Yield and Quality of Sugarbeet As Influenced By Nitrogen Supply and Tillage System Under Sprinkler Irrigation in Big Horn Basin Wyoming.

Tillage system and nitrogen fertilization management are important elements in sugarbeet production. Optimizing these factors under sprinkler irrigation can help improve sugarbeet production due to its effect on N availability and movement in the soil. A field study was conducted at Big Horn Basin Wyoming in 2014 and 2015 to determine the effect of strip tillage (ST), conventional tillage (CT) and N rates (0.0, 70.4, 140.7, 211.1 and 281.4 kg ha^-1) on sugarbeet yield, sugar content (SC) and sugar loss to molasses (SLM) grown under limited (0.75ET) and full (1ET) irrigation. Conventional tillage and strip tillage were performed early in spring of each year. Nitrogen was applied as dry urea at planting and top-dressed with liquid urea - 32% N. Triple supper phosphate (TSP) as a source of phosphorus was used. The effect of tillage systems was not statistically different in both irrigation levels in influencing SB yield, sugar content and SLM. The linear relationship between sugarbeet yield and N rates was significant, but generally 281 kg ha^-1 produced the highest response in 2014. A quadratic response of sugarbeet yield to nitrogen rates was observed under full irrigation with 140.7 kg N ha^-1 giving the highest yield (15 Mg ha^-1) in 2015. A significant interaction effect was observed between N rates and tillage systems on sugar levels under limited irrigation in the first year.  The results indicate that there is a decrease in sugar levels with increasing N rates under strip tillage. SLM was linearly effected as nitrogen rates was increased in the second year. It can be concluded that strip tillage can be used since it gives yield equivalent to conventional tillage practice.