבִּי אָבִין אָמַר רַבִּי אִילְעָא וּמַאן דְּאָמַר אֵינוֹ לוֹקֶה אִית לֵיהּ דְּרַבִּי אָבִין לָא דְּכוּלֵּי עָלְמָא לֵית לֵיהּ דְּרַבִּי אָבִין אָמַר רַבִּי אִילְעָא מַאן דְּאָמַר לוֹקֶה שַׁפִּיר וּמַאן דְּאָמַר אֵינוֹ לוֹקֶה אָמַר לָךְ מִכְּדִי זְמִירָה בִּכְלַל זְרִיעָה וּבְצִירָה בִּכְלַל קְצִירָה לְמַאי הִלְכְתָא כַּתְבִינְהוּ רַחֲמָנָא לְמֵימַר דְּאַהָנֵי תּוֹלָדוֹת הוּא דְּמִיחַיַּיב אַתּוֹלָדָה אַחֲרִינָא לָא מִיחַיַּיב וְלָא וְהָתַנְיָא...

whereas the subcategories of labor that are derived from them, e.g., watering, were not prohibited by the Merciful One, i.e., by Torah law, but only by rabbinic law; and in a case of loss the Sages were lenient. The source for this distinction is as it is written: “But in the seventh year shall be a sabbath of solemn rest for the land, a sabbath for the Lord: Your field you shall not sow, and your vineyard you shall not prune. That which grows of its own accord of your harvest you shall not reap, nor gather the grapes of your undressed vines” (Leviticus 25:4–5). Since pruning is included in the principal category of sowing, as its objective is to encourage the plant’s growth, and picking grapes is included in the principal category of reaping grain, as both involve removal of produce from a plant, for the purpose of teaching what halakha did the Merciful One write them? Why did the Torah explicitly prohibit pruning and picking grapes, rather than sufficing with the general prohibitions against sowing and reaping? The Gemara answers that these were individually enumerated to say that only for these subcategories of labor is one liable to be flogged, while for other subcategories of labor, i.e., watering a field, one is not liable. Consequently, there are only four types of labor that are prohibited by Torah law during the Sabbatical Year: Sowing and its subcategory of pruning, as well as reaping and its subcategory of grape picking. All other subcategories of labor are prohibited only by rabbinic decree. The Gemara asks: And is there really no liability for other subcategories of labor? Isn’t it taught in a baraita: “Your field you shall not sow, and your vineyard you shall not prune” (Leviticus 25:4). I have derived from here an explicit prohibition only against sowing and pruning. From where do I derive that weeding, i.e., uprooting weeds, hoeing, and cutting weeds, even without uprooting them, are also prohibited? The verse states: “Your field you shall not sow” and “your vineyard you shall not prune.” This wording indicates that no labor may be performed in your field, and no labor may be performed in your vineyard. Similarly, from where is it derived that one may not prune trees, and one may not trim dry branches from trees, and one may not cut large branches [mefasegin] from trees? The verse states: “Your field you shall not sow” and “your vineyard you shall not prune,” thereby teaching that no labor may be performed in your field, and no labor may be performed in your vineyard. Similarly, from where is it derived that one may not fertilize fields and vineyards, and one may not remove stones that surround the base of a tree and impede its growth, and one may not cover exposed roots with dust, and one may not fumigate a tree in order to exterminate worms? The verse states: “Your field you shall not sow” and “your vineyard you shall not prune,” thereby indicating that no labor may be performed in your field, and no labor may be performed in your vineyard. The apparent conclusion from this is that all labor in a field or a vineyard is prohibited. One might have thought that one may also not hoe lightly under olive trees and one may not hoe under grapevines, and one may not fill cracks in the ground with water, and one may not construct circular ditches around the bases of grapevines in order to collect rainwater. Therefore, the verse states: “Your field you shall not sow.” The Gemara explains the derivation: Sowing was included in the general prohibition against performing agricultural labors during the Sabbatical Year, as the verse states “But in the seventh year shall be a sabbath of solemn rest for the land” (Leviticus 25:4). Why was sowing singled out and mentioned explicitly? In order to compare other types of labor to it and to say to you: Just as sowing is unique in that it is labor performed both in the field and in the vineyard, so too, any other labor performed both in the field and in the vineyard is prohibited. However, labors performed only in the vineyard but not in the field, i.e., whose objective is merely to sustain the vines from year to year, such as the labors mentioned above, are permitted. In any case, this baraita indicates that many subcategories of labor are prohibited during the seventh year, and not just sowing and pruning, as Rava had stated. The Gemara rejects this opinion: These labors, with the exceptions of sowing, pruning, grape picking, and reaping, are all prohibited only by rabbinic law, and the verse that is cited as a source from the Torah is a mere support, and not a bona fide source. Incidental to this discussion, the Gemara asks: Is light hoeing under olive trees in fact permitted during the Sabbatical Year? Isn’t it written: “But the seventh year you shall let it rest and lie fallow” (Exodus 23:11), and it is taught with regard to this verse: “You shall let it rest” from light hoeing, “and lie fallow” from clearing the field of stones. This indicates that light hoeing is indeed prohibited during the Sabbatical Year. Rav Ukva bar Ḥama said: There are two types of light hoeing, one whose objective is to strengthen the trees, and another that is intended to seal cracks. There is a practical halakhic difference between them: Hoeing performed in order to strengthen the tree is prohibited, as it is similar to plowing in that it enhances the tree’s growth. However, hoeing undertaken in order to seal cracks is permitted, as by doing so one prevents damage to the tree. § It was stated that Rabbi Yoḥanan and Rabbi Elazar disagreed with regard to one who plows during the Sabbatical Year. One said: He is flogged for doing so, while the other one said: He is not flogged. The Gemara suggests: Let us say that they disagree with regard to the principle that Rabbi Avin said that Rabbi Ile’a said, and one accepts this principle while the other does not. As, Rabbi Avin said that Rabbi Ile’a said: Wherever a generalization is stated in the Torah as a positive mitzva, and a detail relating to that generalization is stated as a negative mitzva, one does not apply the hermeneutical principle of a generalization, and a detail, and a generalization, according to which the halakha under discussion is expanded to all cases that resemble the detail. The Gemara explains: The one who said that one who plows during the Sabbatical Year is flogged does not accept the principle that Rabbi Avin said that Rabbi Ile’a said. Accordingly, he expounds the verses as follows: The verse “But in the seventh year shall be a sabbath of solemn rest for the land” (Leviticus 25:4) is a generalization stated as a positive mitzva. The continuation of the verse is “Your field you shall not sow,” which is a detail stated as a negative mitzva. This is followed by another generalization: “For it shall be a year of rest for the land” (Leviticus 25:5). By applying the principle of a generalization, a detail, and a generalization, one can derive that there is a prohibition against performing any agricultural task that is similar to sowing, including plowing. And the one who said that one is not flogged for plowing holds in accordance with the ruling that Rabbi Avin stated in the name of Rabbi Ile’a. Therefore, the prohibition stated as a detail, i.e., the prohibition against sowing, is not extended to include any other labor. One who plows violates the positive command to let the land rest, but does not transgress a Torah law phrased as a negative mitzva, and therefore he is not flogged. The Gemara rejects this suggestion: No, one can say that everyone holds that the halakha is not in accordance with the principle that Rabbi Avin said that Rabbi Ile’a said. According to the one who said he is flogged, all is well, as he applies the hermeneutical principle of a generalization, a detail, and a generalization to derive a prohibition for plowing. And the one who said that he is not flogged could have said to you: Since pruning is included in the primary category of sowing, and grape picking is included in the primary category of reaping, for the purpose of teaching what halakha did the Merciful One write them? They were individually enumerated to say that only for these specific subcategories of labor is one liable to be flogged, but for performing other subcategories of labor one is not liable. According to this opinion, the verse comes to teach that one is not liable to be flogged for performing any labor not explicitly enumerated in the Torah, including plowing. The Gemara asks: And is there really no liability for other subcategories of labor? Isn’t it taught in a baraita with regard to the verse “Your field you shall not sow, and your vineyard you shall not prune” that I have derived from here an explicit prohibition only against sowing and pruning? From where do I derive that weeding, hoeing, and cutting weeds are also prohibited? The verse states: “Your field you shall not sow and your vineyard you shall not prune” (Leviticus 25:4). By placing the word “not” immediately following the words “field” and “vineyard,” the verse indicates that one may not perform any labor that is generally performed in your field, and one may not perform any labor that is generally performed in your vineyard. Similarly, from where is it derived that one may not prune trees, and one may not trim dry branches from trees, and one may not cut large branches from trees? The verse states: “Your field you shall not sow and your vineyard you shall not prune,” indicating that any labor that is generally performed in your field may not be performed during the Sabbatical Year, and any labor generally performed in your vineyard may not be performed during the Sabbatical Year. From where is it derived that one may not fertilize fields and vineyards, and one may not remove stones from around the base of a tree that impede its growth, and one may not fumigate a tree in order to exterminate worms? The verse states: “Your field you shall not sow and your vineyard you shall not prune,” thereby indicating that any labor that is generally performed in your field may not be performed during the Sabbatical Year, and any labor generally performed in your vineyard may not be performed during the Sabbatical Year. One might have thought that one may also not hoe lightly under olive trees and one may not hoe under grapevines, and one may not fill cracks in the ground with water, and one may not construct circular ditches around the bases of grapevines in order to collect rainwater. Therefore, the verse states: “Your field you shall not sow.” Sowing was included in the general prohibition against performing agricultural labors during the Sabbatical Year. Why was sowing singled out and mentioned explicitly? In order to compare other types of labor to it and to say to you: Just as sowing is unique in that it is labor performed both in the field and in the vineyard, so too, any other labor performed both in the field and in the vineyard is prohibited. However, labor performed only in the vineyard, but not in the field, i.e., whose objective is merely to sustain the vines from year to year, is permitted. In any case, this baraita indicates that many labors are prohibited during the seventh year, and not just sowing and pruning. The Gemara rejects this opinion: These labors, with the exceptions of sowing, pruning, grape picking, and reaping, are all prohibited only by rabbinic law, and the verse that is cited as source from the Torah is a mere support, and not a bona fide source.

וְאָמַר רַבִּי שִׁמְעוֹן בֶּן פַּזִּי אָמַר רַבִּי יְהוֹשֻׁעַ בֶּן לֵוִי מִשּׁוּם בַּר קַפָּרָא רַבָּן גַּמְלִיאֵל וּבֵית דִּינוֹ נִמְנוּ עַל שְׁנֵי פְּרָקִים הַלָּלוּ וּבִטְּלוּם...

And Rabbi Shimon ben Pazi said that Rabbi Yehoshua ben Levi said in the name of bar Kappara: Rabban Gamliel and his court discussed and then voted about the prohibitions of these two periods, i.e., from Passover or Shavuot until Rosh HaShana, and nullified them, thereby permitting plowing until Rosh HaShana, the actual beginning of the Sabbatical Year.
אֶלָּא אָמַר רַב אָשֵׁי רַבָּן גַּמְלִיאֵל וּבֵית דִּינוֹ סָבְרִי לַהּ כְּרַבִּי יִשְׁמָעֵאל דְּאָמַר הִלְכְתָא גְּמִירִי לַהּ וְכִי גְּמִירִי הִלְכְתָא בִּזְמַן שֶׁבֵּית הַמִּקְדָּשׁ קַיָּים דּוּמְיָא דְּנִיסּוּךְ הַמַּיִם אֲבָל בִּזְמַן שֶׁאֵין בֵּית הַמִּקְדָּשׁ קַיָּים לָא:
Rather, Rav Ashi said: Rabban Gamliel and his court held in accordance with the opinion of Rabbi Yishmael, who said that they learned this prohibition as a halakha transmitted to Moses from Sinai. But they learned this halakha only with regard to the time period when the Temple is standing. This is evidenced by the fact that it is similar to the other halakha stated along with it, that of the water libation, which was part of the service in the Temple. But when the Temple is not standing this halakha does not apply, and therefore Rabban Gamliel and his court nullified the prohibition after the destruction of the Temple.
מִצְוַת עֲשֵׂה לִשְׁבֹּת מֵעֲבוֹדַת הָאָרֶץ וַעֲבוֹדַת הָאִילָן בְּשָׁנָה שְׁבִיעִית שֶׁנֶּאֱמַר (ויקרא כה ב) "וְשָׁבְתָה הָאָרֶץ שַׁבָּת לַה'" וְנֶאֱמַר (שמות לד כא) "בֶּחָרִישׁ וּבַקָּצִיר תִּשְׁבֹּת". וְכָל הָעוֹשֶׂה מְלָאכָה מֵעֲבוֹדַת הָאָרֶץ אוֹ הָאִילָנוֹת בְּשָׁנָה זוֹ בִּטֵּל מִצְוַת עֲשֵׂה וְעָבַר עַל לֹא תַּעֲשֶׂה שֶׁנֶּאֱמַר (ויקרא כה ד) "שָׂדְךָ לֹא תִזְרָע וְכַרְמְךָ לֹא תִזְמֹר":
It is a positive commandment to refrain from working the land and caring for trees in the seventh year, as it says, "and the land shall rest a Sabbath for the Lord" (Leviticus 25:2), and it says "in plowing and in harvesting you shall rest" (Exodus 34:21). Anyone who performs one of the forbidden labors from the working of the land or caring for trees in this year has abrogated a positive commandment and transgressed a negative commandment, as it says, "you shall not plant your field, nor shall you prune your vineyard" (Leviticus 25:4).
מִצְוָתוֹ לְהִקָּצֵר בַּלַּיְלָה בְּלֵיל שִׁשָּׁה עָשָׂר. בֵּין בְּחל בֵּין בְּשַׁבָּת:
עֲבוֹדַת הָאָרֶץ בְּשָׁנָה שִׁשִּׁית שְׁלֹשִׁים יוֹם סָמוּךְ לַשְּׁבִיעִית אֲסוּרָה הֲלָכָה לְמשֶׁה מִסִּינַי. מִפְּנֵי שֶׁהוּא מְתַקְּנָהּ לַשְּׁבִיעִית. וְדָבָר זֶה בִּזְמַן שֶׁבֵּית הַמִּקְדָּשׁ קַיָּם הוּא שֶׁנֶּאֱסַר מִפִּי הַשְּׁמוּעָה. וְגָזְרוּ חֲכָמִים שֶׁלֹּא יִהְיוּ חוֹרְשִׁים שְׂדֵה הָאִילָן עֶרֶב שְׁבִיעִית בִּזְמַן הַמִּקְדָּשׁ אֶלָּא עַד הָעֲצֶרֶת. וּשְׂדֵה הַלָּבָן עַד הַפָּסַח. וּבַזְּמַן שֶׁאֵין מִקְדָּשׁ מֻתָּרִין בַּעֲבוֹדַת הָאָרֶץ עַד רֹאשׁ הַשָּׁנָה כְּדִין תּוֹרָה:
Working of the land in the sixth year (of the Sabbatical cycle) is forbidden 30 days in advance of the seventh year, as an oral law given to Moses at Sinai, because he prepares it (for planting) in the Sabbatical year. By tradition, this labor is forbidden when the Temple is in existence, but the Rabbis legislated additional restriction, that people should not plow orchards in the eve of Sabbatical year during Temple times except until Shavuot, and grain fields only until Passover. When there is no Temple, it is permitted to work the land until New Year as in the law of the [written] Torah.

Bechaar hamelekh (Chemita veyovel 1:1) bechem haRamban

חרישה וזריעה בשביעית מי שרי פי' מדאורייתא ואפי' למ"ד החורש בז' אינו לוקה מודה דאפי' בערב שביעית למד יום איסור תורה או מהלכה אי מקראי כדאיתא לקמן וכ"ש בשביעית עצמה דאתי בק"ו:

Ran (1:2 bedapei haRif) vehaRoch (Cheviit 2:4)

מתני' (דף ב.) באחד בתשרי ראש השנה לשנים ולשמיטים וליובלות לנטיעה ולירקות.
לשמיטין וליובלות. משנכנס תשרי אסור לחרוש ולזרוע מן התורה:
ובשדה האילן עד העצרת. בפ"ק דמ"ק מייתי לה. ירושל' (הל' א) לא סוף דבר בשיש לו מוקשה ומדלעת אלא אפי' מאחר שבני אדם עתידין ליטע במקשאות ובמדלעות מותר ר"ש אומר נתת תורת כל אחד ואחד בידו זה אומר כלתה ליחה בתוך שלי וזה אומר לא כלתה ליחה בתוך שלי אלא בשדה הלבן עד הפסח בשדה האילן עד העצרת מה בין שדה אילן לשדה לבן שדה לבן על ידי שעתיד לזורעה בתחלה צריך שתהא רוב הליחה קיימת שדה אילן ע"י שנטוע כבר אינו צריך שתהא רוב הליחה קיימת:
יש חורש תלם א' וחייב עליו משום שמונה לאוין החורש בשור וחמור והן מוקדשין וכלאים בכרם ובשביעית ויום טוב וכהן ונזיר בבית הטומאה
Apropos the case where one receives several sets of lashes for performing a single action, the mishna continues: There is one who plows a single furrow and is liable to receive lashes for violating eight prohibitions. How so? For plowing with an ox and a donkey, in violation of the prohibition: “You shall not plow with an ox and a donkey together” (Deuteronomy 22:10); and they are consecrated, and therefore he is guilty of misuse of consecrated property; and he is plowing diverse kinds in a vineyard; and it is during the Sabbatical Year, when it is prohibited to work the land; and it is on a Festival, when plowing is a prohibited labor; and he is both a priest and a nazirite and is performing the plowing in a place of impurity imparted by a corpse, which is prohibited for both a priest (see Leviticus 21:1) and a nazirite (see Numbers 6:6).
יש חורש תלם אחד - יש עובר בלא תחרוש בשור ובחמור ונלקטים עליו איסורים הרבה עם אותו לאו בלבד ובהא לא קא עסיק שיהא חורש בכמה שוורים וכמה חמורים והרי נלקטים איסורין הרבה עליו דלכל הפחות קאמר ואלאו דכלאים קאי ללקוט עליו כל איסורין שהוא יכול:

וּדְמוֹסִיפִין מֵחוֹל עַל קֹדֶשׁ מְנָלַן דְּתַנְיָא בֶּחָרִישׁ וּבַקָּצִיר תִּשְׁבּוֹת

And the Rabbis, who do not require an additional verse to derive that the Jubilee Year does not extend until Yom Kippur of the fifty-first year, derive a this halakha from the verse: You count the fiftieth year as the Jubilee Year alone, but you do not count the fiftieth year as the Jubilee Year and also as the first year of the next Sabbatical cycle. This halakha comes to exclude the opinion of Rabbi Yehuda, who said that the fiftieth year is counted for here and for there, both as the Jubilee Year and also as the first year of the next Sabbatical cycle. Lest someone think that that is the case, therefore, the verse teaches us that this is not so; rather, the fiftieth year is the Jubilee Year, and the following year is the first year of the next Sabbatical cycle. § Apropos of the discussion of extending the Jubilee year, the Gemara asks: From where do we derive the principle that one extends a sanctified time period by adding from the profane to the sacred at both ends? As it is taught in a baraita: The verse states: “In plowing and in harvest you shall rest” (Exodus 34:21). Rabbi Akiva says: It is unnecessary to state this about plowing and harvesting during the Sabbatical Year, as it is already stated: “But in the seventh year shall be a Shabbat of solemn rest for the land, a Shabbat for the Lord; you shall neither sow your field, nor prune your vineyard” (Leviticus 25:4). Rather, the verse: “In plowing and in harvest you shall rest,” is referring to plowing in the year preceding the Sabbatical Year going into the Sabbatical Year, i.e., plowing in the sixth year that will benefit the crops growing in the Sabbatical Year, and about harvesting of the Sabbatical Year going into the year that follows the Sabbatical Year, i.e., harvesting grain that grew in the Sabbatical Year in the eighth year. This teaches that there is a requirement to add extra time to the sanctity of the Sabbatical Year, and not work the land both before and after. The baraita continues: Rabbi Yishmael says that the verse: “In plowing and in harvest you shall rest,” is not referring to the prohibition against farming the land before and after the Sabbatical Year as Rabbi Akiva explains. He explains that the reason that the verse mentions these two particular forms of labor is to teach that just as the type of plowing that is prohibited during the Sabbatical Year is an otherwise voluntary act, as plowing is never required by the Torah, so too, the harvesting that is prohibited during that year is only voluntary harvesting. This comes to exclude the harvesting of the omer from the prohibition, as it is a mitzva. The barley for the omer must be harvested on the sixteenth of Nisan. Consequently, it is permitted to harvest the omer even during the Sabbatical Year. The Gemara asks: If so, from where does Rabbi Yishmael derive this principle that one extends a sacred time period by adding from the profane to the sacred both before and after? The Gemara answers: He derives it from that which is taught in a baraita: The verse states, in reference to Yom Kippur: “And you shall afflict your souls on the ninth of the month in the evening” (Leviticus 23:32). One might have thought that one must begin to fast the entire day on the ninth of the month. Therefore, the verse states: “In the evening.” But if it is so that Yom Kippur begins in the evening, one might have thought that one need only begin to fast from when it is dark, after nightfall, when the tenth day of the month begins. Therefore, the verse states: “On the ninth.” How so; how is this to be accomplished? One begins to fast on the ninth of the month while it is still day. This teaches that one extends a sacred time period by adding at the beginning from the profane to the sacred. From here I have derived only that this addition is made at the beginning of Yom Kippur. But from where do I derive that a similar addition is made at the end of Yom Kippur? The verse states: “From evening to evening shall you rest on your Shabbat” (Leviticus 23:32), which teaches that just as Yom Kippur is extended at the beginning, so too, it is extended at the end. From here I have derived only that an extension is added to Yom Kippur. From where is it derived that one must also extend Shabbat? The verse states: “You shall rest [tishbetu],” which is referring to Yom Kippur but alludes to Shabbat. From where do I know that the same applies to Festivals? The verse states: “Your Shabbat [shabbatkhem],” your day of rest. How so? Wherever there is a mitzva of resting, be it Shabbat or a Festival, one adds from the profane to the sacred, extending the sacred time at both ends. The Gemara asks: And Rabbi Akiva, who learns that one adds from the profane to the sacred from the verse dealing with the Sabbatical Year, what does he do with this verse: “And you shall afflict your souls on the ninth of the month in the evening”? The Gemara answers: He requires it for that which was taught by Ḥiyya bar Rav of Difti, as Ḥiyya bar Rav of Difti taught the following baraita: The verse states: “And you shall afflict your souls on the ninth of the month.” Is the fasting on the ninth? But isn’t the fasting on Yom Kippur on the tenth of Tishrei? Rather, this verse comes to teach you: Whoever eats and drinks on the ninth, thereby preparing himself for the fast on the next day, the verse ascribes him credit
ורבי ישמעאל מוסיפין מחול על הקודש מנא ליה. תימה לר"ת הא אמרינן פ"ק דמועד קטן (דף ד.) הלכתא לרבי ישמעאל קראי לר"ע דעשר נטיעות הלכה למשה מסיני וכיון דהלכתא למשרי ילדה ממילא זקנה אסורה ותירץ ר"ת דהכא מיבעי ליה בתוספת של אחר שביעית מנא ליה ובחנם דחק דכיון דשביעית גופה מהלכה לא ילפינן מינה שבת ויוה"כ וי"ט דאין דנין ק"ו מהלכה והשתא לר' ישמעאל איצטריך קרא משום שבת וי"ט ואיצטריך. הלכתא למשרי ילדה והא דלא משני הכי במו"ק לר"ע דאיצטריך קרא ללמד על שבת וי"ט ויוה"כ משום דמהלכה לא ילפי' דא"כ לא הוי ליה למכתב קראי גבי שביעית כיון דלשביעית גופיה לא צריך אלא ללמד על אחריני:
אלא חריש של ערב שביעית הנכנסת לשביעית. פי׳ שהיא מועלת בשביעית וזה מן התורה שלשים יום קודם שביעית וחכמים הוסיפו בשדה אילן מן הפסח ובשדה לבן מן העצרת דבהכי מועילין בשביעית:
וקציר שביעית היוצא למוצאי שביעית. פרש״י כגון תבואה שהביאה שליש בשביעית וא״ת א״כ למה לי משום תוס׳ שביעית הא אסירא מדין פירות שביעית כדנפקא לן מדכתיב ועשת את התבואה לשלש השנים אל תקרי לשלש אלא לשליש וי״ל דהכא לא הוצרכו לאסור הפירות אלא לאסור כל עבודה בשדה שיש בה באותו קציר במוצאי שביעית עד שתשלש אותה תבואה וזהו תוספת שביעית בסופה:

Meïri (cham)

עֲבוֹדַת הָאָרֶץ בְּשָׁנָה שִׁשִּׁית שְׁלֹשִׁים יוֹם סָמוּךְ לַשְּׁבִיעִית אֲסוּרָה הֲלָכָה לְמשֶׁה מִסִּינַי. מִפְּנֵי שֶׁהוּא מְתַקְּנָהּ לַשְּׁבִיעִית. וְדָבָר זֶה בִּזְמַן שֶׁבֵּית הַמִּקְדָּשׁ קַיָּם הוּא שֶׁנֶּאֱסַר מִפִּי הַשְּׁמוּעָה. וְגָזְרוּ חֲכָמִים שֶׁלֹּא יִהְיוּ חוֹרְשִׁים שְׂדֵה הָאִילָן עֶרֶב שְׁבִיעִית בִּזְמַן הַמִּקְדָּשׁ אֶלָּא עַד הָעֲצֶרֶת. וּשְׂדֵה הַלָּבָן עַד הַפָּסַח. וּבַזְּמַן שֶׁאֵין מִקְדָּשׁ מֻתָּרִין בַּעֲבוֹדַת הָאָרֶץ עַד רֹאשׁ הַשָּׁנָה כְּדִין תּוֹרָה:
Working of the land in the sixth year (of the Sabbatical cycle) is forbidden 30 days in advance of the seventh year, as an oral law given to Moses at Sinai, because he prepares it (for planting) in the Sabbatical year. By tradition, this labor is forbidden when the Temple is in existence, but the Rabbis legislated additional restriction, that people should not plow orchards in the eve of Sabbatical year during Temple times except until Shavuot, and grain fields only until Passover. When there is no Temple, it is permitted to work the land until New Year as in the law of the [written] Torah.

Chout H'ovat Yaïr (192:17)

יש אומרי' שצריך להוסיף מחול על הקודש וזמן תוספת זה הוא מתחלת השקיע' שאין השמש נראת על הארץ עד זמן בין השמשות והזמן הזה שהוא ג' מילין ורביע רצה לעשותו כולו תוספת עושה רצה לעשות ממנו מקצת עושה ובלבד שיוסיף איזה זמן שיהיה ודאי יום מחול על הקודש ושיעור זמן בין השמשות הוא ג' רבעי מיל שהם מהלך אלף ות"ק אמות קודם הלילה: הגה ואם רוצה להקדים ולקבל עליו השבת מפלג המנחה ואילך הרשות בידו (טור ואגור בשם תוס' פ' תפלת השחר) [וע"ל סי' רס"ז]:
2. There are those who say that we must add from the weekday (mundane) to the holy and the time of this addition is from the beginning of sunset, i.e., when the sun is no longer visible on the earth’s [horizon], until bein hashmashos. This period is equivalent to the time [sufficient to walk] three-and-a-quarter mil (this is approx. 60 minutes). If one desires to deem this entire period of time as tosefes Shabbos (the addition to Shabbos), he may. If he wants to add less, he may. This is provided that one will add some amount of time when it is certainly day from the mundane to the holy. The time of bein hashemashos is 3/4 mil, which is like walking approximately 960 meters or .596 of a mile before nightfall. RAMA: And if one wishes to do this earlier and accepts Shabbos upon himself from Plag Hamincha and onward, he may do so. (Tur; Agur in the name of Tosefos)[See Siman 267].
סדר סעודה המפסקת. ובו ד סעיפים:
אוכלין ומפסיקין קודם בין השמשו' שצריך להוסיף מחול על הקודש ותוספת זה אין לו שיעור אלא קודם בין השמשו' שזמנו אלף ות"ק אמה קודם הלילה צריך להוסיף מחול על הקודש מעט או הרבה:
1. The Order of the Concluding Meal and in it is 4 paragraphs. We eat and stop before Bein Hashamashos (Twilight). Due to it is necessary to add from the weekday to the Holy (day of Yom Kippur). And this added time does not have a measure (i.e. a Halachic minimum requirement). Rather prior to Twilight whose time is (the amount time to walk) 1500 amah (amah is a halachic measure between 48-60 centimeters) before the Night, it is necessary to add from the weekday to the Holy day, a little or a lot.