Arlington School Superintendent Larry Cuban recommended last night that the county's Ashlawn and Jackson elementary schools be closed at the end of this school year because of declining enrollment.

Cuban's recommendation is expected to provoke heated opposition from supporters of the two schools who will get an opportunity to challenge his suggestions at a school board hearing before a final decision is made in December.

At a school board meeting last night, Joan Horwitt, president of the Ashlawn Coalition, said, "the justification given for closing Ashlawn . . . is totally unacceptable." Horwitt, whose organization gave the board a petition with 1,000 signaturs last month, declared: "I don't think Ashlawn has gotten a fair shake."

Both of the schools Cuban urged closing are located in the northwest portion of the county. Ashlawn is at 5950 8th Road and Jackson is at 850 N. George Mason Drive.

Arlington's public school enrollment has dropped by 10,000 students during the last 10 years. During that same time, elementary school enrollment has fallen from 13,775 to 8,825 and school officials say they expect an annual 4 to 5 percent decrease in school enrollment to continue until 1984.

The country has closed 12 elementary schools since 1970 but most of the closings were for reasons other than shrinking enrollment. Another elementary school, Fort Myer, is scheduled to be closed in June 1980.

"The changing nature of the country -- fewer married couples of childbearing age, a larger percentage of senior citizens, conversion of apartments to high-rise or condominiums . . . and a declining birthrate have contributed to the loss in students," Cuban had cautioned the school board in September.

That report examined seven schools, all in North Arlington, as possible candidates for closing. Two of the seven, Barrett and Glencarlyn, were dropped from the list at that time because enrollments at each had remained "relatively stable" for the last six years.

Last night's recommendations suggested that Tuckahoe and McKinley remain open because both have superior facilities.

The remaining three schools, Jackson, Ashlawn and Reed, were evaluated and compared against four criteria -- capacity, access to community resources, the number of students who would need to be bused to a new school, and quality of their facilities.

Cuban recommended Jackson as his first choice for closing because he said it had the "least desirable physical plant." Second choice was Ashlawn because, said Cuban, it ranked lower than Reed based on access to community resources, number of students who will need busing and capacity.

The public hearing on the closings is scheduled for Nov. 8. The board will make its final decision on which schools to close Dec. 6.