With the exception of the black earth belt, Russia has fairly poor soil, a short growing season, low precipitation, and large arid steppe regions unfit for agriculture except with extensive irrigation.
Below that, the relatively arid steppe, with grasslands and semidesert and desert regions, runs along the northern edge of the Caucasus Mountains and north of the Caspian Sea beyond the Volga River basin into Central Asia.
People ethnically identified as Russians have been politically and culturally dominant in a vast area for five hundred years of tsarist and Soviet imperial expansion.
However, despite repression of their cultural autonomy, minority cultures have survived within the Russian Federation; including the peoples of the North Caucasus, numerous indigenous groups in Siberia, the Tatars in the Volga region, and the East Slavic Ukrainians and Belorusians.
Some scholars believe this to have been a Varangian (Viking) clan from Scandinavia, and others hold that it was a Slavic tribe.
Some historians believe that "Rus" derives from an ancient name for the Volga River.