It is heartening to see that the United States and the Soviet Union can do business. Poland, Afghanistan, Central America, and other hot spots notwithstanding, the superpowers are capable of getting together in areas where they have a mutual interest in cooperation. Trade is one of them. A new grain agreement commits the Russians to buying at least nine million metric tons of US grain in each of the next five years. The Russians are happy, American farmers are happy, and - while this does not eliminate all the knotty problems in US-Soviet relations - it is an important, positive step.
Domestic considerations seem to have played the overriding role on both sides. President Reagan was faced with American farmers pleading to do something in the face of mounting grain surpluses. His PIK program to reduce production and alleviate government storage costs has had mixed results. Farmers have taken land out of production, to be sure, but it has largely been marginal land. Being the shrewd businessmen they are, they kept the best land in use and actually worked it harder than normal. So, overall, grain output has not declined as much as expected. Selling to the Russians has looked better and better as a way out of the dilemma of American farm efficiency.
This of course required some fast footwork on the President's part. Mr. Reagan, as part of his policy of economic sanctions against Poland, had refused to negotiate a new grain agreement with Moscow. He simply renewed the old one - twice. But domestic pressures were building and he bent to a more practical, pragmatic course.
So much for economic sanctions. In the process or reversing course, however, his negotiators managed to strike a good deal - requiring the Russians to purchase 50 percent more each year than under the old accord. The required minimum purchases from the US will now constitute about 30 percent of the USSR's total grain imports.
And what of Yuri Andropov? Let it be said first that Americans are not saving Soviet agriculture. The Russians in fact expect a good grain harvest this year - over 200 million metric tons as compared with 180 million tons in 1982. The imported grain, moreover, is for the purpose of building up their livestock herds, not feeding people. The fact is, the Russians like to cover all bases in such an unpredictable area as agriculture. While they can import plenty of grain from Canada, Australia, and other countries, it clearly is to their advantage to be able to count on a single supplier. Especially given their cumbersome long-term planning system.
Perhaps there is a political nuance in all this as well. There have been a number of signs of late that Mr. Andropov is prepared to improve US-Soviet relations. These signs - release of the Pentacostals, a softer position in the Madrid security conference, and others - seem to be saying that Moscow is willing to deal with the Reagan administration if the latter responds accordingly. Such ''reasonableness'' has its reverberations on public opinion in Western Europe, where the Russians are trying to stave off the deployment of new NATO missiles. Does Mr. Andropov calculate that, if deployment does go ahead and he is forced to respond in some way, he can escape being blamed for a worsening of East-West relations inasmuch as he tried so visibly to come to terms?
No one can be sure. In general the Russians' basic approach is to keep economic policy separated from politics. The grain agreement is good economics. In any case, the world can always breathe a little more easily when the nuclear giants are trading with each other - not exchanging bullets.