Sugar beet fertilisation for sustainable yield under climate change conditions

The aim of this study was to determine how different fertiliser systems affect sugar beet (Beta vulgaris L.) productivity, water-use efficiency (WUE) index, nutrient uptake and balance and establish the efficient fertilisation of the plant. A randomized experimental design with four replications as factorial arrangement with four treatments: (1) without fertilisers (control), (2) mineral fertilisation (MF), (3) alternative organic-mineral fertilisation (OMF) and (4) organic-mineral fertilisation supplemented with boron (B) (OMF+B), was used. The results showed that sugar beet root yield, gross and white sugar yield were significantly affected (P < 0.05) by all fertilisation treatments. The highest average of the aforementioned parameters was obtained in OMF+B treatment: 63.5, 10.73 and 8.86 t ha-1, respectively, that included combined application of the mineral fertilisers and winter wheat straw plus B twice foliar applied. OMF+B had a more pronounced effect on sugar beet productivity in the year of hot and moderately humid growing season (2018) than in dry (2017) and moderate (2019) years. OMF+B resulted in a positive nutrient balance in the soil and the highest WUE index (44.7 kg ha-1 mm-1), provided efficient use of water and the sustainability of sugar beet cultivation under climate change conditions, while mineral fertilisation led to nutrient imbalance and low stability. The accumulation of sugar in the roots mainly depended on the dry weather in September. The driest September of 2019 contributed to the highest sugar content in the roots – 18.2–18.5%, while moderately and too humid weather in September 2017 and 2018 caused a significant decrease (P < 0.05) in sugar content to 17.0–17.5% and 14.9–15.2%, respectively.