Degree Type

Creative Component

Semester of Graduation

Spring 2019



First Major Professor

Mark Licht


Master of Science (MS)




One of the biggest issues with ultra-early planting of soybean [Glycine max (L.) Merr.] is the lack of research that has been conducted. This study is designed to increase the knowledge base of soybean planting dates by looking at ultra-early (March) versus early (April) planted soybean in south-central Illinois. Field research was conducted in two fields, near Morrisonville, IL over the 2017 and 2018 growing season. In 2017, the March planted soybean required 19 days to gain 121 GDD for emergence to start. Compared to the April planting date where emergence was in 7 days with 123 GDD accumulation. In 2018, it took 38 days and 122 GDD for the March planted soybean to start emergence. In comparison, the April planting had emergence in 11 days at 125 GDD accumulation. There was no significant grain yield difference (p = 0.7090) for soybean planted in March compared to soybean planted in April. Overall, the mean grain yield for the March planting date was 89.02 bu/acre while mean grain yield for the April planting date was 89.25 bu/acre over the course of a two year period. The biggest influence on grain yield was year over the two year period (p < 0.001). Yet, not when we look at variety by year interaction (p = 0.2852). In conclusion, this study found that, planting soybean ultra-early, March, compared to early, April, did not increase yields.

Copyright Owner

Marley, Nicholas

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