Elucidating the ecophysiological complexities of maize and soybean intercrop systems to improve ecosystem services

Pelech, Elena Andrea

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https://hdl.handle.net/2142/113169 Copy

Description

Title

Elucidating the ecophysiological complexities of maize and soybean intercrop systems to improve ecosystem services

Author(s)

Pelech, Elena Andrea

Issue Date

2021-07-12

Director of Research (if dissertation) or Advisor (if thesis)

Bernacchi, Carl J

Doctoral Committee Chair(s)

Ainsworth, Elizabeth A

Committee Member(s)

• Ort, Don R
• Davis, Adam

Department of Study

Plant Biology

Discipline

Plant Biology

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• Plant biology
• Intercropping
• Maize
• Soybean
• Resource use
• Plant physiology

Abstract

Intercropping, cultivating more than one species in the same field, has been practised for millennia by smallholder farmers and indigenous peoples, and is still prevalent across the globe. Recent studies have found evidence of increased production per unit area, efficient resource-use, and enhanced yield stability in plant mixtures relative to monocultures, particularly by cereal-legume intercrops. The mechanisms behind such advantages have been attributed to the relaxation of competition due to niche complementarity, facilitation, and/or selection. Realising these ecological principles in agricultural systems may reconcile with other approaches to sustainably intensify crop production and meet the food security and environmental goals by 2050. The challenge requires improving intercrop performance for evolving designs where intercropping is not the dominant form of agriculture, such as the Midwestern U.S. This thesis examines the role of the aboveground ecophysiological mechanisms in maize (Zea mays L.) and soybean (Glycine max (L.) Merr.) intercropping systems on resource-use and productivity. This research further determined improved phenotypes by the development of a mechanistic functional-structural plant (FSP) model. The objectives of this research were to: 1) quantify light interception, photosynthetic capacity, and seasonal evapotranspiration (ET) under rainfed conditions for an additive alternate-row maize and soybean intercropping system to assess the potential for polyculture systems to improve water-use efficiency, 2) compare trait plasticity responses and light-use efficiencies under the solar corridor intercrop, solar corridor maize monoculture and the standard monoculture systems of the Midwest, 3) evaluate the recovery of the solar corridor monoculture and intercrop under three maize plant densities compared to the standard monoculture systems under multiple severe weather events and assess the temporal yield variability and land-use efficiency across two-site years, and 4) develop a mechanistic maize and soybean FSP model to disentangle the contribution of individual traits to yield and identify an improved maize and soybean phenotype for the solar corridor intercrop system. The findings presented here show that additive and simultaneous intercrop configurations involving maize and soybean have significant drawbacks in realising productivity and resource-use efficiency gains across biological scales. However, the context of these results reflects the importance of gaining a mechanistic understanding of the ecophysiological complexities regarding resource-use and phenotypic plasticity to improve intercrop performance. In addition, the improved maize and soybean phenotypes derived from FSP modelling in this thesis may guide breeding incentives (both traditional and transgenic) and cultivar selection in the future.

Graduation Semester

2021-08

Type of Resource

Thesis

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http://hdl.handle.net/2142/113169

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Copyright 2021 Elena Pelech

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