Green - arable land, red - abandoned arable land. (to bring it into scale - total abandoned arable land in Russia is bigger than entire Germany, 39 mln hectares)
another version, with Central Asia included
Why the abandonment? And is said land reclaimable for agriculture?
during soviet era due to plan economy and to write up good reports, all sorts of place were ploughed up. some of it was useful, some not. my late father-of-law was tractor operator in collective farm and wife remebers still how she looked at dad working on some hillside and wondering when will the tractor tilt over and fell on dad. as soon as soviet order crashed, such fields-´´fields´´ were abandoned.
besides that every decent collective farm director had secret fields that were not counted officially, crops of which were added to regulars, hence being able to claim higher average yields etc.