Mineralizable phosphorus, nitrogen, and carbon relationships in dairy manure at various carbon-to-phosphorus ratios.
Phosphorus (P) in animal manure can be an important nutrient for crops or an environmental contaminant if in excess. Organic P in dairy manure may add to the environmentally bioactive P pools upon mineralization. A 353d incubation study of manures containing C:P between 83 and 130:1 was conducted to determine linkages between C and P transformations and the effects of C:P on the immobilization-mineralization of manure P. As C:P widened from 83:1 to 130:1, P mineralization increased and phosphate accumulated at rates between 0.013 and 0.021mgkg(-1) d(-1). Water-extractable C was positively correlated with N:P, particularly at narrow C:P (P<0.001). Absence of a negative feedback by phosphate suggested that P mineralization occurred with degradation of organic P-containing C substrates and appeared incidental to microbial P needs. Carbon content in manure may be managed to lower risks of elevated soluble P and C losses under non-limiting N conditions.
Dao
Thanh H
TH
USDA-ARS, Environmental Management and ByProducts Utilization Laboratory, BARC-East, Bldg. 306 Powder Mill Road, Beltsville, MD 20705, USA. thanh.dao@ars.usda.gov
Schwartz
Robert C
RC
D000818:Animals; D002244:Carbon / Q000032:analysis*; D002417:Cattle; D003612:Dairying; D007700:Kinetics; D008372:Manure / Q000032:analysis*; D008903:Minerals / Q000737:chemistry*; D009584:Nitrogen / Q000032:analysis*; D010758:Phosphorus / Q000032:analysis*
D008372:Manure; D008903:Minerals; D010758:Phosphorus; D002244:Carbon; D009584:Nitrogen