To begin with, there was no "farmers" in Russia or Soviet Union until 1990s.
And for most of population, agriculture was not a "profession", but social status, "class" as it was called.
These people were called peasants. If you are born into a peasant family, you are a peasant, by default. Peasants were a "class", not a profession.
In different times it was more difficult or less difficult
to move to a city, or to obtain some other social status, by education, for example.
In the period we are talking about, peasant lived on the land which was owned by the state. They possessed plots but these plots could not be bought or sold.
They had plots which they developed. Sometimes it was possible to escape to the city (without any of your property) and find work there, and place to live.
Still in the beginning of the Soviet state, most peasants had individual plots,
and could sell their product on the market.
In the process of collectivization, in the early 1930s, these plots were united
to large collective farms. Their production was simply taken by the state. This led to a large and widespread famine.
During the famine, the movement from the country to cities was blocked by the police and troops. Moreover, during the Stalin rule, internal passports were introduced for all except peasants. One could not legally travel or live
in a city without a passport. This changed only in 1960 when peasant obtained passports.
Shortly speaking, agriculture was not a profession, and perhaps the most unsafe "occupation". Peasants were just deprived of all means of existence, and for most of them there was no way out. Many of them died of starvation.