Rain damage on wilting forages

Authors: Coblentz, Wayne

Submitted to: Popular Publication
Publication Type: Popular Publication
Publication Acceptance Date: 5/1/2019
Publication Date: 5/11/2019
Citation: Coblentz, W.K. 2019. Rain damage on wilting forages. Popular Publication. pp. 16-17,19.

Interpretive Summary:

Technical Abstract: A common problem encountered by hay or silage producers is how to manage production schedules around unfavorable weather, and what damage is done to wilting forage crops as a result of unpredictable rainfall events. Estimating damage to wilting forage crops subjected to rainfall is more complex than simply quantifying nutrient leaching, or the consequences of extended or reactivated plant respiration. Other (secondary) consequences of uncooperative weather also may include: i) increased leaf and/or DM losses from any additional swath manipulation required to dry rain-damaged forages; ii) spontaneous heating and/or combustion that occurs when producers try to complete baling operations of incompletely wilted hays prior to an oncoming rainfall event; iii) poor silage fermentation; and iv) excessively mature forage that results from delaying haying or silage-harvesting operations until weather is more favorable. Generally, research results suggest that damage to wilting forages becomes more severe as the forage dries, and often increases with rainfall amount. Prolonged exposure in the field, coupled with poor drying conditions and/or multiple rainfall events, is highly problematic, causing substantial increases in the pre-ensiled forage pH and significant losses of sugars. When ensiling rain-damaged alfalfa, producers should consider wilting forages to < 60% moisture, and using a silage inoculant formulated to support production of lactic acid. These efforts will decrease the risk of secondary (clostridial) fermentations dominated by production of ammonia and butyric acid as fermentation products.