Leviticus 11:38

“But if [any] water be put upon the seed, etc.] Either accidentally or on purpose; whether on sowing seed, and with water with which they water the field, as Aben Ezra interprets it; or on seed used for food, by steeping it in water, as sometimes wheat is, and boiled; and whether it is water or the rest of the liquors, and whether they are put on the seed, or the seed falls into them, it matters not, as Jarchi says: and [any part] of their carcass fall thereon; that is, on the seed, though Aben Ezra observes, some say upon the water: the Targum of Jonathan adds, in its moisture, or while it is wet; and so may be thought to be more susceptible of impurity from the touch of a dead reptile, or…”

“If any water - The reason of the difference is, because wet seed doth sooner receive, and longer retain any pollution and partly because such seed was not fit to be sown presently, and therefore that necessity which justified the use of the dry seed, could not be pretended in this case. Leviticus 11:39”