From Stephen Kotkin’s new Stalin:

Peasant expectations of a total land redistribution were intense, and the wartime tsarist government had helped spur them, confiscating land from ethnic Germans living in imperial Russia, which was supposed to be redistributed to valiant Russia soldiers or landless peasants. The army, on its own, promised free land to winners of medals, spurring rumors that all soldiers would receive land at the war’s end.  Total tsarist government confiscations of agricultural land during the war – which was seized with minimal or zero compensation from some of the empire’s most productive farmers, and contributed to the severe shortage of grain in 1916 and the bread riots in 1917 – amounted to at least 15 million acres.

From context, 15 million acres seems to be roughly 15% of contemporary Russian farmland.  I’ve long known about the many continuities between czarist and Bolshevik policy, but I never before heard that the last Czar of Russia spear-headed massive expropriation of farmers whose only “crime” was membership in a successful outgroup.