Effect of Row Spacing and Nitrogen Rate on Root and Sucrose Yield of Sugarbeets in Southern Idaho

Research results at other locations in western U.S. indicate that a plant spacing of approximately 12 inches within rows and 20 or 22 inches between rows is necessary to obtain near maximum yields of sugarbeets (Beta vulgaris L.) and yet maintain adequate space for machinery operation (4, 6, 10). Increasing row and plant spacings with corresponding decreases in plant population have reduced root and sucrose yields (1, 9, 11). Decreasing row and plant spacings with consequent increases in plant populations may augment yields (5). The optimum row spacing and plant population for maximum sucrose production by varieties currently used by the Amalgamated Sugar Company under a high fertility level, controlled irrigations, and the climatic conditions of southern Idaho are unknown. In southern Idaho, most sugarbeets are grown in 22- or 24-inch rows with plants thinned to 9- to 12-inch spacings within the row. With these plant spacings, the factory average beet root yield from 1966 to 1969 was 20.9 tons in southwestern, 18.3 in south central and 17.8 tons in southeastern Idaho. Experimental plots and many farm fields during the same period produced 5 to 8 tons more than the average when stand, fertilizer, and irrigation water were optimized. A substantial part of the lower average yield may be due to a poor plant stand at maturity on farmers' sugarbeet fields rather than to fertility or irrigation practices. Narrower rows at optimum fertility and irrigation levels, while maintaining adequate space for modern farm machinery, may improve average yields by increasing yield compensation (when frequent skips occur) and by providing an earlier full leaf canopy. This experiment was conducted to determine the effect of plant population, as varied by row width while maintaining a uniform within-row stand, and N level on beet root and sucrose production under the climatic conditions of southern Idaho