Agronomic management to simultaneously increase yield and seed nutritional quality of soybean

Rampazzo Favoretto, Vitor

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https://hdl.handle.net/2142/115473 Copy

Description

Title

Agronomic management to simultaneously increase yield and seed nutritional quality of soybean

Author(s)

Rampazzo Favoretto, Vitor

Issue Date

2022-04-20

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

Below, Frederick E

Doctoral Committee Chair(s)

Below, Frederick E

Committee Member(s)

• Butts-Wilmsmeyer, Carolyn
• Mulvaney, Richard
• Heaton, Emily

Department of Study

Crop Sciences

Discipline

Crop Sciences

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

Soybean, Seed Protein, Yield, Sulfur, Inoculation, Glycine Max, nutritional seed quality, seed quality

Abstract

Soybean [Glycine max (L.) Merr.] is a major cultivated crop, providing protein and oil for human and animal feed. While soybean yields in the United States have increased over the years, seed oil concentrations have remained relatively constant while protein concentrations have decreased. This negative relationship between yield and seed protein, which hinders the commodity value for animal nutrition and U.S. soybean export, can be attributed to the combination of genetics, environment, and agronomic management. Modern soybean production has been focused only on higher yields. However, high-yielding and high seed protein soybean productions have been reported. Therefore, the objective of this research was to evaluate and determine agronomic management that could break the negative relationship between yield and seed protein concentration and increase yield and seed protein simultaneously. This research encompasses three research areas: Determine how fertilization with different sulfur sources affects yield and seed nutritional quality. Sulfur (S) fertilization of soybean increased soybean grain yield, with a higher protein variety being more responsive, especially when the environment allowed a high yield level. Applications at planting led to greater yields than in-season applications, but fertilization with more than 22.4 kg S ha-1 did not increase yields further. The availability of S throughout the season was the key factor influencing greater yields, with sources that provide season-long supply fostering more consistent yield results. The negative relationship between grain yield and seed protein concentration in soybean was broken by fertilizing with S, as simultaneous increases among the two measurements were observed. Lastly, the addition of S fertilizer resulted in higher cysteine concentration in the protein fraction of the seed, demonstrating that S fertilization can enhance the amino acid profile of soybean as a protein source for non-ruminants. Evaluate innovative nitrogen-fixation technologies in enhancing soybean grain yields and seed quality. Soybean inoculation can increase grain yield in the United States while maintaining seed protein level, depending on the environment and product used. Traditional seed inoculation with Bradyrhizobium japonicum increased soybean root nodulation, but only tended to increase grain yields when the plants were stressed. In contrast, combining new rhizobial strains and other beneficial microbes that also produce phytohormones increased soybean growth and resulted in numerically higher grain yields while preserving seed protein levels, indicating increased N accumulation from biological nitrogen fixation. Also, application methods that went beyond coating the seed, and instead focused on soil application of the inoculants showed evidence of being viable alternatives to the delivery of inoculant products, since those alternative placements of inoculants resulted in higher soybean grain yields. Explore the relationship between maturity group and release year of soybean varieties with grain yield and seed protein and how it changes in response to foliar protection and fertility. Soybean varieties were tested under different management, starting with standard management (0.76 meter between rows, 396,000 plants hectare-1). Then, a reduced row spacing, foliar protection (fungicide and insecticide at R3), fertilization (phosphorus and sulfur, or phosphorus, sulfur, potassium, and boron; applied at planting), and fertilization with foliar protection were added to the standard management. Later maturity soybean had higher grain yields, with a one-unit increase in maturity estimated to exhibit +295 kg ha-1 without decreasing seed protein concentrations under the standard management. However, plants grown at southern Illinois exhibited the weakest relationship between yield and seed quality. The response to management additions was independent of maturity group for grain yields and seed protein, implying that there was no need to change management practices for growing later maturity soybean. Newer varieties yielded more in response to foliar protection, and had lower seed protein concentrations. However, the year of release was poorly related to grain yields or the yield response to other management inputs. Lastly, adding foliar protection with phosphorus and sulfur fertility acted synergistically and led to increased grain yields while simultaneously generating higher seed protein concentrations, regardless of release year.

Graduation Semester

2022-05

Type of Resource

Thesis

Copyright and License Information

Copyright 2022 Vitor Rampazzo Favoretto

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