ITHACA, N.Y., April 12--Student opposition to compulsory ROTC at Cornell will reach its climax on April 20, when the entire student body votes in a special referendum on whether or not ROTC training should be mandatory.

Ever since the passage of the Merrill Land Grant Acts in the 1860's, Cornell has had compulsory two-year military training for all physically fit male undergraduates. The provisions of the Acts force Cornell to offer ROTC courses, but do not compel the school to make the courses mandatory.

Student groups, headed by the Student Council and the Cornell Daily Sun, have led a drive to make ROTC training purely voluntary. The campaign was instigated principally by the recent law which forces every ROTC student to sign a loyalty oath, stating that he has never belonged to a subversive organization. This, students charge, is unwarranted government interference in education.

Theoretically, if a student refuses to sign the oath he would be subject to expulsion, but in reality, only one student has not signed so far and he sits in a "special" class and is given private logistic instruction.

The two faculty committees involved in the ROTC squabble, The Committees on Military Curricula and Requirements for Graduation, have so far supported the status quo, and will recommend no change to the Faculty in May.

However, the Student Council, unanimously supporting a change, has planned the referendum to present the students' reaction.