Genesis 13:6 Commentary: Rashi, Sforno, Radak & Malbim

ולא נשא אתם AND THE LAND WAS NOT ABLE TO BEAR THEM — It could not provide sufficient pasture for their cattle. The phrase is elliptical and a word must be supplied, for instance: the pasturage (מרעה) of the land was not able to bear them — for this reason the word נשא (masculine) is used (to agree in gender with מרעה; the suggestion is that נשא cannot have הארץ as subject since that noun is feminine).

ולא נשא אותם הארץ, the grazing land available in that region was inadequate for their combined herds.

ולא נשא אותם הארץ, in this instance the noun ארץ is treated as a masculine noun, as it is also in Isaiah 9,18 נעתם ארץ, “the earth was shaken.”