The effect of harvest strategy on the energy potential of Jerusalem artichoke

Abstract

Jerusalem artichoke (Helianthus tuberosus L.) is a crop with a high potential for energy generation on account of its broad range of industrial applications, high yield potential and relatively low climatic and agronomic requirements. The aim of this study was to determine the effect of different harvest strategies on the energy potential of Jerusalem artichoke (JA) aerial biomass. The yield and energy efficiency (EE) ratio of JA biomass harvested (i) once (August) and (ii) twice (June and October) during the growing season were investigated in a three-year field experiment. The study was conducted in north-eastern Poland. The energy inputs (EI) in JA production were determined at 23.0–23.5 GJ ha−1 in the year of plantation establishment and at 12.1–14.6 GJ ha−1 y−1 in the second and third year. Energy inputs were 11–12% higher when JA biomass was harvested twice during the growing season. Dry matter yield (DMY) was highest in the second year (28.1 Mg ha-1), and it was 32% and 58% lower in the first and third year of the study, respectively. Dry matter yield was considerably higher when JA biomass was harvested once in August. The energy gain (EG) in JA production ranged from 144 (year 3) to 346 GJ ha−1 y−1 (year 2). The EE ratio of JA biomass production ranged from 11.3 and 12.3 (years 1 and 3) to 26.1 (year 2). Energy gain and the EE ratio were significantly higher (by 67% and 63% on average, respectively) in treatments with a single- than a double-cut harvest strategy. The study demonstrated that both productivity and the volume of energy accumulated in JA biomass can be optimized by selecting an appropriate harvest strategy (single-cut or double-cut harvest during the growing season).