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ARS Home » Midwest Area » Madison, Wisconsin » U.S. Dairy Forage Research Center » Research » Publications at this Location » Publication #142931
Title: EFFECTS OF MANURE HANDLING SYSTEMS ON VOLATILE NITROGEN LOSS FROM DAIRY MANURE

Author
item MOREIRA, V - UW-MADISON
item Satter, Larry

Submitted to: Journal of Dairy Science
Publication Type: Abstract Only
Publication Acceptance Date: 7/25/2002
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: The objective was to evaluate the effect of manure handling systems on nitrogen (N) loss from dairy manure. The nitrogen to phosphorus ratio (N:P) in manure was used as the basis of system comparison. N:P in dairy manure at time of excretion is likely to range from 6 to 7. As N is volatilized from manure, the N:P ratio in manure is reduced, since P does not volatilize. This assumes neither N nor P is lost due to runoff or leaching during collection and storage of manure. Results from 778 manure samples submitted by farmers to four laboratories located in MN, OH, PA, and WI were summarized. Individual analyses within laboratory source was used as error term, and samples deviating more than 2.5 x SDM were deleted from each laboratory data set. Manure storage systems from PA and WI were identified as earthen basin (EB), daily haul (DH), bedded pack (BP) and stack (S). EB (N:P=5.37, n=183) had higher (P<.004) N:P than BP (4.53, n=30), but did not differ from DH (5.12, n=77, P>.25) or S (4.64, n=9, P>.14). No differences were found between bedding type (inorganic vs. organic, n=53 and 71, P>.36) in WI samples, or covered and uncovered storage (n=10 and 35, P>.99) in PA samples. Method of loading manure into slurry storage (bottom loading vs. top loading) from PA samples affected N loss, with bottom and top loading having N:P of 5.35 and 4.73 (n=27 and 51, P<.02). Manure samples submitted for analyses during the summer (4.90, n=107) or fall (4.67, n=240) had a lower N:P ratio, suggesting greater volatile N loss during the warm part of the year (spring, 5.05, n=267; winter, 5.61, n=132). If we assume an average N:P of 6.5 in dairy manure at time of excretion then N losses from time of excretion until removal of manure from storage ranged from 2-36%. Based on manure sampled from 7 dairy farms in WI, and information about the diets fed on these farms, excreted N:P was estimated to be 6.78. Manure sampled from these farms in the spring of 2001 when storage facilities were being emptied indicated that N losses ranged from 4% (twice daily free stall scraping with DH) to 23.5% (twice daily free stall scraping and top-loading of a 2-3wk storage pit).