The purpose of the research was the analysis of the effi-ciency of development of virgin and fallow lands in XX and at the beginning of the XXI century in the Republic of Khakassia, its influence on making agricultural production, manifestation and development of erosive processes. The dynamics of cultivated areas of crops and gross collecting grain were de-termined by the data of reports of the Ministry of Agriculture and Food of the Republic of Khakassia. The periods of the greatest development of virgin and fallow lands, cultivated areas of crops and manifestation of erosive processes were revealed at due time. Performing the researches statistical and graphic methods of the analysis were applied. The results of the researches showed that in the steppe zone of the Re-public of Khakassia located in the south of Central Siberia three periods of mass development of virgin and lay lands having positive and negative consequences were noted. The development of new lands in the first period (1930-1940) led to the increase in cultivated areas of crops and soils degrada-tion, in the second period (1954-1963) the conditions of pub-lic property promoted the increase in gross production by 2.1 times, the manifestation and the strongest development of erosive processes. The third modern period (at the beginning of the XXI century - 2006-2017) their development in the conditions of private property was marked by the arrival of unprepared staff (land users, farmers), the lack of antierosion equipment and the beginning of manifestation of wind ero-sion. Potential danger of degradation of soils is very high. Urgent measures for protection of soils against erosion are necessary, and the training of qualified specialists for this purpose is required.