Sweet sorghum - Biomass production and energy balance at different levels of agricultural inputs. A six-year field experiment in north-eastern Poland

Abstract

Abstract Sweet sorghum (Sorghum bicolor (L.) Moench) is an energy crop with low soil requirements (high tolerance to low-quality soils) that can potentially compete with the maize (Zea mays L.) monocultures. This paper presents the results of a 6-year field experiment investigating the biomass yield and energy efficiency of sweet sorghum grown under high-input and low-input production technologies. The experiment was conducted in north-eastern Poland. Dry matter yield was higher in the high-input production technology (15.4 Mg ha−1). Biomass yield in the low-input production technology was 16 % lower on average. The demand for energy in the production of sweet sorghum biomass was determined by the energy inputs associated with farming operations in the compared production technologies. The low-input technology was characterized by lower energy consumption (14.9-15.8 GJ ha−1). Energy inputs increased by 46 % in the high-input technology of sweet sorghum production. The energy gain of sweet sorghum biomass ranged from 170 (low-input technology) to 226 GJ ha−1 (high-input technology). In north-eastern Poland, the energy efficiency of sweet sorghum biomass was higher in the low-input technology.