Precipitation and yield of spring wheat in the semiarid zone of Orenburg Cis-Urals

Abstract

Spring wheat is produced in Orenburg Cis-Urals in conditions of moisture deficiency. Among 69 years studied (1951-2019), 16 turned out to be dry, 25-arid, with a total precipitation of less than 380 mm. In terms of precipitation during the growing season 50 years were dry and arid, a total was less than 130 mm. According to the annual amount of precipitation, a cyclicality was established with alternation of two humid decades with one dry one. In support of the hypothesis, precipitation in the first half of the growing season of wheat is dominant, and the least in the second of all categories. Significant relationships were established between them and the yield, r = 0.814 and r = 0.574. Annual moisture resources have a weaker relationship with yield (r = 0.566) than precipitation during the growing season (r = 0.730). The surge in yield due to precipitation in the first half of the growing season of wheat is its response to the moistening of the upper soil layer during tillering and the formation of a secondary root system. Hence, the main requirement for the technology of growing spring wheat is to moisten the top 0-5 cm of the soil layer in the tillering phase to 17% of the mass of dry soil and above.