Effects of Weed-Control Treatments and Plant Density on Root Yield and Sugar Content of Sugar Beet

This study was conducted to investigate the effects of weed-control treatments and plant densities on root yield and sugar content of sugar beet in the 2015, 2016, and 2017 growing seasons in Eskisehir, Turkiye. Weed-control treatments were designed considering the applications of sugar beet farmers and non-weed management (T-0), pre-emergence herbicide (T-1), post-emergence herbicide (T-2), T-1 + T-2 (T-3), T-1 + hand-hoeing (T-4), and weed-free (T-5) with continuous hand-hoeing. Five plant densities were arranged in different row spacings of 30 (D-1), 35 (D-2), 40 (D-3), 45 (D-4), and 50 (D-5) cm. Root yield, sugar content, yield reduction, weed-control efficiency, weed density, weed frequency, weed fresh weight, and weed dry weight were investigated. The results showed that the highest root yield and sugar content were obtained from T-5 with 117.1 ton ha(-1) and 15.17%, respectively. The lowest weed density and weed fresh and dry weights were measured in T-4 and T-3. Depending on the year, the root yield decreased by 100% when there was no weed management. Among the plant densities, D-1 gave the highest sugar content with 13.22%, while the highest root yield (63.9 ton ha(-1)) was observed in D-3. The most common weed, Amaranthus retroflexus L., had an 85% frequency. The most intense weed was Chenopodium album L., with 38.86 plant m(-2). Weed-control treatments significantly enhanced sugar beet root yield and sugar content; furthermore, T-4 produced yields similar to weed-free treatment (T-5). To suppress weeds in sugar beet production, higher plant densities (30, 35, and 40 cm) are suggested if mechanization facilities are available.