Title page for ETD etd-01052005-084936


Type of Document Master's Thesis
Author Teany, Laura Ellen
Author's Email Address lauteany@vt.edu
URN etd-01052005-084936
Title Phosphorus Losses from Simulated Dairy Mangement Intensive Grazing Forage System
Degree Master of Science
Department Biological Systems Engineering
Advisory Committee
Advisor Name Title
Gay, Susan W. Committee Chair
Benham, Brian L. Committee Member
Knowlton, Katharine F. Committee Member
Smith, S. Raymond Committee Member
Keywords
  • phosphorus
  • pasture management
  • nonpoint source pollution
  • managemen intensive grazing
  • dairy grazing
  • pasture forages
Date of Defense 2004-09-22
Availability unrestricted
Abstract
Dairy producers across the country are evaluating the effectiveness of management intensive grazing (MIG) systems as a means of reducing the economic pressures of confinement feeding and manure handling. Systems using MIG have been promoted as an environmentally safer way of managing nutrient balance on Center. However, little research has been conducted to evaluate how these systems affect phosphorus (P) loss from the Center through runoff and forage removal. The goal of this study was to investigate the effects of forage type and manure density on P levels in runoff from release plots that simulated a MIG dairy system.

Two forage treatments were planted on runoff release plots and applied with three manure density treatments and four replications of each combination for a total of 24 plots. Orchardgrass (Dactylis glomerata) and a broad-leafed forage treatment consisting of buckhorn plantain (Plantago lanceolata), red clover (Trifolium pratense), and alfalfa (Medicago sativa) were planted on the runoff release plots in early spring. Manure densities with no manure (control), a density simulating a low stocking density (low), and a density simulating high stocking density (high) were applied to plots during grazing simulations. Six rainfall simulations were conducted over the season simulating grazing conditions when forage was removed and re-growth conditions when forage had reached its target re-growth height before re-grazing occurred. Thirty minutes of runoff was collected from the runoff release plots to determine first flush phosphorus losses from the various treatments.

Mass losses of total phosphorus (TP) for manure treatments in series 1 were significant due to plot installation disturbance. No significant effect for ortho-phosphorus (ortho-P), particulate phosphorus (PP) or TP concentration or mass losses were observed for other simulation series. Significantly higher mass losses were observed in series 1 for both forage treatments, again due to installation disturbance. Seasonal mass losses for TP were significantly lower for the orchardgrass treatment.

Forage mass removal over the season increased as the stands established. Orchardgrass treatments appeared to control P losses earlier in the season, while broadleaf treatments observed a steady increase in ortho-P losses up to series 5. Both mass and concentration losses of TP were controlled earlier in the season by orchardgrass, while PP showed no significant mass or concentration loss effects.

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  Abstract.pdf 132.85 Kb 00:00:36 00:00:18 00:00:16 00:00:08 < 00:00:01
  AppendixA.pdf 66.76 Kb 00:00:18 00:00:09 00:00:08 00:00:04 < 00:00:01
  AppendixB.pdf 137.50 Kb 00:00:38 00:00:19 00:00:17 00:00:08 < 00:00:01
  AppendixC.pdf 53.04 Kb 00:00:14 00:00:07 00:00:06 00:00:03 < 00:00:01
  AppendixD.pdf 106.15 Kb 00:00:29 00:00:15 00:00:13 00:00:06 < 00:00:01
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  AppendixG.pdf 120.78 Kb 00:00:33 00:00:17 00:00:15 00:00:07 < 00:00:01
  AppendixH.pdf 65.75 Kb 00:00:18 00:00:09 00:00:08 00:00:04 < 00:00:01
  AppendixI.pdf 48.71 Kb 00:00:13 00:00:06 00:00:06 00:00:03 < 00:00:01
  AppendixJ.pdf 126.58 Kb 00:00:35 00:00:18 00:00:15 00:00:07 < 00:00:01
  AppendixK.pdf 36.64 Kb 00:00:10 00:00:05 00:00:04 00:00:02 < 00:00:01
  Chapter1.pdf 63.14 Kb 00:00:17 00:00:09 00:00:07 00:00:03 < 00:00:01
  Chapter2.pdf 139.95 Kb 00:00:38 00:00:19 00:00:17 00:00:08 < 00:00:01
  Chapter3.pdf 206.24 Kb 00:00:57 00:00:29 00:00:25 00:00:12 00:00:01
  Chapter4.pdf 246.78 Kb 00:01:08 00:00:35 00:00:30 00:00:15 00:00:01
  Chapter5.pdf 76.12 Kb 00:00:21 00:00:10 00:00:09 00:00:04 < 00:00:01
  References.pdf 113.43 Kb 00:00:31 00:00:16 00:00:14 00:00:07 < 00:00:01
  Title.pdf 53.67 Kb 00:00:14 00:00:07 00:00:06 00:00:03 < 00:00:01
  vitae.pdf 27.66 Kb 00:00:07 00:00:03 00:00:03 00:00:01 < 00:00:01

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