College of Agriculture & Natural Resources Department of Plant, Soil and Microbial Sciences

PLANT, SOIL & MICROBIAL SCIENCES 

Announcement of Final Thesis Defense

Crop and Soil Science M.S. Degree

Candidate’s Name:     Maria Kenneth Lane S. Bearss

Seminar/Examination Information: 

Date:               July 11, 2024
Time:              9:00 AM
Place:             A271 PSSB 

FOR ZOOM INFO CONTACT LAUREN COLBY

Title of Thesis 

UNDERSTANDING WINTER WHEAT AND SUGARBEET YIELD, GROWTH, AND QUALITY THROUGH INTENSIVE MANAGEMENT 

Members of the Examining Committee and their Department: 

1. Kurt Steinke - Plant, Soil and Microbial Sciences 
2. Martin Chilvers - Plant, Soil and Microbial Sciences 
3. Zachary Hayden – Horticulture

The seminar precedes the examination, at the time above 

ABSTRACT  

Increased global demand for small grains emphasizes the need for intensified management strategies and future yield gains. While nutrients and fungicides can individually improve winter wheat (Triticum aestivum L.) yield, the synergism between early and late-season fertilizer with multiple fungicide strategies is less understood. This study investigated the influence of various fertilizer and fungicide strategies and effects on winter wheat growth and development. Treatments were arranged as a full-factorial, randomized complete block design with two rates of autumn starter (AS), five fungicide timings (FT), and two rates of late-season nitrogen (LN) applied at Feekes 7 following both silage corn (SC) and soybean (SB). All treatments received a blanket N application [84 (SB) or 112 (SC) kg ha⁻¹] at Feekes 5, except for check plots. Following SC, AS increased mean grain yield by 2.2 Mg ha⁻¹ in 2022. The interaction of AS and FT significantly influenced grain yield in SC 2023. Across FT, AS consistently increased mean grain yield by 1.4 – 2.6 Mg ha^-1. Following SB, AS increased straw yield by 0.4, and 0.7 MT ha⁻¹, respectively in 2022 and 2023. An interaction between AS and LN significantly influenced straw yield with AS increasing straw yield both with and without LN application in SC 2022. Autumn starter fertilizer increased mean straw yield by 1.3 MT ha^-1 compared to no AS in SC 2023. The interaction of AS and LN significantly influenced grain protein content (SC 2023, SB 2022). Autumn starter decreased grain protein content when LN was not applied. Late-season N at Feekes 7 occasionally increased grain protein content (SC 2022 and SB 2023). Plant height was most correlated with grain yield while headcount and flag leaf S level were moderate modulators of straw production. Further, grain N was most correlated with grain protein content. Results emphasize the positive impacts that early-applied fertilizer can have on yield potential but changes in plant growth and development may impact grain quality.

Michigan sugarbeet (Beta vulgaris L.) nutrient management recommendations include 157-179 kg N ha^-1 with an initial 45 kg N ha^-1 applied at planting to promote canopy closure. While individually added inputs associated with yield gaps were previously investigated, synergistic influences when combined with a standard N program (SN) within an integrated management perspective have not been explored. This study investigated sugarbeet root yield and recoverable sucrose response to different fertilizer strategies along a stepwise increase in management intensity. In 2022, SN treatment averaged 90.1 Mg ha^-1, 148.4 kg Mg^-1, and 13,327.9 kg ha^-1. The addition of in-furrow P negatively impacted root yield and recoverable sugar by -15.5 Mg ha^-1 and - 2,325.7 kg ha^-1, respectively. In 2023, pre-plant broadcast lime, in-furrow P, and intensive management increased root yield by 13.7, 11.9, and 13.2 Mg ha^-1, respectively. The intensive management and pre-plant broadcast lime increased recoverable sugar per Mg by +7.1 and +8.4 kg Mg^-1, respectively, while also improving recoverable sugar per hectare by +2,329.8 and +2,278.0 kg ha^-1, respectively^. In-furrow P increased sugar per hectare by 2,186.3 kg ha^-1. The inconsistent root yield and recoverable sucrose response to marketed inputs accentuate the importance of pre-plant soil analysis, in-season weather monitoring, and the use of disease models for developing a climate-smart agricultural system.