Question juridique clé
Whether the 31 July 1991 termination of the mixed management contract was valid against Y.________ SA
Solution extraite
Yes. The contract was validly terminated vis-à-vis Y.________ SA as of 31 August 1991.
Motifs extraits
The contract was a mixed sui generis transfer agreement governed by the rules fitting its predominant alienation element, not by lease-for-agriculture rules. The contractual termination clause displaced any grace-period requirement, and no protected reliance or reviving agreement bound Y.________ SA.