Analysis of structural factors affecting the energy performance of forage harvesters: review and optimization guidelines

This structured critical review examines how structural, operational, and crop-related factors affect the energy performance of self-propelled forage harvesters. A documented literature search included journal articles, conference papers, technical reports, and DLG test reports. Power demand, specific energy, specific fuel consumption, throughput, and forage quality were compared. Particular attention is given to the theoretical length of cut (LOC) as a kinematic indicator linking feed velocity, cutterhead speed, and the number of active knives. The reviewed evidence shows that energy performance results from the combined effects of LOC, material throughput, crop properties, knife condition, roller-shredding intensity, header configuration, and engine-load control. Field-test data indicate that the reduction in specific fuel consumption with increasing LOC may reach a plateau rather than continue linearly. A conceptual framework is proposed to organize the interactions and trade-offs among energy demand, productivity, and forage quality. The framework provides a basis for selecting variables in future experimental and predictive studies of forage-harvester performance.