Commento su Shevi'it 3:1

מאימתי מוציאיןם זבלים לאשפות – it is the manner of thos who work the land to bring in the manure to one place in the field and make there a large dung-heap until he disperses It in the field to manure it.

Introduction It is forbidden to fertilize the field with manure during the sabbatical year. Furthermore, it is forbidden to bring out the dung used as fertilizer and heap it in the fields because that is the typical first step in the fertilization process. Doing so looks as if they are preparing to fertilize the fields. Therefore they have to wait until the normal time for bringing out the manure has passed before they can bring it out during the sabbatical year. In our mishnah, three sages debate when this time begins. Besides noting that it might not have been so pleasant to live with the dung accumulating in the courtyard, we should also note that this mishnah is an excellent example of sages agreeing on the larger picture (fertilizing is prohibited, and one must wait to bring out the manure) and yet disagree on the details, here when one can bring it out.

משיפסקו עוברי עבירה – to work the land in the Seventh Year and prior to that those who transgress [the laws of the Seventh Year] cease, it is forbidden so that they do not say that this is from those who transgress [the Seventh Year] and that he removes it to manure his field. And there are books in wich it is written them, that those “who perform work” and this is it (i.e., the correct reading).

From when may they bring out manure to the dung-heaps?
From when the workers have ceased to work, the words of Rabbi Meir. According to Rabbi Meir, it becomes permitted to bring out the manure once those who do not observe the sabbatical laws are done doing so. This would have distinguished those who did observe the laws, for they would noticeably take the manure out later than everyone else. As to who the people are who take the manure out on time, they are either non-Jews or perhaps Jews who do not observe these laws.

משייבש המתוק – that the manure will be dried up as it gives a sweetness to the fruits/produce.

But Rabbi Judah says: until the sweetness [of the manure] has dried up. Rabbi Judah says that they have to wait until the manure dries up. This is Rashi’s explanation. Albeck explains that “the sweetness” refers to sweet herbs. Once their moisture is gone it is clearly too late to fertilize and hence it is permitted to bring the manure out into the field.

משיקשר – when it begins to dry up, it thickens and makes clumps/becomes knotty excrescences, and their words are close to being equivalent. And in the Jerusalem Talmud, it explains that when the sweetness dries out, fissures in the group of fields/valley when the rain falls fill up with water and do not dry up other than after a while, and they are called מתוק /sweet on account of (Job 21:33): “The clods of the wadi are sweet to him, [everyone follows ehind hi, innumerable are those who precede him].”

Rabbi Yose says: until [the dung dries] into knots. Rabbi Yose says that they have to wait until the manure itself has dried up.