Lucerne, a high-yielding, multi-cut legume, offers consistent forage yields and high protein content under arid conditions. In southern Russia's arid zone, where natural hayfields are highly weather-dependent, lucerne provides a stable and sustainable alternative. This study examines how agrometeorological factors affect lucerne crop formation to support optimised cultivation in the Volgograd region. This research was conducted at the experimental production field of the Scientific Research Center of Agroecology of the Russian Academy of Sciences in the period 2022 to 2024. The field experiment was conducted on light chestnut heavy loamy brackish soils. The field experiment, recordings, analyses and statistical processing were carried out by the methodology of field and agrotechnical research with forage crops. The study established that soil moisture is the main factor determining the yield of hay and lucerne seeds. It is revealed that an important role in the formation of yields is played by moistening during the period of maximum growth, during the branching phase. This period lasts for three decades from the beginning of regrowth to the end of May; the correlation coefficient was r=0.88. In years with average moisture during the growing season, there are two maxima of linear and weight gain in the branching phase and the budding phase. The stress of meteorological conditions during the budding phase reduces the growth energy and the final yield of hay. In the territory under consideration, the average yield of lucerne hay is 1.74 t/ha with annual fluctuations from 1.3 to 3.0 t/ha.