The Effects of Soil Application of Digestate Enriched with P, K, Mg and B on Yield and Processing Value of Sugar Beets

Abstract

The aim of this research was to find out if the supplementation of digestate, a by-product of the anaerobic digestion of sugar beet pulp, with phosphorus, potassium, magnesium and boron can improve digestate performance as a soil amendment. The materials of this study were: digestate and sugar beet roots (Beta vulgaris cv. Fighter). A field trial was carried out on sugar beet growth under soil application conditions of solid and liquid digestate fractions with or without supplementation with P, K, Mg and B. It was shown that the root yield obtained from the plots amended with digestate supplemented with P, K, Mg and B was higher compared to the yield of other treatments. Soil amendment with digestate supplemented with P, K, Mg and B affected quality parameters of sugar beet roots. An increase in the following parameters under the effects of enriched digestate application was found: sucrose content, dry residue, pomace content, inverted sugars, α-amino and amide nitrogen fractions, as well as sodium and potassium content. A reduction in the content of conductometric ash was noted but this difference was not proven. The enrichment of digestate with P, K, Mg and B resulted in the beneficial modification of beet roots’ processing parameters with the exception of the predicted content of sugar in molasses. In the case of the liquid fraction and its supplementation with P, K, Mg and B, six among eleven technological quality parameters were increased.