Outer Manchuria was known as Green Ukraine.Russia occupied Manchuria after kicking out the Japanese army in 1945. No idea where you get the idea Ukranians were sent there to 'colonise' the region.
"Russian" was a generic term for all sorts of ethnic groups who colonised Manchuria.
A lot of so called Russian settlers were actually Ukrainian.
Ukrainians in Manchuria, China:
A Concise Historical Survey
Serge Cipko
ABSTRACT: There is a body ofliterature that attests to Russian influence in the
early development of Harbin, China, Edmonton's twin city, and northern
Manchuria generally. What is not acknowledged in this literature, howevet, is
that the "Russian" presence in Manchuria drew on considerable Ukrainian
participation. This article explains why scholars of Manchuria have tended to
refer to the settlers from the European parts of the Russian Empire only as
"Russians" rather than distinguishing them according to their real national
compartments. Then, by drawing on little known sources, an examination ofthe
background to Ukrainian settlement in the region, the evolution ofthe community
there, and the emergence ofseparate Ukrainian organizations, follows.