Author ORCID Identifier:
Date of Graduation
7-2026
Document Type
Thesis
Degree Name
Master of Science in Crop, Soil & Environmental Sciences (MS)
Degree Level
Graduate
Department
Crop, Soil & Environmental Sciences
Advisor/Mentor
Drescher, Gerson
Committee Member
Kelley, Jason
Second Committee Member
Popp, Miachael
Third Committee Member
Roberts, Trenton
Keywords
Corn; Plant nutrition; Potassium
Abstract
Potassium (K) is a common yield-limiting nutrient in Mid-Southern U.S. corn (Zea mays L.) production, emphasizing the importance of effective diagnostic tools to support fertilizer decision-making. This study integrated two approaches to improve K management in irrigated corn systems: (i) evaluating K fertilization timing to identify in-season opportunities for correcting K deficiency, and (ii) developing a corn stalk-based diagnostic test to assess end-of-season K and nitrate-nitrogen (NO₃-N) status and fertilizer adequacy. Seven (2024-2025) and eight (2023-2024) field trials were conducted across Arkansas for the K application timing and stalk testing studies, respectively. For the K timing study, fertilizer-K (112 kg K ha-1) was applied either preplant or in-season (V6, V10, V12, V14, VT, and R2), along with a no-K control. Corn stalk samples (15- to 35-cm sections above the soil surface) were collected from fertilizer-K rate (0 to 187 kg K ha-1) response trials to quantify stalk-K and -NO₃-N concentrations at physiological maturity using deionized water and calcium chloride (CaCl₂) extractions. Corn was grown under furrow-irrigation on soils with varying K availability, and yield and selected yield components were measured at maturity. Across K-deficient environments, fertilizer-K applications during mid-vegetative stages (V10-V12) increased tissue-K concentration to levels comparable to preplant fertilization. Yield recovery was most consistent when K was applied before late vegetative stages (VT). No yield response to K fertilization was observed in soils with Medium and Optimum K availability. Kernel rows per ear were unaffected by K fertilization timing, whereas kernels per row and kernel weight increased with K fertilization at selected sites. End-of-season corn stalk testing showed water extractable K had a significant (P < 0.0001) relationship with relative yield (R² = 0.54) and enabled the definition of deficient (< 3,353 mg K kg⁻¹), optimum (3,353–7,142 mg K kg⁻¹), and excessive (>7,142 mg K kg⁻¹) stalk-K thresholds. In contrast, CaCl₂ extraction showed greater stalk-K concentrations but a lower correlation (R2 = 0.17) with grain yield, while remaining suitable for NO₃-N analysis. Integrating in-season K management strategies with end-of-season stalk diagnostics can improve nutrient use efficiency and support more informed fertilizer decisions in irrigated corn systems of the Mid-Southern U.S.
Citation
Andrade Leite Mengez, G. (2026). Potassium Fertilization Timing and Critical Stalk Potassium Concentration as Tools to Improve Corn Production. Graduate Theses and Dissertations Retrieved from https://scholarworks.uark.edu/etd/6323
