Degree Type

Dissertation

Date of Award

2017

Degree Name

Doctor of Philosophy

Department

Agronomy

Major

Crop Production and Physiology

First Advisor

Andrew W. Lenssen

Second Advisor

Kenneth J. Moore

Abstract

Natural resources degradation in conventional cropping systems and renewable fuels agendas underscore the importance of developing alternative cropping systems which can both (1) conserve natural resources and (2) meet global demands for food, feed, fiber, and fuel. The integration of perennial groundcover (PGC) into annual grain cropping systems is uniquely positioned to achieve production goals and alleviate the degradation of natural resources. We established kentucky bluegrass (KB) (Poa pratensis L.) or creeping red fescue (CF) (Festuca rubra L.) as PGC concurrently with either three unique maize hybrids or soybean, and field studies were conducted with the objective of (i) establishing PGC under either maize or soybean, and (ii) assessing the impact of establishing PGC on developmental morphology and yield of the annual grain crop. Subsequent field studies were conducted in the early post-establishment production years with the objectives of (i) assessing the impact of established PGC on developmental morphology and yield of the maize crop, (ii) evaluating persistence of established PGC, and (iii) assessing the impact of established PGC on the weed community. We then developed an Agricultural Production Systems sIMulator (APSIM) simulation to address key components for the management of this cropping system, namely the necessary perennial groundcover dormancy period and level of suppression so as to support the grain and biomass yield of the annual maize crop. During the establishment year, maize and soybean yield in the no PGC control were 27-84% greater than the PGC treatments. However, maize grain yield and ethanol yield were similar at one location. In the post-establishment years, maize grain yield for the no PGC treatments was 23-73% greater than the PGC treatments. Ethanol yield was 12-119% greater, protein concentration was 9% greater, and starch concentration was 1% lower in the no PGC treatment maize than in PGC treatment maize. Maize hybrid by cover interaction was significant, with inconsistent maize hybrid responses to the PGC system. These results indicate that further research is needed to identify compatible grass and grain crop varieties, and effective management techniques to achieve natural resources benefits in row crop production while supporting the annual grain crop yield.

Copyright Owner

Cynthia Anna Bartel

Language

en

File Format

application/pdf

File Size

142 pages

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