The main reason was Lenin’s continued policy of grain requisitioning. Peasants had been used to maintaining stocks to see themselves through times of bad harvests. Now they grew just enough for subsistence, to feed their livestock and to keep sufficient seed to sow the next harvest. What was the point of producing more if the Bolsheviks took it all? By 1920 the sown area of the Volga region had declined by 25 per cent in three years. When a poor harvest came there were no reserves of stock.

Victor Sebestyen, Lenin: The man, the dictator, and the master of terror, New York, 2017, p. 480