Tuesday, 8 November 2005 - 8:30 AM
197-1

Comparison of P Forms in Animal Manure Identified by Enzymatic Hydrolysis and Solution P-31 NMR.

Zhongqi He1, Barbara Cade-Menun2, Gurpal Toor3, C. Wayne Honeycutt1, and J. Thomas Sims4. (1) USDA-ARS, New England Plant, Soil, and Water Laboratory, University of Maine, Orono, ME 04469, (2) Dept. Geological & Envl. Sci., Stanford University, Stanford, CA 94305-2115, United Kingdom, (3) Dept. of Plant & Soil Sciences, University of Delaware, Newark, DE 19717-1303, (4) University of Delaware, Department of Plant & Soil Sciences, Newark, DE 19717-1303

Both enzymatic hydrolysis and solution phosphorus-31 NMR spectroscopy have been used to characterize P forms in animal manure, however, there are no reports on comparison of the P identified by the two methods. In this study, P in 0.25 M NaOH/0.05 M EDTA extracts of wet and dried manures was comparatively investigated by the two methods. Enzymatic hydrolysis reveals that among the extracted P in a dairy manure, 56% was inorganic P, 9% simple monoester P, 6% polynucleotide-like P, 10% phytate-like P, and 18% non-hydrolyzable P. The P forms in the extracts of a poultry manure were 71% for inorganic P, 1% for monoester P, 3% for polynucleotide-like P, 15% for phytate-like P, and 9% for non-hydrolyzable P was the extracted P. The P distribution did not change dramatically in the dried samples of both manures when determined with enzyme hydrolysis, which contrasted with the results from NMR spectroscopy. In dairy manure, inorganic P was 64% of total P in wet samples but 73% in dried. Phytic acid was estimated at 6% in both wet and dried samples, and other monoesters were 14% in wet and 22% in dried samples. Phospholipids were 6% and DNA, phosphonates, pyrophosphate and polyphosphates were 1% each in both dried and wet dairy samples. The P distribution in poultry manure was 51% as inorganic P, 33% phytic acid, 12% other monoesters, and 2% each as phospholipids and DNA in dried samples; and 63% as inorganic P, 24% phytic acid, 6% other monoesters, 3% phospholipids and 1% DNA in wet samples. These observations show that the P forms detected by the two methods were not always same due to different identities and/or stability to hydrolysis. Thus the two methods are complementary to each other and provide a full spectrum of manure P characteristics.

Back to Manure, Compost and Bio-solid Use
Back to S08 Nutrient Management & Soil & Plant Analysis

Back to The ASA-CSSA-SSSA International Annual Meetings (November 6-10, 2005)