Administration experts have recommended a sweeping reorganization of te crazy-quilt of federal programs for economic and community development and housing, consolidating them into a new multi-billion-dollar Cabinet department.

Analysis also recommended that President Carter revamp the way the government plans and manages natural resources, from parks to oceans to soil and water conservation ot weather forecasting - putting nearly all these scattered activities into a greatly expanded Department of the Interior.

The recommendations are contained in separate 18-month studies by experts in the Office of Management and Budget. One of Carter's major election campaign promises was a complete reorganization of the federal bureaucracy to make it more effective.

OMB Director James T. McIntyre is expected t send Carter a "decision" memo, based on his expert's studies, by Christmas, sources said, and the president may make a final decision by Jan. 1.

Other major studies on food and nutrition, trade, technology, social services and education are to be completed in a few weeks.

Copies of the studies on economic development and natural resources have been obtained by The Washington Post.

If the president follows the advice of his reorganization experts, the biggest bureaucractic loser would be the Commerce Department, which would see more than half its funds transferred to new departments of Development Assistance and of Nautral Resources, the proposed new name for the Interior Department.

Experts said the dozens of development and housing programs now located in five agencies are fragmented, have conflicting requirements and goals, and impede effective planning at both the national and local level.

The developement study, headed by Lester Salamon, ureged that all the programs be moved to an expanded Department of Housing and Urban Development that would be renamed the Department of Development Assistance.

Salamon, a Duke University professor on leave to OMB as a deputy associate director, recommended that the new department include the Agriculture Department's rural community and economic development programs, Commerce's Economic Development Administration, the economic development programs of both the Community Services Administration and the Small Business Administration.

All HUD programs would stay in the renamed, expanded agency.

If the proposed agency existed today, it would have authority to make laons and grants totaling $37.8 billion in fiscal 1979, actually would spend $10.4 billion and would have about 18,000 employes.

That would make it the seventh-biggest Cabinet agency in terms of budget and the smallest in terms of manpower.

The study said that by putting in one department all responsibility for development and housing - from the approval of grants and loans for projects t obroad planning for development in urban and rural areas - the inconsistencies and frustrations involved in trying to eliminate poverty and upgrade the economic base of the country could be minimized.

For examply, the study told how the small town of Junior, W.Va., was ordered by the Einvironmental Protection Agency in 1970 to build a new sewage treatment and collection system.

The federl aid - from planning to construction - was scattered among five agencies. Each had its own requiements, assistance levls and forms.

"Altogether," the study said, "the effort to secure funding for this one project took seven years and left behind a residue of forms, applications, plans, correspondence and related documents that now fills an entire room in the office of the town lawyer. During this period, moreover, the cost of the project jumped by 144 percent."

Smaller communities have long complained that, because they are unable to maintain big development staffs, they miss out on many programs or can't meet the requirements. Boston maintains a full-time Federal Programs Office that costs the city $1 million a year.

The new federal department would not only become a "one-stop shopping" agency, but also would be better able to package programs to provide the most for the money.

Streamlined programs and decision-making also would facilitate private participation in development efforts, the study said.

Now if, for example, a city wants to rebuild an area with housing, public facilities and industry, delay or refusal by one of the many federal agencies involved can suttle the project. Private industries are reluctant to locate in such an area because of the red tape, delay and risk that one or another agency will withhold key funding.

Such a streamlined department also would reduce overlapping research and planning by the five economic development agencies and would be better able to anticipate and deal with long-range deveopment issues.

The proposed Department of Natural Resources would include all agencies and functions of the Interior Department except for the Bureau of Reclamation's water project construction, which would go to the Army Corps of Engineers.

But the Corps - which does both civilian and military construction - would lose its role in planning and authorizing civilian civil works projects and would function mainly as the building arm of the new Cabinet department.

Similiarly the Agriculture Department's Forest Service and Soil Conservation Service would be transferred to the new department, as would Commerce's National Oceanic and Atmospheric Administration.

This study, directed by William Harsch, said that by consolidating all natural resource planning and management the government would be better able to:

Manage all natural resources, for which no agency now has total responsibility or accountability.

Balance conflicting commercial and conservation interests in the nation's forests, rivers, lakes and offshore drilling areas.

Do better research and save millions of dollars by eliminating overlapping functions and personnel.

If the department existed today it would have budget authority of $10.1 billion and 88,200 employes.