Agriculture Secretary Bob Bergland warned yesterday that American agriculture "is on a collision course with disaster" because overly intensive production is eroding land and drying up cital water supplies.

Appearing on "Face the Nation" (CBS, WDVX), Bergland said he has ordered a eview of Agriculture Department politics to determine what should be done to salt the trend.

He blamed the depletion of land and water on "a set of very bad habits" developed by American farmers at record highs, encouraging farmers to increase their production by, for example, planning on "marginal land."

"Some of those bad habits have held over," he said.

Bergland forecast a 7 percent increase in food prices next year, most of it because of an increase in packaging costs and a "modest increase" in the cost of beef. But he conceded that this forecast could be too low because of factors such as weather.

Bergland, who recently returned from a strip to China, said increased sales of American feed grains to China will have "no noticeable impact on the consumer price index" in the United States. He predicted the amount exported to China next year will be 5 million to 6 million tons, slightly higher than this year's sales.

Bergland said the Chinese are less interested in buying grain from the United States than they are in acquiring agriculture technology such as food-processing plants. The lack of formal diplomatic ties between the two countries "tends to complicate matters."he said, but it has not put the United States at a disadvantage with other nations competing to trade with the Chinese.

On other topics, Bergland:STSaid the Agriculture Department has found no evidence that wholesale suppliers are increasing prices to food stores in anticipation of wage and price controls.

Acknowledged that "some changes are in order" because of overlapping government functions, such as similar programs run to the Agriculture and INterior departments.

Estimated that about 5 million acres of the 1 bilion privately controlled acres of farmland in he United States is owned by foreign investors. He said USDA will complete a survey of foreign ownership of farmlands next year, but the amount is not considered substantial.

Said this year's elections showed that both farmers and consumers support administration policies. "There was no farm revolt by any stretch of the imagination," he said.

Another administration official, Leonel J. Castillo, Immigration and Naturalization Service commissioner who appeared on "Meet the Press" (NBC, EBC) yesterday, defended himself against internal critism in his agency and called for a change in U.S. immigration laws.

Castillo said the law should be changed to allow for the farm of "amnesty" for illegal aliens who have been in the United States for a number of years. He said he also favors legislation to penalize employers who consistently hire illegal aliens.

Castillo has been criticized by some INS officials for being overly sympathetic to the plight of aliens at the expense of government efforts to enforce immigration laws. He denied this yesterday and said the record number of illegal aliens apprehended along of Mexican border the past two years shows INS in enforcing the law.

Castillo blamed the criticism on "frustration" among some agency officials because of budget constraints that are likely to become tighter under the administration's anti-inflation program.

Castillo also defended a plan to construct two new fences along the U.S. Mexican border at El Paso and San Diego to make it more difficult for illegal aliens to enter the United States. But he conceded that the original design "was a mistake," because the fences envisioned could have seriously injured people seeking to scale them. The design brought a strong protest from the Mexican government.

"We do want the fence to deter entry . . . We don't want to maim people," he said.