Yield of soybean cultivars at irrigation in the dry steppe zone of the Volga region

The purpose of this research was to develop norms and dates of irrigation on the experimental soybean crops in the dry steppe zone of the Volga region. Developed irrigation ensures to obtain a favorable water balance during the whole season of crop growth. The optimum mode of irrigation on a scheme of soil moistening 70-80-70% of nominal moistening (NM) was selected. Features of irrigation norms and dates for released soybean cultivars were revealed. Irrigation regime depends on a zone, soil and hydrological and weather conditions, method and techniques. Due to the prevailing weather conditions of spring, presowing or provocative irrigation with norm of 250300 m3 per ha may be conducted. Then vegetative waterings are assigned, those are adapted to water-consumption phases of crop development. There was determined biological yield of released soybean cultivars produced under optimal irrigation on soil moistening 70-80-70% of NM. Biological yield of soybean cultivars released in the Low Volga region from the State register of breeding achievements (Amphor, Arleta, Gratsiya, Soer-4) was up to 3.5 t per ha that characterizing all these cultivars as highly productive. The protein content in all cultivars ranged from 36.7 to 41.0% that characterizing their seeds as highly protein and fat contents is from 16.9 to 20.1 %. The irrigation norms in the dry steppe zone of the Volga region depend on a year conditions: in wet year they are 800-1300 м3 per ha, in temperate dry year -1300-2700 м3 per ha.