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ARS Home » Plains Area » Bushland, Texas » Conservation and Production Research Laboratory » Livestock Nutrient Management Research » Research » Publications at this Location » Publication #434253
Research Project: Strategies to Manage Feed Nutrients, Reduce Gas Emissions, and Promote Soil Health for Beef and Dairy Cattle Production Systems of the Southern Great Plains

Location: Livestock Nutrient Management Research

Title: Effect of foliar biostimulants on soybean growth and yield across different tillage systems

Author
item THAPA, SUSHIL - West Texas A & M University
item GORDEN, RACQUEL - University Of Central Missouri
item SANTIAGO, MICHELLE - University Of Central Missouri
item Ortiz, Anna

Submitted to: Agronomy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/7/2026
Publication Date: 5/12/2026
Citation: Thapa, S., Gorden, R., Santiago, M., Ortiz, A.C. 2026. Effect of foliar biostimulants on soybean growth and yield across different tillage systems. Agronomy. 16(10). Article 958. https://doi.org/10.3390/agronomy16100958.
DOI: https://doi.org/10.3390/agronomy16100958

Interpretive Summary: Commercial products that can improve crop yields are called biostimulants. Studies show that biostimulants can improve how crops grow, handle unpredictable weather, and can even reduce how much fertilizer is needed. Scientists from the University of Central Missouri, West Texas A&M University, and the USDA-ARS in Bushland, Texas studied the effects of a crop nutrient (phosphorus) and a biostimulant on soybean in the field and in a greenhouse. They found that soybean plants respond better to the biostimulant and produce more seed regardless of how much soil is ploughed. They also found that soybean plants in Missouri do not grow better when a biostimulant is used at the same time as phosphorus. This research helps soybean farmers by highlighting that they do not need to invest in both phosphorus nutrients and biostimulants to improve yield.

Technical Abstract: Climate variability and widespread synthetic agrochemical use have increased interest in biostimulants (BS) that enhance plant growth, stress tolerance, and yield by stimulating natural plant processes. A two-site field study, under no-till and tilled systems, evaluated the effects of foliar biostimulant “Source” on soybean growth and yield at three phosphorus (P) rates (0%, 50%, and 100% of soil test recommendations). A complementary greenhouse study was conducted to evaluate the effect of biostimulant on different soybean hybrids. Measured at various dates after planting (DAP), leaf relative water content (LRWC) and normalized difference vegetation index (NDVI) mostly showed insignificant responses to P treatments, but significant response to BS. Grain yield increased significantly with individual BS and P applications in both tillage systems. Under no-till, BS increased yield by 13.0% (3.05 vs. 2.70 Mg/ha), and P100 increased yield by 13.5% (3.0 vs. 2.65 Mg/ha). Under tilled conditions, BS and P100 increased yield by 19.6% (2.75 vs. 2.30 Mg/ha) and 19.2% (2.72 vs. 2.28 Mg/ha), respectively, compared with the control. Yield gains were primarily driven by increased pod density and grain number. Greenhouse experiments supported these trends, with BS-treated plants producing more grains per plant (187.6 vs. 171.3) and higher yield per plant (28.8 vs. 25.7 g). Results indicated that biostimulant application improved physiological performance and sustained soybean yields comparable to full-rate P, highlighting its potential as a more sustainable approach under increasing environmental and input-related challenges.