Manure nitrogen crediting and management in the USA: Survey of university faculty

Livestock production, and particularly manure management, has received envi ronmental scrutiny for years due to potential nitrate contamination in grou nd and surface waters. During the 1990s, many land grant institutions devel oped and conducted research and extension programs related to the managemen t and crediting of manure N, To assess the current status of manure N credi ting and management in the USA, a national survey of university faculty con sidered to have expertise in manure issues was conducted. A four-page mail survey was sent to one person in each state to provide qualitative and quan titative information regarding manure N management, A response rate of 86% was achieved. Groundwater and surface water quality are perceived as the to p environmental ramifications of manure N management regardless of animal s pecies. Manure N crediting for cropland is highest for poultry operations a nd lowest for beef operations. Approximately 45% of poultry manure is prope rly credited, compared with only 18% of beef manure. In addition, manure N crediting is overwhelmingly viewed as improved compared with 5 yr ago. Manu re N crediting components being emphasized include manure testing, soil N t esting, and spreader calibration. Management strategies being implemented i nclude writing manure management plans, reduced application rates, and manu re injection/incorporation. Regulation-either existing, proposed, or future -is perceived as the primary reason (61%) for producers to better manage th eir manure, More states will regulate their livestock enterprises via a per mitting process in the future, and the trend in developing nutrient plans i s toward using a combination N and P standard, rather than solely an N stan dard. Although N issues have been a focus of manure management in the past, P issues have escalated in the 1990s in terms of environmental importance.