Weinberg, Z.G., Forage Preservation Research Unit, Volcani Center, Agricultural Research Organization, Bet Dagan 50250, Israel
Ashbell, G., Forage Preservation Research Unit, Volcani Center, Agricultural Research Organization, Bet Dagan 50250, Israel

Ensiling is a preservation method for moist forage crops, based on a lactic acid solid-state fermentation. Air is detrimental to silage because it enables the reactivation of detrimental aerobic microorganisms. The present review describes some of the major engineering and physical aspects of ensiling - silo types and the ensiling process - step by step. Issues considered include harvest and chopping, degree of consolidation, permeability to air ingress, sealing, additive application and unloading. Mathematical models that have been developed to simulate the ensiling process are mentioned. Experimentation methods are also described. © 2002 Elsevier Science B.V. All rights reserved.