Six combinations of grazing, tillage, and herbicides were studied during 2 yr in a randomized block design to determine alfalfa (Medicago sativa) survival, corn (Zea mays) plant populations and corn growth in an alfalfa-corn rotation. Alfalfa was overseeded with rye (Secale cereale) in autumn prior to planting corn in spring of each year. Treatments were 1) non-grazed control with standard chemical treatments for no-till establishment of corn, 2) grazing alfalfa, then grazing rye until corn planting followed by dicamba application, 3) alfalfa grazing plus glyphosate prior to corn planting, 4) treatment 3 plus grazing prior to rye jointing, and 5) alfalfa grazing plus autumn application of glyphosate, 6) alfalfa grazing plus autumn disking (no herbicides). Grazing until corn planting decreased (P<0.05) alfalfa stands and rye biomass, but increased (P<0.05) corn plant populations and soil bulk density compared to shorter grazing periods. Grazing prior to rye jointing increased (P <0.05) soil bulk density and corn plant populations, and decreased (P<0.05) rye biomass compared to no spring grazing. Autumn disking decreased (P<0.05) bulk density, but generally provided less (P<0.05) control of alfalfa compared to autumn application of glyphosate. Autumn disking and glyphosate application (Trts. 5 and 6) increased (P<0.05) rye biomass compared to no autumn treatment (Trts. 3 and 4). Applying glyphosate prior to corn planting (Trts. 3 and 4) improved (P<0.05) corn populations and growth compared to autumn glyphosate or disking (Trts. 5 and 6) and was similar to conventional no-till establishment (Trt. 1). Herbicides were necessary to completely kill alfalfa, but grazing reduced TNC in alfalfa roots and alfalfa plant persistence. / Master of Science
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/45050 |
| Date | 07 October 2005 |
| Creators | Morris, Jennifer L. |
| Contributors | Crop and Soil Environmental Sciences, Allen, Vivien G., Parrish, David J., Hagood, Edward S., Fontenot, Joseph P. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Thesis, Text |
| Format | xi, 81 leaves, BTD, application/pdf, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
| Relation | OCLC# 29687319, LD5655.V855_1993.M669.pdf |
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