Nutrient status, water consumption and productivity of grain sorghum in the southern part of the Rostov region depending on sowing dates and seeding rates

Sorghum is a drought-resistant, heat-loving crop, the grain of which is highly nutritious and widely used in animal husbandry. In the Russian Federation, the Rostov Region ranks first in terms of sowing areas for this crop. The purpose of the current study was to determine the effect of seeding rates and sowing dates of grain sorghum on productivity, water consumption and nutrient status in the southern part of the Rostov Region. The study was conducted at the FSBSI “ARC “Donskoy” in 2022–2023. As a result of the study, there has been found a decrease of grain nitrogen available to sorghum plants to 4.1–4.7; 4.1-4.9 and 4.2–4.7 mg/kg of soil for the varieties ‘Zernogradskoye 88’, ‘Ataman’ and ‘Esaul’, respectively. By the complete maturity stage, the mobile phosphorus content in soil decreased to 15.3–17.0; 16.0–17.0; 14.1–15.7 mg/kg of soil, respectively, for the varieties ‘Zernogradskoe 88’, ‘Ataman’, and ‘Esaul’. At the end of grain sorghum vegetation period, the exchangeable potassium content was at the level of 271–306; 275–295; 261–290 mg/kg of soil, respectively, for the varieties ‘Zernogradskoe 88’, ‘Ataman’, and ‘Esaul’. Water consumption was at the level of 227.4–277.9 mm/ha for the variety ‘Zernogradskoye 88’, 219.6–272.1 mm/ha for the variety ‘Ataman’ and 222.8–271.5 mm/ha for the variety ‘Esaul’. At the same time, moisture consumption for the formation of grain productivity was 48.42–70.41; 42.92–69.85; 47.15–83.70 mm/t, respectively, for the varieties ‘Zernogradskoye 88’, ‘Ataman’, and ‘Esaul’. Over the years of study, the mean grain productivity was 4.51 t/ha for the variety ‘Zernogradskoye 88’, 4.66 t/ha for the variety ‘Ataman’, 4.11 t/ha for the variety ‘Esaul’. The largest productivity was identified in the third sowing date (4.66 t/ha on average according to a sowing date) and at a seeding rate of 0.4 million germ. pcs. per ha (4.94 t/ha on average according to a seeding rate).