The author of the article, on the basis of archival documents and scientific and historical sources, studies the history of the beginning of irrigation and land development in Central Fergana in the 40-50s of the 20th century. In the studied period, the Fergana Valley was the main cotton-growing base and the developed territory in historical sources was called Karakalpak Steppe. The article also lists the reasons for a sharp deterioration in the land reclamation state of the Fergana Valley due to an increase in salinity, since the extensive path of development of the agricultural sector by the Soviet government during the study period was based on quantitative results