October 16, 1982

President Reagan announced today that the United States had offered to sell 23 million tons of grain this year to the Soviet Union, a quantity nearly three times greater than the amount provided for under an existing sales agreement between the two countries. If the Russians agreed during November to buy the full amount, Mr. Reagan said in a radio address broadcast over several farm-state stations, he would guarantee for the next six months that deliveries would not be interrupted by any American embargo that might arise out of subsequent differences between the two countries. In his address, Mr. Reagan also threatened ''strong measures'' to counter the ''growing tide of protectionism and export subsidies overseas.'' The delivery guarantee on the grain appeared to be the first ever. But some farm organizations said the time limit implied that the President had not ruled out a future embargo of shipments to the Soviet Union.

At the age of 42, J.B. Grothaus is as trim and lean as a college athlete, a condition he attributes to his Spartan struggle to survive for the last three years on 237 acres of prime farmland. The 16-hour work days, he says, are the easy part. The discoveries he makes over his books at night are the most painful. After careful computations, he recently found that the corn he was feeding his hogs had cost more to grow than it would have cost to buy at the grain elevator down the road. The tractor tire that cost him $489 in 1974 now goes for $1,775, while his soybeans bring half of what they did then. Mr. Grothaus is not alone. Among the various occupational groups, people who earn their living on farms around the United States have suffered the greatest decline in income in recent years, according to Census Bureau figures.

To help avoid repetition of the seven Chicago area deaths from Tylenol capsules laced with cyanide, the Food and Drug Administration has quietly begun to design a system for rapid reporting of poison deaths. Federal officials must now wait as long as three years to see national statistics on poison deaths. Even then, the statistical categories are so broad that the pattern of the seven deaths from the popular pain reliever would not have been apparent. ''It's amazing to think that up-to-date national figures on poison deaths are unavailable anywhere, but it's true,'' said Dr. Mark I. Fow, director of the agency's poison control center.

Industrial production fell again in September, indicating that the recession may not have ended, while the principal index of producer prices slipped, signaling more relief from inflation, the Government reported today. The reports were the last broad-gauge statistics on the performance of the economy in September to be released before the Nov. 2 election and could provide fuel for both Republicans and Democrats. The declines in factory output and producer prices were signs of the weakness in the economy that has lifted unemployment above 10 percent, a campaign theme for the Democrats. A Slowdown of Inflation But the price index also showed a slowdown of inflation, something President Reagan has stressed in campaign speeches on behalf of Republican candidates for Congress.

The United States has raised objections to an Israeli proposal that Palestine Liberation Organization forces leave Lebanon before other foreign troops, State Department officials said today. The officials said that in the detailed discussions about Lebanon held on Thursday by Secretary of State George P. Shultz, Foreign Minister Yitzhak Shamir of Israel and their aides, some specific problems arose that would probably take some time to resolve. But American officials, as well as Mr. Shamir, stressed that the talks were free of polemics and that they were useful as a first round of negotiations on bringing about the withdrawal of all Israeli, Syrian and P.L.O. forces from Lebanon. An Unofficial Intermediary The United States, which is acting as an unofficial intermediary between Israel, Lebanon and Syria, has avoided presenting the Israelis with a detailed American plan, pending talks next Tuesday between President Reagan and President Amin Gemayel of Lebanon, officials said.