Effect of poultry litter application method and rainfall and delayed wrapping on warm-season grass baleage

Authors: Nieman, Christine; Coblentz, Wayne; Moore, Philip; Akins, Matthew

Submitted to: Agronomy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/15/2023
Publication Date: 7/18/2023
Citation: Nieman, C.C., Coblentz, W.K., Moore Jr, P.A., Akins, M.S. 2023. Effect of poultry litter application method and rainfall and delayed wrapping on warm-season grass baleage. Agronomy. 13;1896. https://doi.org/10.3390/agronomy13071896.
DOI: https://doi.org/10.3390/agronomy13071896

Interpretive Summary: Forages in the southeast are commonly fertilized with poultry litter to increase forage production and nutritive vale. Generally, litter is broadcast over the soil and forage surface, which can lead to nutrient losses from rainfall and nitrogen (N) loss through ammonia volatilization. Injecting poultry litter below the soil surface reduces volatilization and run off and increases forage yield and forage N concentrations compared to surface applied poultry litter. Harvest and storage of forage as baleage is another technology that can increase forage production efficiency. Frequent rain events and humidity in the southeast can prevent timely harvest of forages and cause extended dry down times which can result in nutrient and dry matter losses. Baleage allows for greater flexibility in harvest because forage can be baled at 40-70% moisture. Despite this flexibility, unplanned rain events that may cause delayed wrapping of baled forages may still occur. This study evaluated the effects of subsurface versus surface applied poultry litter and rain plus delayed wrapping versus bales without rain that were wrapped within two hours on nutritive value and fermentation parameters of warm-season baleage. Subsurface amendment of poultry litter had several positive effects on final bale nutritive composition including increased crude protein, lactic acid, acetic acid, and total acids compared to bales with surface applied litter. Increased butyric acid, ethanol, and total alcohol in bales with surface applied poultry litter indicate lower overall nutritive value and possibly increased activity of clostridial bacteria or other undesirable bacteria due to contamination from surface applied poultry litter. Rain and delayed wrapping of 17 h caused reduced starch and slightly increased fiber components, but lactic acid and total acid concentration did not differ in the final bale nutritive composition. Overall, amendment of subsurface applied poultry litter improved final bale nutritive composition, while rain plus delayed wrapping had negligible effects on final bale nutritive composition of warm-season grass baleage.

Technical Abstract: Poultry litter is a widely available fertilizer in the southeast USA and subsurface application of litter can increase both forage production and nutritive value. Frequent rainfall events and high humidity often limit time available for hay curing; baled silage techniques can increase harvest time flexibility. Unfortunately, rainfall events can still occur without forecast during harvest events, resulting in delayed baling or wrapping. The objective of this study was to evaluate poultry litter amendment methods, subsurface (SUB) and surface (SURF), and the effect of no-rain (NR) versus rain and 17-h delayed wrapping (RDW) on warm-season grass baleage. Data were analyzed as a randomized complete block design with two amendment treatments and two post-baling treatments. Crude protein (CP) was greater (p < 0.01) and neutral detergent fiber (NDF) was lesser (p < 0.01) in both pre- and post—ensiled bales with subsurface applied poultry litter. Rain and delayed wrapping resulted in lower pH (p = 0.03), starch (p <0.01), and water-soluble carbohydrates (p < 0.01) in pre-ensiled, compared to bales that did not receive rain and were wrapped within 2 h, while post-ensiled bales only differed in lower (p < 0.01) starch and slightly greater (p < 0.01) NDF in RDW. Lactic acid (p < 0.01), acetic acid (p < 0.01), and total acids (p = 0.03) were greater in SUB, while butyric acid tended to be greater (p = 0.09), and alcohols (p = 0.05) were greater in SURF. Bales from RDW and NR only differed by greater (p < 0.01) propionic acid concentrations in NR. Under the conditions of this experiment, subsurface application of poultry litter increased final nutritive value, while rain and delayed wrapping of 17 h had few effects on the final nutritive value of warm-season grass baleage.