Agronomy and Horticulture Department


Date of this Version

Spring 4-1-2016


Stewart, Z.P., 2016. Micronutrient Foliar Analysis and Supplementation in Nutrient Management for High Yield Maize (Zea mays L.). Ph.D. Dissertation. Univ. of Nebraska, Lincoln.


A dissertation presented to the faculty of The Graduate College of the University of Nebraska in partial fulfillment of requirements for the degree of Doctor of Philosophy. Major: Agronomy, Specializations: Crop Physiology and Production / Soil Science. Under the Supervision of Professors Charles A. Shapiro and Timothy M. Shaver. Lincoln, Nebraska: May, 2016

Copyright © 2016 Zachary P. Stewart


Micronutrient supplementation in maize production is of growing interest to producers and agronomists as means to further increase yield as other crop needs are increasingly met. Plant tissue and soil sampling for micronutrient concentrations have been used to determine likely responses to micronutrient supplementation. Nebraska soils are generally micronutrient sufficient and usually do not have soil or plant tissue micronutrient concentrations below critical levels, however, during precise periods where specific micronutrients are in greatest need due to physiological demands, there may be opportunity for micronutrient supplementation to increase grain yield. The compiled chapters indicate that in most scenarios in Nebraska, foliar micronutrient supplementation is not likely to result in increased maize yield, and yield reductions may occur with micronutrient supplementation. However, grain yield increases can occur with micronutrient supplementation even when soil or plant tissue micronutrient concentrations are above critical levels (Chapter 3 and 4). Models are needed that consider factors in addition to soil and plant micronutrient concentrations for improved prediction of maize yield responses to applied micronutrients (Chapter 2). Additionally, the following chapters provide recommendations on target growth stages for foliar-applied micronutrients (Chapter 4), opportunities for precision application technologies with foliar-applied micronutrients in scenarios with confirmed micronutrient deficiency (Chapter 3, 4, and 6) ), an assessment of soil and plant micronutrient correlations and their relationship with grain nutrient densities (i.e. biofortification) (Chapter 2 and 4), and opportunities for nanomaterials to improve the efficiency of foliar-applied micronutrients (Chapter 5).

Advisors: Charles A. Shapiro and Timothy M. Shaver