What was going on when I was born?

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.

Lurking in the background of a major civil rights case before the Supreme Court is an issue of broad concern to hundreds of nonprofit religious, charitable and other groups that shun the racial discrimination practiced by the two private schools in the case. The question is whether the exemptions from taxation that almost all such nonprofit groups enjoy should be treated as the legal equivalent of direct Government subsidies, as some civil rights groups have argued before the Court. If so, all private tax-exempt groups could come under the complex web of regulations and legal obligations that accompany direct Government subsidies, including rules against discrimination on grounds of sex, religion, handicap and age, as well as race. Possible Repercussions This could possibly affect all-boy and all-girl private schools, retirement homes operated by religious charities for people of particular creeds, churches that refuse to ordain women as priests or ministers and community centers serving particular ethnic groups.

The United Automobile Workers went back to the Chrysler Corporation today in the hope of winning an immediate pay increase that would satisfy the huge majority of the rank and file that rejected the union's last contract proposal. Douglas A. Fraser, the union president, and his bargaining team spent three hours at Chrysler headquarters this morning presenting the union's demand for an hourly wage increase that he said clearly lay behind the first rank-and-file rejection of a proposed contract at one of the country's major automakers. The new round of negotiations should be ended by next Friday ''one way or the other,'' Mr. Fraser said, conceding that ''the other'' meant at least the contemplation of a strike against Chrysler, which is in fragile financial shape after coming to the brink of insolvency. A final tally showed that more than 70 percent of the company's hourly workers voted against the proposed contract. It had allowed for gradual cost-of-living adjustments but did not recover any of the hourly wage increases the union has forgone for the last two and a half years of Chrysler's financial difficulties.

A convict under siege at Kings County Hospital Center in Brooklyn released a fourth hostage unharmed yesterday afternoon, but continued to hold a fifth man at gunpoint early today in a dingy basement locker room that was surrounded by scores of heavily armed police officers. Last night, 36 hours after the ordeal began, the gunman demanded live air time on five New York television channels. He hinted that he intended to kill himself on the air, and threatened to ''play Russian roulette'' with his last hostage, Elton Smith, if he did not get the air time. ''This man's life is in your hands,'' the gunman, 33-year-old Larry Van Dyke, told police hostage negotiators. It was not clear how the police would respond. Radio and television interviews had earlier been exchanged for hostages as the news media's traditional role of observer grew increasingly into that of a participant in the drama.

The Foreign Minister of Nicaragua told the General Assembly today that his country ''desired an understanding'' with the United States but that ''the response of the U.S. Government has been to attempt to impose on us its rigid East-West outlook.'' The Rev. Miguel D'Escoto Brockmann, the Foreign Minister, accused the Reagan Administration of ''financing covert destabilizing activities'' and ''the use of its territory for the training of counterrevolutionaries.'' Father d'Escoto described American nuclear strategy as ''reckless,'' ''denounced the campaign launched by the Reagan Administration to deprive Angola of its inalienable rights'' and condemned ''great power complicity'' in Israel's invasion of Lebanon. Reply From U.S. Kenneth L. Adelman, the United States permanent representative, exercising the right of reply, said that the United States was being subjected ''to the same baseless allegations'' that it is an aggressor.

So far as the public is concerned, the annual session of the United Nations General Assembly is an opportunity for ministers of some 130 countries to come to New York, deliver a pro forma speech to an almost empty chamber, drop in on a few parties and go home. ''Not quite,'' said Suppiah Dhanabalan, the Foreign Minister of Singapore. ''If that's all it was I could find many better things to do with the time.'' The speeches, which began on Sept. 27, are almost entirely for home consumption. They are well planned and carefully written because they are covered exhaustively in the speakers' home countries. But here in New York, the speeches, except for those of the United States and the Soviet Union, are mostly window dressing for the real work of this gathering, which is to afford the foreign ministers of the world an opportunity to see each other on a relatively informal basis.

President Gustav Husak will visit Austria next month, the first such visit by a Czechoslovak head of state, it was announced today. Mr. Husak was to have visited Austria last year, but the trip was put off after it was revealed that a Czechoslovak intelligence agent had lived in Vienna, with Austrian citizenship, posing as a political refugee.

President Francois Mitterrand, commenting on a report that France had told some allied officials it would build a neutron weapon, said today that the ''moment has not come.'' Replying to reporters' questions, Mr. Mitterrand said: ''I have given the order to continue studies so as to place us in a situation to immediately build a neutron bomb, if I make the decision. But the moment has not come. We have other priorities in armaments.''