Commentaire sur Oholot 18:3

נזרעת כל זרע – this is our reading in most of the books. But in the Tosefta (Tractate Ohalot, Chapter 17, Halakha 10), it teaches: אינה נזרעת כל זרע/no seed is sown there (i.e., this is the reverse of what is explicitly taught in our Mishnah). And such it is in my eyes.

A field in which a grave has been lost may be sown with any kind of seed, But must not be planted with any kind of plant; Nor may any trees be permitted to remain there except shade-trees which do not produce fruit. Today's mishnah deals with a field in which a grave has been lost. Such a field may be planted with seed even if the produce will be plucked. We are not concerned lest a piece of bone get stuck to a plant when it is uprooted and that he will bring it into his home (as we were concerned in yesterday's mishnah) because in such a field the bones were not spread around by plowing. The roots of these types of plants will not reach down to where the body was buried, and therefore there is no concern that when they are uprooted, bones will be uprooted as well. However, one cannot plant trees there because their roots do reach down to the grave. It is even forbidden to leave fruit trees there because their roots receive nourishment from the grave. The only type of tree that can be left there is a tree that is meant just for shade and does not yield fruit.

ואין ניטעת כל נטע (and is not planted with any kind of tree) – and needless to say, we don’t plant ab initio. But even that which is planted will not endure/be preserved, so that people will not be accustomed to this, because the defilement in a tent is more stringent in it.

[Such a field] conveys uncleanness by contact, carriage and overshadowing. Since there is an unplowed grave in this field, it conveys impurity in all three ways contact, carriage and overshadowing. In other words, this field is treated more strictly than a field that had a grave but was plowed over.

חוץ מאילן סרק – that it is permitted to plant in it. And what is aאילן סרק ? A tree which bears no fruit).