PS

*ŝadaw- - open country, wild, uncultivated place (Fronzaroli 1968: 269‒270, 287; Kogan 2011: 190; Kogan 2015: 307)

reconstruction with *-w (rather than -y) seems to be assured by well-attested spellings with -u-/-w- in Sargonic (śa-dú-e, śa-dú-im) and Old Assyrian (ša-ad-wi-im, ša-du-im), v. Kienast 1994:278‒280 and CAD Š₁ 51 respectively

PC
*ŝaday- - (cultivated) field (Kogan 2015: 307)
The meaning “cultivated field” for *ŝadaw- is a highly specific PC innovation with no precedent in other Semitic languages, where this concept is expressed, inter alia, by the reflexes of PS *ḥaḳl- (Fronzaroli 1969 :8‒9, 26)

Akkadian
šadû - mountain; open country (CAD Š₁ 49, AHw. 1124)
Hebrew
ŝādǟ - pasture, open fields; field, arable land (HALOT 1307)
Mandaic
sadia - field, open space, plain, desert (MD 310)
Sabaic
s₂dw - mountain; cultivated land (SD 131, Biella 511)