HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (14) Citing Articles via Google Scholar Google Scholar Articles by Toor, G. S. Articles by Sims, J. T. Search for Related Content PubMed PubMed Citation Articles by Toor, G. S. Articles by Sims, J. T. Agricola Articles by Toor, G. S. Articles by Sims, J. T. Related Collections Surface Water Quality Best Management Practices Nutrient Management Water Pollution Animal Waste

Establishing a Linkage between Phosphorus Forms in Dairy Diets, Feces, and Manures

^a Department of Plant and Soil Sciences, University of Delaware, Newark, DE 19716
^b Geological and Environmental Sciences, Stanford University, Stanford, CA 94305-2115

View larger version (14K): [in a new window]   Fig. 1. Relationship between total P concentrations in diets and feces of lactating cows. Open circles represents data from Dou et al. (2003) while black data points are from the present study.

View larger version (28K): [in a new window]   Fig. 2. Example 31P nuclear magnetic resonance (NMR) spectra of diets, feces, and manures from (a) low-P-diet farm and (b) high-P-diet farm. The main spectra are plotted to show orthophosphate at the same height, to give relative peak heights. Inset peaks show expanded regions of the main spectra.

View larger version (19K): [in a new window]   Fig. 3. Details showing the peaks for phytic acid in diet, feces, and manure samples, using samples collected from Farm C as an example. A spectrum for pure phytic acid, also extracted with NaOH-EDTA in the same manner as the farm samples, is shown on the bottom, with the P1, P2, P3, P4, and P6 peaks labeled. The areas under the same four peaks in the farm samples were determined both by manual plotting after integration and by spectral deconvolution. For the diet, feces, and manure samples, the solid line indicates the original spectrum, while the dotted lines show the phytic acid peaks as determined by spectral deconvolution. Other peaks determined by spectral deconvolution are not shown. Spectra are plotted with 1-Hz line-broadening.

View larger version (29K): [in a new window]   Fig. 4. Relationship between diet, feces, and manure total P with orthophosphate and phytic acid.