2024
Evaluating Leaf Nutrient Tissue Testing and Relation to Soybean Grain Yield
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Contributor/Checkoff:
Illinois Soybean Association
Category:
Sustainable Production
Keywords:
Fertilizer/plant nutrientField management
Parent Project:
This is the first year of this project.
Lead Principal Investigator:
Fred Below, University of Illinois at Urbana-Champaign
Co-Principal Investigators:
Connor Sible, University of Illinois at Urbana-Champaign
Project Code:
Contributing Organization (Checkoff):
Illinois Soybean Association
$79,123
Institution Funded:
University of Illinois at Urbana-Champaign
$79,123
Brief Project Summary:
The use of in-season foliar applications of nutrients has started to increase across soybean production acres in pursuit of higher yields and improved grain quality. Application decisions are often determined through use of a tissue test of the most-recently opened trifoliate. Soybean exhibits an indeterminate growth pattern where the lower nodes start to remobilize nutrients to developing pods at the same time new nodes and leaves are still emerging at the top of the plant. There is a knowledge gap in the understanding of when certain nodes initiate nutrient remobilization to the grain, and if the standard tissue testing approaches can accurately assess nutrient deficiencies at the whole...
Information And Results
Project Summary

The use of in-season foliar applications of nutrients has started to increase across soybean production acres in pursuit of higher yields and improved grain quality. Application decisions are often determined through use of a tissue test of the most-recently opened trifoliate. Soybean exhibits an indeterminate growth pattern where the lower nodes start to remobilize nutrients to developing pods at the same time new nodes and leaves are still emerging at the top of the plant. There is a knowledge gap in the understanding of when certain nodes initiate nutrient remobilization to the grain, and if the standard tissue testing approaches can accurately assess nutrient deficiencies at the whole plant level. This research proposes to identify when during a soybean plant’s life cycle temporal and positional nutrient deficiencies or sufficiencies occur and if current methods of tissue sampling accurately determine in-season nutrient application needs.

Project Objectives

A replicated small-plot field study will be conducted with two levels of fertility, none (deficient) or full rate of nitrogen, phosphorus, potassium, sulfur, zinc, and boron (sufficient). Whole leaf samples at paired nodes will be assessed for both nutrient concentration and accumulation at different growth stages throughout the season. At maturity, yield will be assessed at the nodal and whole-plant levels. Final grain yield, mineral nutrient accumulation, and grain quality (protein and oil) at each node pair will also be determined.

Project Deliverables

Results of this research can be used to better identify when leaf tissue testing should be performed to identify the need for managing foliar nutrient applications to soybean production fields for greatest application efficiency, grain yield, and grain quality. Pairing unfertilized to fertilized plots can best assess when nutrient deficiencies occur.

Progress Of Work

Final Project Results

Benefit To Soybean Farmers

Farmers will know when leaf tissue testing should be performed to identify the need for managing foliar nutrient applications to soybean production fields for greatest application efficiency, grain yield, and grain quality.

The United Soybean Research Retention policy will display final reports with the project once completed but working files will be purged after three years. And financial information after seven years. All pertinent information is in the final report or if you want more information, please contact the project lead at your state soybean organization or principal investigator listed on the project.