Sugar Beet Production as Influenced by Row Orientation

In some crops, row orientation has been shown to influence yield through the effects on soil temperature. There has been no similar work on sugar beet ( Beta vulgaris L.); thus, an experiment was conducted from 1992 to 1994 to determine the effects of row orientation on the growth and production of sugar beet in Hungary. Sugar beet was grown in large field plots oriented either north‐south (N‐S) or east‐west (E‐W) on a silty clay loam soil. Leaf area development, soil and canopy temperatures, and stomatal resistance were monitored during the growing season from April to October, and root yield, sucrose concentration, and sugar yield were recorded at harvest. All three seasons were warmer and drier than normal, so large soil water deficits developed during July to October each year. Significant differences in growth were observed, with rows oriented E‐W developing 15 to 21% larger leaf area indices. The E‐W rows also had greater canopy and interrow soil temperatures and lower stomatal resistances than N‐S rows, except during the middle of the day. On days with northerly winds >2 ms −1, , air and soil surface temperatures in E‐W oriented rows were greater than in N‐S rows throughout the day. Root and sugar yields were consistently greater in N‐S rows despite having a lower sucrose concentration than beet in the E‐W oriented rows. In 1994, sugar yields were 70% less than in 1993 as a result of Cercospora beticola infestation. In all years, the reduced yield in the E‐W rows was caused by more severe water stress compared to the N‐S rows. The higher temperatures also may have led to reduced partitioning of assimilate to roots with a consequent loss of harvestable yield. The results show that, in dry years, farmers may obtain up to 9% increases in sugar yield by planting sugar beet in N‐S rows. However, these conclusions need confirmation under wetter conditions.