Microbial Biostimulant Evaluation for Enhanced Phosphorus Availability in Corn and Soybean Production

Overview

This research program addresses a critical challenge in corn and soybean production: phosphorus (P) deficiency in soils. The project evaluates whether commercial microbial biostimulants can enhance the symbiotic relationship between arbuscular mycorrhizal fungi (AMF) and plant roots, thereby improving phosphorus availability for crop nutrition. Phosphorus is an essential nutrient for crop growth and soybean nodulation, yet it is relatively immobile in soil, making supplementation difficult and costly. By leveraging beneficial soil microorganisms, this research seeks to provide growers with biological alternatives or complements to conventional P fertilizer application, potentially reducing input costs while maintaining or improving yields.

The study focuses on two widely used commercial biostimulant products for corn (BioRise® and QuickRoots®) and two for soybean (TagTeam® LCO XC and Optimize® XC). The work is particularly relevant for operations on P-deficient soils where fertilizer efficiency is a concern, offering potential pathways to more sustainable nutrient management.

Technical specifications

Research design:

• Main treatments include a no-P control and P application based on soil testing recommendations
• Sub-treatments evaluate two biostimulant products per crop alongside an untreated control
• Rhizospheric soil samples (less than 1-2 mm) and root samples are collected from both corn and soybean

Key measurements and analyses:

• Soil available P assessed using the Mehlich-3 extraction test, a standard soil test method
• AMF root colonization quantified through microscopic examination of stained 1-cm root segments, with bleaching and staining reagents used to visualize fungal structures
• Leaf tissue P concentration analysis to determine plant nutritional status
• Crop yield measurement across all treatment combinations

Biological mechanism:

The research targets the symbiotic association where host plants supply carbohydrates to AMF, and the fungi in return mobilize otherwise immobile soil phosphorus for plant uptake. This natural partnership also supports soil aggregate formation, ecosystem function, and overall plant productivity.

Technology readiness level

This is an active field validation study at Technology Readiness Level 4-5 (component validation in relevant environment). The biostimulant products being evaluated are already commercially available, and the research aims to generate empirical evidence on their effectiveness under P-deficient soil conditions with and without P fertilizer application. Outcomes will provide growers and agronomists with data-driven guidance on integrating microbial biostimulants into nutrient management programs for corn and soybean production systems.