Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 2/8/2018
Publication Date: 8/19/2020
Citation: Coblentz, W.K. 2020. Post-harvest physiology. Book Chapter. Pages 721-748.
Technical Abstract: Weather and management constraints, as well as the intended use of the harvested forage, all influence the forage harvest system selected by the producer. Generally, maximum retention of dry matter from harvested forage crops is achieved at moistures intermediate between the standing fresh crop and dry hay. This practice avoids the potentially large storage losses that can occur with high-moisture silages, as well as the large field losses associated with very dry hay. Numerous plant microbial and physiological processes occur during forage harvest and storage, and many are deleterious. One notable exception is the anaerobic fermentation of forages into silages dominated by production of lactic acid. These physiological processes are influenced by pre-harvest factors, as well as harvest and storage variables. Avoidance of rain damage and facilitation of rapid drying to minimize other losses are key considerations in hay production to avoid excessive plant enzymatic and microbial activity. Using silage to preserve forage greatly reduces negative effects of rain during field and storage phases compared with dry hay. Rapid elimination of oxygen and proper maintenance of anaerobic conditions in silage minimizes aerobic respiration by plant enzymes and microbes. Management strategies for conserving forage crops should be based on a thorough understanding of post-harvest physiological processes.