IMPROVEMENT OF DAIRY FORAGE AND MANURE MANAGEMENT TO REDUCE ENVIRONMENTAL RISK
Location: Environmentally Integrated Dairy Management Research Unit
Title: Manure application methods to minimize ammonia losses and maximize crop N use
Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: February 4, 2011
Publication Date: February 15, 2011
Citation: Jokela, W.E., Meisinger, J.J. 2011. Manure application methods to minimize ammonia losses and maximize crop N use. Meeting Proceedings. Feb. 15-16, 2011..
Ammonia volatilization is a major N loss process for surface-applied manures and urea fertilizers. The lost ammonia is important for both agricultural and non-agricultural ecosystems because it: a) is a direct loss of plant available N to the farmer, b) reduces the N:P ratio in manure, which accelerates P build-up in soils, c) contributes to eutrophication in aquatic ecosystems, especially marine, through atmospheric transport and deposition, and d) can contribute to air quality degradation by forming fine particulates. Agriculture is the major source of ammonia emissions to the atmosphere, with most coming from livestock production. Most efforts to reduce agricultural ammonia losses have focused on land application, the single largest source. The loss of ammonia after manure application is affected by several factors: manure characteristics (ammonium and dry matter content), application method and time of incorporation, weather (wind, temperature, rain), soil properties, and surface residues and vegetation. The most effective management practices to reduce ammonia losses are those that incorporate manure into the soil. Most ammonia is lost soon after application, typically in the first 4 to 12 hours, emphasizing the need for prompt incorporation. The most common practice to minimize ammonia loss is to follow manure application with a tillage operation such as chisel plowing or disking, which can reduce ammonia losses by 90% or more if done immediately. One-pass alternatives that are equally effective include injection or other methods of direct incorporation with disk or s-tine attachments. In perennial forage crops, newer options include drop hose, trailing shoe, or aerator-incorporator methods, which can reduce ammonia-N loss by 20 to 60% compared to surface broadcast. Use of these improved manure application methods can have both environmental and economic benefits by reducing the need for costly fertilizer N, while minimizing release of ammonia to the environment.