A dessiatin or desyatina (Russian: десятина) is an archaic, rudimentary land measurement used in tsarist Russia. A dessiatin is equal to 2,400 square sazhens and is approximately equivalent to 2.702 English acres or, precisely, 10,925.397 504 square metres (1.09 hectare).
Hence 3 proprietor's desyatinas = 4 official desyatinas.