Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)

Department / School

Agronomy, Horticulture, and Plant Science

First Advisor

Peter Kovacs


Foliar Protection, Grain Protein, Grain Quality, Nitrogen, Soybean, Sulfur


Soybean [Glycine max (L.) Merr.] yield has increased over time by introduction of newer varieties and improved agronomic practices. However, grain protein concentration has been decreasing at the same time. New field studies in 2018 and 2019 investigated inseason crop management practices effect such as use of foliar protection application, fertilizer application, different maturity length or different planting dates on grain yield and grain quality. The studies were established near Brookings, SD and Beresford, SD. In-season treatments were targeting nutrient availability or protecting soybean canopy during the grain filling period. Such treatments included the use of fungicide, insecticide, or supplying additional nutrients through foliar applications at the beginning of grain fill of the soybeans. Nitrogen and S applications were also made at different timings either at pre-season, V4, and R3 growth stages. Biomass samples were taken at R5, R6, and R7 and partitioned into parts of the plant. Grain yield, grain protein concentration, and grain oil concentration were taken at harvest and analyzed. While foliar protection application or fertilizer treatment effects did not impact grain yield or seed composition, year, location, and maturity group often influenced these parameters. Applying what is needed for each field is important when trying to maintain grain yield and quality.

Library of Congress Subject Headings

Soybean -- Yields -- South Dakota.
Grain -- Quality -- South Dakota.
Field crops -- South Dakota.



Number of Pages



South Dakota State University



Rights Statement

In Copyright