Impact of irrigation, surface residue cover and plant population on sugarbeet growth and yield, irrigation water use efficiency and soil water dynamics

Currently, sugarbeet producers in western Nebraska are facing the challenge of reducing their irrigation water usage due to ground water pumping restrictions and the unpredictable amount of rainfall that is available from year to year. Therefore, there is an increasing interest in developing season long deficit irrigation strategies for sugarbeet, the main objective of this study. The other objectives were to determine the impact of surface residue and plant population on sugarbeet production. Three field trials were conducted in eight consecutive cropping seasons (2008-2015). The average root and sugar yield for the full irrigation treatment were equal to 71.11 and 11.08 Mg ha−1, respectively during the 6 years of the two irrigation studies (2008-2013) while applying 75% and 50% ETc on average caused 9% and 11% yield reduction, respectively (2008-2011). Plots under full irrigation treatment and rainfed showed highest and lowest water depletion, respectively. Overall based on six years of data (2008-2013), stressing moderate and severe late in growing season produced 1.03 and 1.87 Mg ha−1 more sugar while consuming about 13 mm less water than imposing same level of stress early in season. The residue covered plots produced 0.29 Mg ha−1 more sugar yield than bare soil plots on average across treatments and years. Overall, higher population rates resulted in higher sugarbeet yield. Findings of this research will deliver insight for sugarbeet irrigation management.