Improving quantity and quality of sugar beet yield using agronomic methods in summer cultivation

The effect of agronomic factors on the amount of water consumption and its productivity in arid and semiarid regions is very important. This study was conducted to diagnose agronomical procedures for increasing the yield and water productivity of sugar beet in two years (2016 and 2017). The experimental factors were: sowing date (spring and summer), planting arrangement (25–50 cm and 40–50 cm, double rows with a distance of 25 cm or 40 cm and a distance between each double row of 50 cm), and plant density (90, 120 and 160 thousand plant/ha). In the second year, the harvesting date, which consisted of conventional (October) and delayed (November), was added to the experiment. High temperature during and immediately after planting decreased emergence on the summer sowing date. The uniformity of roots and irrigation water productivity (WPirrig) in spring crops was higher than those of summer crops; meanwhile, on the summer sowing date, water consumption declined by 27% (and the sugar yield decreased intensively by 44%). Furthermore, planting arrangements of 25–50 resulted in better plant establishment and eventually increased the number of final plants. Besides, increasing plant density improved the uniformity of plants root. Sowing in summer compared to spring reduced root and sugar yield on a conventional harvesting date by about 40%. After 25 days’ delay in harvesting time on both sowing dates (by mean), root yield, sugar yield, and WPirrig, increased by about 14, 28 and 22%, respectively. In general, at moderate densities (about 120 000), planting arrangement 40–50 and at low densities (less than 90 000, which usually occurs on the summer sowing date), planting arrangement 25–50 is recommended to increase yield and WPirrig.