Zinc amendment increases the yield and industrial quality of Beta vulgaris L. cultivated in Northeast China

The sugar beet (Beta vulgaris L.) is a major industrial crop in Northeast China, but long-term or recurrent cultivation practices with low zinc (Zn) inputs have resulted in a decline in its cumulative yield and industrial quality. Hence, Zn fertilization is gaining interest in the commercial production of sugar beets; however, the efficacy and mechanism of Zn in enhancing the yield and industrial quality of sugar beets remain underexplored. A field experiment was conducted for two consecutive years (2019 and 2020) in black and albic soils of Northeast China with three levels of Zn fertilizer (0 kg ha−1, 30 kg ha−1, and 60 kg ha−1) using sugar beet cv. KWS1176. The application of Zn improved the photosynthetic performance and biomass of sugar beets and promoted the accumulation of dry matter in the roots. Zinc fertilization remarkably increased the sugar beet root yield in black and albic soils by 14.50% and 5.75%, respectively. Furthermore, the K and Na contents decreased in sugar beet roots cultivated in both soil types by augmenting Zn, whereas the sugar content increased significantly. The application of Zn considerably increased the biological sugar and white sugar yield by 15.25%, and 16.71% on average in black soil and 6.75% and 5.90% in albic soil, respectively. Correlation analysis showed that the root and white sugar yields were closely related to Zn accumulation in sugar beet roots. The amendment of cultivable lands with Zn fertilizer, preferably at a rate of 30 kg ha−1, is an effective strategy to simultaneously improve the root yield and quality of sugar beets, with better efficacy in black soils than in albic soils. Our findings provide a scientific basis for nutrient management in sugar beet planting and a step forward toward the sustainable development of the sugar industry.