Author ORCID Identifier

https://orcid.org/0000-0001-7775-1564

Year of Publication

2021

Degree Name

Doctor of Philosophy (PhD)

Document Type

Doctoral Dissertation

College

Agriculture, Food and Environment

Department/School/Program

Plant and Soil Sciences

First Advisor

Dr. David H. McNear, Jr.

Abstract

Plant roots are often overlooked when making nutrient management decisions. Evaluating differences in P acquisition strategies and cycling resulting from years of shoot-specific plant breeding will aid in reducing fertilizer inputs, with the ultimate goal of improving economic sustainability of crop production and preservation of ecosystem services. To achieve this goal, this research screened a diverse panel of winter wheat cultivars that included old and modern, dwarfed and wild type varieties for physical and chemical root phenotypes related to P acquisition. Old cultivars had larger root systems with more roots that grew two times faster than intermediate/modern cultivars. Wild type roots contained approximately two times more oxalic acid than semi-dwarfs. To evaluate how these differences impacted P uptake, cultivars were categorized into four groups defining their P extraction potential (PEP) based on organic acid content and root system size and grown in soils with deficient and adequate P. PEP was found to correlate with both P use efficiency and root P acquisition efficiency. A mesocosm study conducted over three years revealed differences in the rate of root decomposition under differing crop rotations and native soil fertility. Overall, this research has identified winter wheat cultivars that could be useful for producers as a cover crop that would acquire P efficiently and release this P for the following crop during decomposition.

Digital Object Identifier (DOI)

https://doi.org/10.13023/etd.2021.319

Funding Information

The entirety of this research was supported by the United States Department of Agriculture National Institute of Food and Agriculture Grant (no.: 2016-67019-25281) in 2017-2021.

Available for download on Wednesday, August 10, 2022

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