Soybean varieties responsiveness to irrigation in the of Western Siberia steppe

The purpose of research is to study the responsiveness of soybean varieties bred at the Omsk ANC to optimize the conditions of moisture and mineral nutrition of the soil in the arid conditions of the steppe of the Omsk Region. The experiments were carried out in 2019 and 2020 on two backgrounds (non-irrigated - rainfed and irrigated) in the SPK Cherlaksky Fruit Nursery in the Omsk Region. The soil of the plot is southern light loamy chernozem, the humus content in the arable layer is 3.1 %, pH = 7.2. The field experiment was implemented by superimposing soybean varieties recommended for cultivation in the 10th region (Sibiryachka, Eldorado, Zolotistaya, Cheremshanka) on mineral nutrition options: control - without fertilizers; N30; N60; P60; N30P60; N60P60. The analysis of the main elements of the crop structure, yield and quality of seeds was carried out. Weather conditions were dry and did not fully meet the biological needs of soybeans. The varietal specificity of soybean responsiveness to changing growing conditions was revealed. The Eldorado variety was the most drought-resistant and, on average, on rainfed crops, the most productive (1.49 t/ha) with a maximum of 1.69 t/ha against the background of N30P60 (an increase to the Sibiryachka standard is 0.67 and 0.85 t/ha, respectively). Under irrigation conditions, Sibiryachka soybean showed the maximum result in the experiment of 2.92 t/ha in the N60P60 variant, the second with a lag of 0.36 t/ha was the Eldorado variety in the N60 variant. An increase in the protein content of seeds on a fertilized background in comparison with the control was revealed: on a rainfed land - by 4.5 %; under irrigation - by 4.9 % and a decrease in oil content by 2.0 and 2.6 %, respectively. On a fertilized background, the maximum protein content in the grain was shown: on the rainfed land, the Zolotistaya variety - 38 %; on irrigation, the Cheremshanka variety - 40 %. Under irrigation against an unfertilized background, the varieties Sibiryachka, Cheremshanka, and especially Eldorado were highly oily with the maximum fat content in seeds in the experiment - 23 %.