Energy balance, costs and CO2 analysis of tillage technologies in maize cultivation

Abstract

To achieve energy independence, Lithuania and other Baltic countries are searching for new ways to produce energy. Maize is a crop that is suitable for both food and forage, as well as for the production of bioenergy. The objective of this work was to assess the energy efficiency of maize cultivation technologies in different systems of reduced tillage. The experimental research and energy assessment was carried out for five different tillage systems: DP (deep ploughing), SP (), DC (deep cultivation), SC (shallow cultivation) and NT (no tillage). The assessment of the fuel inputs for these systems revealed that the greatest amount of diesel fuel (67.2 l ha−1) was used in the traditional DP system. The reduced tillage systems required 12–58% less fuel. Lower fuel consumption reduces the costs of technological operations and reduces CO2 emissions, which are associated with the greenhouse effect. The agricultural machinery used in reduced tillage technologies emits 107–223 kg ha−1 of CO2 gas into the environment, whereas DP emits 253 kg ha−1 of CO2. The energy analysis conducted in this study showed that the greatest total energy input (approximately 18.1 GJ ha−1) was associated with the conventional deep-ploughing tillage technology. The energy inputs associated with the reduced-tillage technologies, namely SP, DC and SC, ranged from 17.1 to 17.6 GJ ha−1. The lowest energy input (16.2 GJ ha−1) was associated with the NT technology. Energy efficiency ratios for the various technologies were calculated as a function of the yield of maize grain and biomass. The best energy balance and the highest energy efficiency ratio (14.0) in maize cultivation was achieved with the NT technology. The energy efficiency ratios for DP, SP, DC and SC were 12.4, 13.4, 11.3 and 12.0, respectively.