THIS WAS TO BE the year Congress put an end to the great Alaskan land controversy. It had given itself a deadline of Dec. 18 by which to decide what parts of Alaska should be developed and what parts preserved as parks, wilderness and other federally protected areas. But unless the Senate Energy and Natural Resources Committee can conclude its deliberations quickly, there is little chance the deadline will be met. And if it is not, the struggle that has dominated Alaska affairs for more than a decade will become even more difficult.

The Senate committee has been working on the matter for months now. While generally accepting the geographic areas approved for federal protection by the House, the committee has been steadily lowering the level of protection. Millions of acres designed by the House as wilderness, where logging and mining would be prohibited, have been downgraded so those activities would become permissible. Millions of other acres approved by the House as national parks or wildlife refuges have been similarly downgraded. The Senate committee still has to consider what many regard to be the hardest questions - those involving southeastern Alaska, where an existing timber industry wants logging rights on some of the state's most beautiful and accessible land. The way the committee deals with these questions - especially those involving Admiralty Island, where the natives want wilderness and the timber companies want logs, - may determine the legislation's fate.

The extensive changes already made in the House bill would present problems at any time. But the problems are exceptionally acute this year. Even if the filibuster threated by Alaska's senators is cut off or does not materialize, passage by the Senate of the committee's bill as it stands will guarantee long and hard negotiations leadership hopes to adjourn in three weeks, not much time is left for what has rightly been called "the land and wildlife conservation votes of the century."

Indeed, part of the strategy of senators who think the House was influenced too much by conservationists and too little by developers seems to be to present the House with the choice of accepting a Senate bill or passing no legislation at all. The problem with carrying the argument over until next year is that the moratorium on development of 87 million acres imposed by Congress in 1971 expires in December. The administration has promised to do everything in its power to protect the land in the absense of congressional action, but it is not clear whether that powe would be sufficient to maintain the status quo. If the Senate committee cannot report a bill promptly, it should recommend extending and expanding the moratorium. The issues involved in this struggle are too important, to the country as a whole as well as to Alaska, to be left dangling because a deadline was not met.