Energy Use of Different Farming Systems in Long-Term Trial

Abstract

This study evaluate the effects of different types of agricultural systems and their managements on energy balance over 45-year period (1970–2015). Agricultural systems were (i) spring barley and (ii) winter wheat monocultures with different types of organic supply (straw incorporation, straw incorporation + green manuring, green manuring and control without organic supply) and (iii) Norfolk four-course system. Averaged across each half of study period, total energy inputs ranged between 10.2 GJ ha-1 year-1 for barley in Norfolk to 22.9 GJ ha-1 year-1 for wheat in monoculture with green manuring. The results indicate increase of indirect inputs in case of wheat and barley in Norfolk. The only system where the indirect input energy became lower was barley monoculture. Total energy outputs ranged between 198 GJ ha-1 year-1 for wheat in Norfolk to 88 GJ ha-1 year-1 for barley in monoculture. Norfolk system had higher output/input ratio than monocultures during whole study period. In almost all systems the effectiveness of energy use decreased during study period when comparing two halves. Yields of cereals throughout all systems were negatively dependent on energy input.