The Soviet Union today indicated disapproval of Poland's agreement to recognize a new union for farmers and continued to publicly ignore the rapidly growing reform movement within the Polish Communist Party.

In a brief Warsaw dispatch, the official Tass press agency reported that the government has agreed to the certification of the union for Poland's 3.5 million private farmers, a major concession that Moscow cannot find to its liking. The carefully worded dispatch implied that the Polish government was only agreeing to the legal status for the union, generally known as Rural Solidarity, as a continuation of its attempts three weeks ago to head off a crippling national strike.

Noting that the official Polish news agency PAP had "transmitted a statement by the Polish government," Tass said that "from the statement it follows that an agreement was signed on March 30. Under the agreement, the founding of a trade union of individual peasants is now recognized."

Tass ought to salvage something for its Soviet public, which belongs to unions strictly subordinated to party control, by adding that the agreement included a statement by farmers' union activists "which recognizes the role of the Polish Communist Party as the guiding force in the building of socialism."

Seen from here, this formulation leaves Moscow open to claim at some later date, if it wishes, that either the party under Stanislaw Kania's direction failed to preserve its position as "guiding force," or that the agreement was coerced from the authorities by the independent trade union federation Solidarity under threat of a strike. Tass did not report yesterday's agreement in Bydgoszcz for the rural union to be registered by May 10.

Meanwhile, the Kremlin's spokesman Leonid Zamyatin tonight spoke on Soviet television of increased counterrevolution in Poland and asserted that the Soviet Union would not abandon "fraternal socialist Poland in its hour of need." He scathingly attacked by name leaders of the Polish Committee for Social Self-Defense, KOR.

Zamyatin's 15-minute public discussion of Poland was one of the longest made by any Soviet official since the Polish labor unrest began in August. Western diplomats here saw his television appearance as directly reflecting the gravity with which Moscow regards the situation in Poland.

His comments followed the pattern of other high-level Soviet statements on Poland, expressing apparent confidence in the Polish leadership without ruling out the possibility of intervention.

While Soviet propaganda against Solidarity continues with almost daily denunciations of its alleged ties to Western "counterrevolutionaries," the media here have said nothing about the mass meeting in Torun at midweek in which delegates called for democratization of the party. The internal ferment and steady incorporation of liberalizing changes into the Polish party's life seems to have caught Moscow off-guard after the tensions of three weeks ago.

So far, the Polish Communists show no sign of being able to stem the reform, and Moscow has yet to formulate any discernible approach to this short of the ever-present possibility of toppling Kania from power or direct armed intervention.