United States Department of Agriculture: Agricultural Research Service, Lincoln, Nebraska
United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications
Accessibility Remediation
If you are unable to use this item in its current form due to accessibility barriers, you may request remediation through our remediation request form.
Document Type
Article
Date of this Version
2006
Abstract
Surface-applied manures create a potential phosphorus (P) runoff hazard, especially when unincorporated. In such cases, the concentration of water- extractable P in the manure has been correlated to soluble P concentrations in runoff. This study evaluated the influence of holding time, sample-handling procedure, and filtration method on measurement of the water-extractable P content of manures in a 3 ×3 ×2 factorial arrangement of treatments. A two-way interaction between holding time and sample-handling procedure occurred for most samples. Six samples had waterextractable P concentrations that were less than or equal to dried and dried/ground treatments. Only one sample had higher water-extractable P concentrations for fresh than for dried and dried/ground treatments. When significant differences occurred as a result of the filtration method, results for Whatman No. 40 filters, with a larger pore size than 0.45 μm nitrocellulose membranes, were usually higher. There was no significant difference in the coefficient of variation across sample-handling procedures, suggesting that efforts to dry and/or grind samples were not needed. These results support the adoption of a standardized protocol for measuring water-extractable P in manures that represents the appropriate balance between the ease of implementation and the strength of the correlation to P runoff concentrations.
Comments
Published in Communications in Soil Science and Plant Analysis, 37: 451–463, 2006. DOI: 10.1080/00103620500449328