Dissertation/Thesis Abstract

Investigating Limitations to Nitrogen Fixation by Leguminous Cover Crops in South Texas
by Kasper, Stephanie L., M.S., The University of Texas Rio Grande Valley, 2019, 90; 13812246
Abstract (Summary)

Many farms use leguminous cover crops as a nutrient management strategy to reduce their need for nitrogen fertilizer. Biological nitrogen fixation (BNF) depends on a symbiotic relationship between legumes and nitrogen-fixing rhizobia. Under certain conditions despite inoculation with appropriate rhizobial strains, this symbiosis fails to form. Such failure was observed in a 14-acre winter cover crop trial in the Rio Grande Valley of Texas when three legume species (forage pea, crimson clover, and hairy vetch) produced no signs of nodulation and nitrogen fixation. This study examined nitrogen, phosphorus, moisture, micronutrients and biotic interference as potential causes for the failure and assessed arbuscular mycorrhizal fungi as a potential intervention to improve nodulation outcomes. Results from a controlled greenhouse study confirm moisture and micronutrient deficiencies as major suspects in the nodulation failure. Nitrogen and phosphorus deficiencies however were not likely causes, nor was mycorrhizal inoculation an effective intervention to improve nodulation results.

Indexing (document details)
Advisor: Racelis, Alexis E.
Commitee: Christoffersen, Bradley O., Soti, Pushpa G.
School: The University of Texas Rio Grande Valley
Department: Biology
School Location: United States -- Texas
Source: MAI 58/06M(E), Masters Abstracts International
Subjects: Agriculture, Plant sciences, Sustainability
Keywords: Cover crops, Legumes, Nitrogen fixation
Publication Number: 13812246
ISBN: 978-1-392-28061-4
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