Plant Nutrient Interactions in High-yielding Soybean Environments

Authors

Victoria Inklman, University of Nebraska-LincolnFollow

First Advisor

Nicolas Cafaro La Menza

Committee Members

Jim Specht, Javed Iqbal

Date of this Version

8-2025

Document Type

Thesis

Citation

A thesis presented to the faculty of the Graduate College at the University of Nebraska in partial fulfillment of requirements for the degree of Master of Science

Major: Agronomy

Under the supervision of Professor Nicolas Cafaro La Menza

Lincoln, Nebraska, August 2025

Comments

Copyright 2025, Victoria Inklman. Used by permission

Abstract

Plant nutrient demands and limitations are usually studied individually by nutrient. Here, we investigated how nitrogen (N) limitation in high-yielding soybean environments affects the uptake, removal, and residual of other plant macro- and micronutrients. The objective of this study was to quantify the uptake, removal, and residual levels of soybean macro- and micronutrients under N-limited conditions and to identify nutrient priorities for high-yielding soybean systems. Aboveground plant samples at physiological maturity were collected in 19 high-yielding soybean fields with N limitation across the state of Nebraska. Reference plots with ample N supply were included within each field to compare macro- and micronutrient uptake, removal, and residual against a non-limited N condition. Plant samples were analyzed for macronutrients N, phosphorus (P), potassium (K), sulfur (S), magnesium (Mg), and calcium (Ca)—as well as micronutrients—zinc (Zn), manganese (Mn), iron (Fe), copper (Cu), boron (B), and molybdenum (Mo). Plant nutrient internal efficiency (NIE) and harvest index (NHI) of NPKS were calculated across fields and treatments to understand changes in total nutrient uptake, removal, and residual. The N limitation in high-yielding soybean environments reduced the total uptake and removal of N, K, and S, but did not affect P. Similarly, for the soybean residue, the N and S decreased, while P slightly increased and K remained unchanged under N limitation. The uptake of most micronutrients was also affected by N limitation. The NHI did not change for P, K, and S, but N limitation increased the fraction of plant N that was exported from the system with the harvested seed. The NIE was not affected by N and S, but NIE for P and K was reduced under N-limited conditions. Nutrient interaction results and their implications are discussed. These findings contribute to a balanced plant nutrition for high-yielding soybean crops.

Advisor: Nicolas Cafaro La Menza