Agriculture Secretary Richard Lyng on Friday described this summer's drought as "very, very serious" and said President Reagan was "tremendously interested" in the situation. But he repeated earlier statements that it was too early to talk about what kind of federal aid might be forthcoming.

At the White House, officials said it was likely the president would visit a drought-stricken area during a trip to Davenport, Iowa, on July 14.Lyng, speaking with reporters after giving Reagan a preliminary report from the Interagency Drought Policy Committee, predicted that the drought would raise retail food prices an additional 1 percent this year - and perhaps as much as 2 percent next year.

Asked if he still held out hope for salvaging this year's crops, Lyng said, "We still have the month of July. . . . If we should get a couple inches of rain a week through the month of July in Midwest corn fields, we'd get a pretty good corn crop. . . . We conceivably could get an 80 percent crop, or even 85 overall."

At the same time, Lyng noted, that kind of rainfall was not in the long-range forecast. "If you look at the 30-day forecast, or the 6-to-10-day forecast," he said, "the prospects are bleak."

In describing his meeting with the president, Lyng said Reagan was "tremendously interested and shows a great deal of care and concern about the effects of (he drought). . . . He has a great deal of interest and concern and compassion for people in the corn belt, and he remembers his days in Illinois."

Asked what kind of federal assistance might be planned, Lyng replied: "To get into writing checks to farmers for relief to help them, tide them over, almost needs to await the normal harvest period so that they can compare what they are harvesting, what happened to them - and you just can't do that on the 1st of July.

"That crop is still growing and still there, in most cases, and the relief will not be needed until they would normally have the crop and have it ready for sale," the agriculture secretary said. "At that time, we should be standing there ready to help them."

Lyng said he and Reagan both believe that any kind of future payments to farmers must first be worked out with Congress "and we prefer to do it, if we can, on a bicameral, bipartisan basis."

"For us to propose details on that would be trying to take a lead role that would not be conducive to the kind of solution that would be responsive to the needs of those farmers. So we talked about this bipartisan effort, but we did not go into details on means of doing it," he said of his talks with the president.