In this passage the printer’s manuscript consistently has “the land of Desolation”. The 1830 edition lacks the of in verse 1, but in verse 2 the of is there. So the immediate implication is that the 1830 edition accidentally dropped the of in verse 1, especially since the stronger tendency is to drop small words rather than add them. Note, however, that later in verse 2 we have “the city Desolation”, without any of, in both 𝓟 and the 1830 edition.
Elsewhere the text consistently reads “the land Desolation” (seven times). Nonetheless, there is evidence that with adjectival names the of does occur, but considerably less frequently. For instance, here in Mormon there are five occurrences of “the city Desolation” (including the one at the end of Mormon 4:2, cited above) but one occurrence of “the city of Desolation” (Mormon 3:7).
Similarly, we have six occurrences of “the city Bountiful” and two of “the city of Bountiful”. And in the original text, there were 19 occurrences of “the land Bountiful” and 4 of “the land of Bountiful”. Moreover, there have been some changes in the occurrence of the of for “the land (of ) Bountiful”—and in both directions: the current text has an added of in one case (in 1 Nephi 17:7); and in two cases, the of has been omitted (in Alma 50:32 and Alma 52:15).
When we consider the early transmission of the text, we find that there are no clear instances where scribe 2 of 𝓟 either added or omitted of in “land (of ) X” or “city (of ) Y”. On the other hand, we find that the 1830 typesetter made changes in both directions:
Thus the chances are greater that here in Mormon 4:1 the 1830 typesetter accidentally omitted the of in “the land of Desolation”. The critical text will consequently accept the reading in 𝓟 as the reading in 𝓞 and thus the original reading.
Summary: Restore in Mormon 4:1 the of in “the land of Desolation”, the reading of the printer’s manuscript; the typesetter for the 1830 edition apparently dropped the of; this change makes verses 1 and 2 both read “the land of Desolation”.