From The Collaborative International Dictionary of English v.0.48 :
Campestral \Cam*pes"tral\, Campestrian \Cam*pes"tri*an\, a. [L.
campester, fr. campus field.]
Relating to an open field; growing in a field, or open
ground.
[1913 Webster]
From WordNet (r) 2.0 :
campestral
adj : of fields or open country; "living in campestral seclusion"