The fertile characteristics of soils of Svetlinskyi district of Orenburg region have been analyzed in the paper. Using the Karmanov technique the qualitative estimation of soils was carried out, the soil ecological index (SEI) for each soil difference was estimated and all soils were grouped in accordance with their fertile characteristics. The estimation has shown that soils of Svetlinskyi district are low-potential. There is no any chernozem soil within the district territory. Soils with SEI of 15 to 25 points constitute the major part of the district territory (about 62.06%), for these soils using the adapted landscape or transferring them to fallow lands are recommended. An arable land stock is insignificant ( SEI is above 25 points), its contains just 7.01% of the total district territory. An area of nonarable lands is rather large (25.44%), among which there are two low-potential land massives. In the vicinity of one of them there are several pieces of water. The territory of the land massive has at its disposal favourable climate conditions for life activity of the endangered population of saiga antelopes. At present study, the expedience of transforming these lands to specially protected natural areas (SPNAs) to create on their base a zoological reserve for reintroduction of saiga antelopes is discussed.