Application of sugar beet pulp digestate as a soil amendment in the production of energy maize

Abstract

This study aimed to determine the suitability of sugar beet pulp digestion by-products as soil amendments for maize grown for energy purposes. In a plot experiment, nitrogen fertilizer at a standard rate of 200 kg N ha−1 was applied as a control vs. treatment with solid and liquid digestate fractions. Digestate was obtained from a gasifier processing only sugar beet pulp. Following harvest, heating and calorific values were determined together with the yield and chemical composition of the maize cob and stover. It was found that soil amendment with crude (unseparated) digestate or its two fractions (separated into liquid and solid) produced higher yields of maize cobs and stover compared with the application of standard fertilizer. An analysis of the energy value of the maize plant revealed differences between the studied soil treatments. Cobs obtained from plots treated with the digestate showed higher calorific and heating values than those obtained from control plots; however, maize stover from control plots showed higher calorific and heating values compared with plants from other experimental plots. It can be concluded that by-products obtained from sugar beet pulp digestion can be alternatively used as a soil amendment for maize production in a crop rotation with sugar beet. Among studied amendments the solid fraction of the digestate was found to have the best performance.