Are Soybean Seed-Applied Biostimulants Cost Effective In A Corn-Soybean Rotation?

 

A number of commercial soybean biostimulant products are available for seed application, with more products added annually. These belong to different chemistry classes (Lipochitooligo saccharide, hereafter referenced as LCO, anti-stress, hormonal, etc.), and the concentrations can differ greatly from product to product, especially in those products containing hormones such as gibberellic acid (GA), kinetin, and indole butyric acid (IBA). 

While most biostimulant products are strictly considered to only have biostimulant properties, some are actually hybrid products (inoculant + biostimulant), such as the LCO products (Optimize and Trident) and are often considered to be primarily inoculant products rather than hybrid products containing biostimulants.

 

Several growers have asked about these products, mainly, “Do seed-applied biostimulant products provide a consistent economic return, and if so, under what conditions?”

 

Over the past five years numerous replicated field trials involving both small plot and large commercial harvested plots were conducted across eastern Nebraska on both irrigated and rain-fed conditions to establish a large data set to answer these questions. While there have been a number of products evaluated in one or two field trials, only BioForge and Optimize have a robust data set for comparing their use under rain-fed and irrigated conditions. Each site shown had four replicated treatments with the exception of the David City 2011 site with Pioneer 93M11 soybeans, which had only three replications.

 

The majority of rain-fed plots were commercially planted (and combine harvested, weighed in weigh wagon, standardized to moisture), but the opposite was true for irrigated soybeans (small plots, etc.).

 

While a consistent trend for slightly higher yields was noted at every rainfed site (average of approximately 3.7%), no statistical increase in yield was noted at any single location. A paired t-test over all sites using the location yield mean noted that the two biostimulants used did result in a significant yield increase of 1.63 bushels/acre (50.3 vs.48.6 bu/acre, p<0.01).

 

Using a cash bid of $9.30/bushel for October 2016 delivered soybeans, and using the overall increase in bushels/acre of 1.63 bushels, this increased the value per acre in rainfed soybeans to $15.15/acre. Cost of each product/acre will be dependent upon amount of seed planted/acre (more seed = higher cost), as well as seed treatment costs. Using a minimum of $4/acre for product and another $2/100 pounds of soybean seed for application, these treatments created a net average maximum increase value of $9.15/acre. 

 

When examining data from irrigated soybean fields, the trend for increased yields associated with seed-applied biostimulants was not evident, with both positive and negative yields documented.   It should be noted that most of the irrigated data was derived using small plots and the variety was different than those utilized in the rainfed fields.