Resources that Help Sustainable-Organic Vegetable Growers Select, Use, and Evaluate Microbe-containing Crop Stimulants (MCCSs) More Effectively

Final report for LNC16-380

Project Type: Research and Education
Funds awarded in 2016: $198,842.00
Projected End Date: 01/15/2021
Grant Recipient: Ohio State University
Region: North Central
State: Ohio
Project Coordinator:
Matthew Kleinhenz
The Ohio State University-OARDC
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Project Information

Summary:

Plant-associated microbes can significantly impact crop production. Many microbes are now included as leading components of microbe-containing crop stimulants (MCCSs) advertised to enhance soil and crop health, accelerate soil nutrient cycling, and improve crop quality, among other benefits. Therefore, MCCSs appeal to ever-greater numbers of sustainable-organic farmers (SOFs). The challenge, however, is that MCCSs are numerous, diverse, and often expensive to apply. Also, most MCCS labels offer little help when selecting or using products. Worse, objective, user-oriented, and research-based resources used by SOFs and their advisors rarely include information on MCCSs. SOFs and their advisors would clearly benefit from resources for selecting, using, and evaluating the benefits of MCCSs. For MCCSs, we have: a) assessed use by growers; b) synthesized available information and incorporated it into widely-available, user-friendly, and enthusiastically-received resources; and c) completed pilot on-station and on-farm studies. Evidence points to an urgent need to expand and strengthen this process, thereby preparing SOFs and their advisors to address significant and recurring questions about MCCSs now and going forward. We will partner with SOFs, organizations, MCCS manufacturers, and extension-research colleagues to develop technically rigorous, consensus-based, and user-oriented educational and decision-making resources. We will demonstrate a replicable process for evaluating MCCSs that minimizes guess-work in selecting and using them and evaluating their economic benefits. Experiments will address questions about inoculant-crop-production setting combinations and inoculation timing and rate. Team and grower-chosen MCCSs (single-species, single-genus multi-species, multi-genera) will be applied to butternut squash, carrot, lettuce, spinach, and tomato grown on sustainable-organic farms and at the Ohio Agricultural Research and Development Center. Inoculation timing and rate treatments will be tested in individual experiments during the crop cycle (e.g., before seeding, during transplant production, after transplanting). Similar experiments will be completed in open fields, and under low-, mid- and high tunnels. Microbial colonization and crop development and productivity will be tracked from seeding through harvest; crop yields and MCCS costs will be included in economic models. Farmer experiences with MCCSs will also be documented and summarized. Material, digital, and human networking resources will insure that new research-based information is widely available in user-friendly formats. Overall, we will improve farmers’ immediate capacities to sensibly and reliably integrate MCCSs into their toolboxes while also fostering durable gains in farmers’ on-farm research skills and in resources educators can apply in serving SOFs.

Project Objectives:

We will work to limit the very significant challenges SOFs face in making the best use of MCCSs by:
1) Using crop and financial metrics to comprehensively evaluate MCCSs at The OSU and on farms;
2) Expanding and strengthening a growing network of farmers, MCCS manufacturers, scientists, educators, and
consultants engaged in evaluating and reporting on MCCS performance; and
3) Establishing, sharing, and helping stakeholders implement core components of user-centered guidelines for the
best practical use of MCCSs on sustainable-organic farms.

We will achieve two goals by project end.

First, we will have described the effects of numerous MCCSs – for the
first time – objectively, for a wide audience, and specifically to address growers’ concerns.

Second, by establishing teams of trained evaluators and teachers representing the best of farmer and extension-scientist capacities, we will have prepared SOFs and others to select, use, and evaluate these products much more reliably in the future, with special emphasis on cost-effectiveness.

Our primary research objective is to use crop and financial metrics to comprehensively evaluate MCCSs at The OSU and on farms. Increasing SOF access to high quality, high priority, and ready-to-use information from these evaluations will help them earn greater returns on their investments in MCCSs. Further, a network of farmers, researchers, manufacturers, and others will join in creating, disseminating, and helping stakeholders use MCCSs more reliably. We propose to test six products differing in manufacturer, composition, crop host, and the extent to which we and growers have experimented with/used them.

Cooperators

Click linked name(s) to expand
  • Dr. Subbu Kumarappan
  • Dr. Christopher Taylor

Research

Materials and methods:

On-station experiments were completed at OSU’s OARDC in Wooster, OH using two warm season fruiting crops (butternut squash and tomato) and three cool season leaf and root crops (carrot, lettuce, spinach), in certified organic or transitional sites in open field and high tunnel settings.  Crops were planted in spring, summer, and fall and managed using certifiable organic practices. These experiments tested six different microbial biostimulant products applied at specific crop development stages (timing) or at different rates (rate) based on manufacturer recommended rate. Only timing was used as a factor in high tunnel experiments while timing and rate were factors in field experiments. Experiments completed on-station are outlined in Table 1. Experimental factors are summarized in Table 2. Brief narratives of experiments are provided after Table 2.

Table 1. Experiments completed on-station (OARDC, Wooster, OH), spring 2017-fall 2019

Year

Planting season

Experiment

Crops*

2017

spring

timing

carrot (T), lettuce (O), spinach (T)

summer

rate, timing

butternut squash (O, T), tomato (O, T)

fall

timing

lettuce (T), spinach (T)

2018

spring

timing

carrot (T), lettuce (O), spinach (T)

summer

rate, timing

butternut squash (O, T), tomato (O, T)

fall

timing

carrot (T), lettuce (T), spinach (T)

2019

spring

timing

carrot, (T), lettuce (O), spinach (T)

summer

rate, timing

butternut squash (O, T), tomato (O, T)

fall

timing

carrot (T)

*(O) is a certified organic site, (T) is a site in transition to organic

 

Table 2.  Summary of experimental factors (product x timing, product x rate)

 

 

 

 

 

High Tunnel (spring and fall)

Field (summer)

carrot

lettuce

spinach

butternut squash

tomato

 

control

x

x

x

x

x

timing

transplants

at transplant

 

  x**

 

x

x

at 2 weeks after transplant

 

x

 

x

x

at 4 weeks after transplant

 

x

 

x

x

direct seeded

after seeding, before emergence

x

 

x

   

at 1 week after 50% emergence

x

 

x

   

at 3 weeks after 50% emergence

x

 

x

   

rate

 

0.5x label recommended rate

     

x

x

1.0x label recommended rate

     

x

x

1.5x label recommended rate

     

x

x

products

 

Environoc® 401 (Biodyne® USA)

 

x

x

x

x

EcoFungi (EcoMicrobials™)

x

   x****

 

x

x

MycoApply® All Purpose (Mycorrhizal Applications)

x

   x***

x

x

x

MycoApply® Endo Maxx (Mycorrhizal Applications)

x

x

 

x

x

MycoApply® Soluble Maxx (Mycorrhizal Applications)

 x*

x

     

BioGenesis I™ NP (Tainio® Biologicals, Inc)

x

x

x

x

x

MycoGenesis™ (Tainio® Biologicals, Inc)

x

x

x

x

x

* MycoApply® Soluble Maxx substituted for MycoApply® All Purpose in fall 2019 carrot experiment due to discontinuation of product.

** Spring 2018 and 2019 lettuce experiments did not include timing “at 2 weeks after transplant”.

*** Fall 2017and 2018 and spring 2018 and 2019 lettuce experiments did not include this product.

****Spring 2018 and 2019 lettuce experiments did not include this product.

High Tunnel Experiments

1) Carrot (Spring 2017; Spring and Fall 2018; Spring and Fall 2019)

One high tunnel (30’ x 80’, transitional) was hand-seeded with pelleted organic ‘Mokum’ carrot into (20) 12’L x 4’W x 1.5’H wood-framed raised beds to test the application of five different microbial biostimulant products (BioGenesis I™ NP, EcoFungi, MycoApply® All Purpose, MycoApply® Endomaxx, and MycoGenesis™) at three different stages of crop development (after seeding/before emergence, 1 week after 50% emergence, or 3 weeks after 50% emergence) with a control of no product application at any time. A randomized complete block design was used with four replications. Soil in raised beds was composed of loam silt field soil, Pro-Mix BX, dairy manure compost, and horticultural grade perlite and vermiculite. All raised beds were seeded with four rows, 2” in-row and 12” between row spacing. Each raised bed in a replication was assigned a single product and contained 4 plots (4’ L x 3’ W), one control and one each receiving treatment at a specified timing. Seedling stand counts were completed after emergence to determine when 50% emergence had been achieved. The crop was drip irrigated. No pest or disease controls were applied during the experiment. Carrots were harvested once with the following data collected: total count, total biomass, root and crown weight, and cull reasons; individual weight, root length, shoulder and tip diameters, internal and external colorimeter readings of 3 subsampled marketable roots per plot; % dry matter of roots and °Brix on halves of 3 subsampled marketable roots, aggregated.

*MycoApply All Purpose was discontinued by the manufacturer. MycoApply Soluble Maxx was used in the Fall 2019 experiment.

2) Lettuce

Lettuce experiments varied in the number of products and timings used across seasons and years. This variation was due to high tunnel availability and differences in high tunnel size. Each experiment maximized the number of products and timings that the size of the high tunnel could accommodate. 

A. Spring 2017 included application of all six products at all three timings

Two high tunnels (21’ x 48’ each, certified organic) were planted with six-week old organic ‘Parris Island’ transplants to test the application of six different microbial biostimulant products (BioGenesis I™ NP, EcoFungi, Environoc 401®, MycoApply® All Purpose, MycoApply® Endomaxx, and MycoGenesis™) at three different stages of crop development (at transplant, 2 weeks after transplant, or 4 weeks after transplant) with a control of no product application at any time. Three products were tested in each tunnel. A completely randomized design was used with four replications. Each high tunnel was planted with four rows (6” in-row and 8” between row spacing) per replication. The crop was transplanted into flat, Wooster silt loam bare soil and drip irrigated. Each plot (3’ L x 4’ W) received treatment at a specified timing or a control of no application. No pest or disease controls were applied during the experiment. Lettuce was harvested once with the following data collected: fresh weight of 3 marketable heads, leaf area, % dry matter of leaves, and °Brix.

B. Spring 2018 and 2019 included application of four products at two timings

One high tunnel (21’ x 48’, certified organic) was planted with six-week old, organic ‘Parris Island’ transplants to test the application of four different microbial biostimulant products (BioGenesis I™ NP, Environoc 401®, MycoApply® Endomaxx, and MycoGenesis™) at two different stages of crop development (2 weeks after transplant or 4 weeks after transplant) with a control of no product application at any time. A randomized complete block design was used with four replications. Each replication was planted with four rows (6” in-row and 8” between row spacing) per replication. Products were applied at their specified timings. The crop was transplanted into raised, Wooster silt loam bare soil and drip irrigated. Each plot (3’ L x 4’ W) received treatment at a specified timing or a control of no application. No pest or disease controls were applied during the experiment. Marketable lettuce plants were harvested once with the following data collected: total count, total fresh weight; fresh weight of plant, leaves, leaf area, % dry matter of leaves, colorimeter readings, and °Brix were collected for 3 individual subsampled plants from each plot.

C. Fall 2017 and 2018 included application of five products at all three timings

One high tunnel (30’ x 80’, transitional) was planted with 5-7 week old, organic ‘Parris Island’ transplants into (20) 12’L x 4’W x 1.5’H raised beds to test the application of five different microbial biostimulant products (BioGenesis I™ NP, EcoFungi, Environoc 401®, MycoApply® Endomaxx, and MycoGenesis™) at three different stages of crop development (at transplant, 2 weeks after transplant, or 4 weeks after transplant) with a control of no product application at any time. A randomized complete block design was used with four replications. All raised beds were planted with six rows (6” in-row and 8” between row spacing). Each raised bed in a replication was assigned a single product and contained 4 plots (4’ L x 3’ W), one control and one each receiving treatment at a specified timing. The crop was drip irrigated. No pest or disease controls were applied during the experiment. Soil in raised beds was composed of loam silt field soil, Pro-Mix BX, dairy manure compost, and horticultural grade perlite and vermiculite. Marketable lettuce plants were harvested once with the following data collected: total count, total fresh weight; fresh weight of plant, leaves, leaf area, % dry matter of leaves, colorimeter readings, and °Brix were collected for 3 individual subsampled plants from each plot.

3) Spinach

One high tunnel (30’ x 80’, transitional) was seeded with organic ‘Regiment’ spinach using a Jang JP-3 three-row push seeder to test the application of four different microbial biostimulant products (BioGenesis I™ NP, Environoc 401®, MycoApply® All Purpose, and MycoGenesis™) at three different stages of crop development (after seeding/before emergence, 1 week after 50% emergence, or 3 weeks after 50% emergence) with a control of no product application at any time. A randomized complete block design was used with six replications. Each 60’ replication was seeded to four rows with a target 2” in-row and 8” between row spacing; however, in-row seeding rates were inexact and varied due to imprecision of seeder. The crop was seeded into Wooster silt loam bare soil and drip irrigated. No pest or disease controls were applied during the experiment. Products were applied to plots (3.5’L x 2.67’ W) at their specified timings with seedling stand counts completed to determine when 50% emergence had been achieved. Spinach leaves were harvested once for spring plantings and twice in fall plantings, which over-wintered. The following data was collected: total marketable fresh weight, % dry weight of leaves, leaf area, and °Brix.

Field Experiments

Butternut Squash and Tomato (Summer 2017, 2018, 2019)

One organic field (210’ x 185’) and one transitional field (210’ x 150’ in 2017; 210’ x 185’ in 2018, 2019) were planted with tomato (‘BHN 589’) and butternut squash (‘Metro PMR’) transplants (six and five weeks, respectively) in June. Rate and timing experiments were conducted on both crops in both fields for a total of eight experiments each year. The timing experiment tested the application of six different microbial biostimulant products (BioGenesis I™ NP, EcoFungi, Environoc 401®, MycoApply® All Purpose, MycoApply® Endomaxx, and MycoGenesis™) at three different stages of crop development (at transplant, 2 weeks after transplant, or 4 weeks after transplant) with a control of no product application at any time. The rate experiment tested the application of the same products at three different application rates (0.5x, 1.0x, and 1.5x the recommended manufacturer rates) with a control of no product application, applied on or the day after transplant. Crops were waterwheel transplanted, adding one gallon 2-4-1 fish fertilizer to 100 gallons of transplant water, into plastic covered raised beds, Wooster silt loam field soil, with drip irrigation. Ground cover was used in the organic field and pre-emergent herbicides in the transitional field to control weeds between the beds. A split-plot randomized complete block design was used with four replications, 3 rows per replication. Each 100’ raised bed row was planted with a single row with 2’ in-row spacing, and 6’ centers, individual plots measuring 12’ l x 3’ W. Plantings were fertigated weekly beginning mid-July through harvest with fish hydrolysate (15-2-0.5) and liquid calcium (5%). Weekly rotations of pest and disease controls were applied during the experiment until harvest.

Butternut squash was harvested once in both fields with the following data collected: total weight and fruit count, marketable fruit weight and count, primary reason to cull for marketability; individual fruit weight, length and width, internal colorimeter, % dry matter of fruit, and °Brix were collected from three subsampled fruit per plot.

Tomatoes were harvested two-five times each season with the following data collected: total weight and fruit count, green fruit weight and count (final harvests only), marketable weight and fruit count, primary reason to cull from marketability; pH, titratable acidity, and °Brix were collected from three subsampled fruit per plot at least once per season.

On Farm Evaluations

On-farm evaluations were conducted each growing season by a combination of new and repeating farmers. Growers transitioning to organic or organically certified were invited to participate in on-farm evaluations to utilize one of six pre-selected microbial biostimulants or a biostimulant of choice, if they grew:

  1. one of five crops (butternut squash, carrot, lettuce, spinach, tomato)
  2. in field or high tunnel
  3. in the Northcentral and Great Lakes States

Growers were recruited through direct outreach and collaboration with the Ohio Ecological Food and Farming Association via mailers and publishing of articles in quarterly newsletters. Project staff worked with each grower to determine crop, product, treatments, experimental design, and agree upon expectations for return of observations and yield data, when possible. Product (if one of the six pre-selected for study on-station and on-farm) was donated by manufacturers and shipped to growers. Project staff and growers stayed in communication during the season of evaluation by phone, email, and/or mail. Growers who completed an evaluation were provided a $250 stipend. A summary of on-farm evaluation is in Table 3.

Table 3. On-farm Evaluation Summary

 

2017

2018

2019

# interested/recruited growers

10

11

2

# of states

6

5

1

States

IA, IL, MI, MO, OH, PA

IA, MI, MO, PA, OH

OH

Crops planned for evaluation

Butternut squash, lettuce, spinach, tomato

Butternut squash, carrot, spinach, tomato

Lettuce, carrots

Products planned for evaluation

Biogenesis, Environoc 401, MycoApply All Purpose, MycoApply EndoMaxx, Mycogenesis

Biogenesis, EndoMaxx, Environoc 401, MycoApply All Purpose, Mycogenesis

EcoFungi, MycoApply Endo

Growers able to complete evaluations

5 (IA, MI, MO, OH, PA)

7 (IA, MI, PA, OH)

2 (OH)

Details about planting area, including size and management (irrigation, mulch, amendments, pest/disease control), observations of the crop throughout the growing season in writing and/or in photos (comparing treated to untreated), perceived ease of use of product/application, and data (predominantly yield) were collected by growers and provided to the project team. 

Through conversations with product manufacturers and growers, the project team continually assessed strategies to best assist growers to successfully set-up and complete on-farm evaluations. Several growers experienced challenges and were unable to complete their evaluations as expected. Examples of these challenges include inability to disentangle butternut squash vines to treatment plot; over commitment and inability to work into schedule; getting behind and not planting the variety of crops or quantity of crops expected; crop failure.

Research results and discussion:

On-station experiments:

On-station experiments were repeated each season during the grant cycle: fall and spring high tunnel timing experiments with carrot, lettuce, and spinach and summer field timing and rate experiments with butternut squash and tomato. Together, these experiments represent a total of thirty-nine runs of eleven individual experiments, each containing 32-72 inoculated plots. The body of work included a total of 899 and 1650 inoculated plots across the high tunnel and field experiments, respectively with all groups/replicates of inoculated plots containing non-inoculated control plots. As such, data collected on a per-plot basis allow various statistical approaches to be used in assessing the effects of product application (crop inoculation) and data analysis continues.

To date, outcomes from standard statistical approaches common in product evaluations, variety trials, and cultural management comparisons (e.g., analyses of variance, direct comparison of replicate means) show that significant increases in yield or quality were rare, regardless of inoculation parameters or experimental conditions. When found, yield increases were most common following the application of mixed inocula (single products containing multiple species or strains of bacteria, fungi, or both) and typically below eight percent. Also, although season-season variation in treatment outcomes limited the opportunity to identify a single best-performing product across all experiments regardless of setting or crop, outcomes of means comparison tests to date suggest that inoculation can increase yield in all crops and both settings tested but to extents cautioning against its routine recommendation, particularly without preexisting information.

Indeed, additional ongoing analysis currently includes two approaches already informing following-up research and extension and and conclusions possible from data collected during this project. In one approach, the yield value of each inoculated plot was divided by the yield value of the control plot located in the same replicate. This process resulted in 899 and 1650 I/NI (inoculated/non-inoculated) values for the high tunnel and field experiments, respectively. We noted that 54% and 50% of all I/NI values exceeded 1 in the high tunnel and field experiment group, respectively. Further, mapping all I/NI values revealed possible trends in the distributions of values greater and less than 1, suggesting patterns in undocumented edaphic and other factors influenced inoculation outcomes. Statistical analysis of these potential spatial relationships is underway along with a review of edaphic and experimental factors that may have contributed to recorded observations. In the second approach, data are being analyzed following transformation and using tests common in other areas of study in which skewed (including physical distribution) data are common (e.g., pathology, entomology, weed science). Ongoing economic analyses exploring the return on investment from microbe-containing crop biostimulant is accounting for experiment-experiment variation in yield responses across crops and employing observed and hypothetical yield, cost, and price (revenue) data.

On-farm evaluations:

 In total, seventeen unique farmers in six states began at least one season intending to complete evaluations; nine farmers in five states were able to complete evaluations and submitted observations and/or harvest data.  Participants noted three primary areas of interest: a desire to 1) learn about microbial biostimulants first-hand, 2) the relationship of soil ecology to soil health, and 3) the role of healthy soil in producing healthy plants. 

For those able to complete evaluations, on-farm results have been consistent with findings on-station. Single factor ANOVAs performed on yield data from a subset of growers have not shown statistically significant results comparing treatment to control. Anecdotally, growers continue to have interest in using microbial biostimulants, noting interest in continuing to understand the role stress, weather conditions, soil, crop-product interactions, and single season versus results over time have on outcomes.

Participation Summary
17 Farmers participating in research

Project Activities

Considering crop biostimulants, biofertilizers?
Call-in conversations offered on microbe-containing biostimulants and biofertilizers
New resources available on microbe-containing bisotimulants and biofertilizers (MCBSFs)
Biostimulants and biofertilizers: Their role in organic production
Our Bugs in a Jug Webpage - Ohio State University
Get your money's worth from crop biostimulants/biofertilizers that contain microbes
So many products, so little information, so much confusion
Dozens of trials over thousands of miles
A way forward: A team approach to increasing grower success with MCBSFs
Larger, better, and more stress-tolerated crops with microbial biostimulants?
Microbials, grafting, strip tillage, and soil balancing
Microbial biostimulants in grower toolboxes
Can microbial inoculants (biostimulants) enhance vegetable yield and/or quality?
Grafting and microbial crop biostimulants on early growth of greenhouse tomato
Getting the most from microbe-containing crop biostimulants
Microbial-based biostimulants: Grower, supplier, and researcher perspectives on their use in vegetable production
U.S growers cautiously optimistic about biostimulants
Microbial-based biostimulants: Big potential in small packages
Towards the best practical use of microbial-based biostimulants in vegetable production
What is in your microbial-based crop fertilizer?
Microbial biostimulants: Their place in the toolbox
Big questions about microscopic crop (and grower?) partners
Crop microbial biostimulants: What, why, and how?
Microbials overview and next steps
Microbe-containing crop biostimulants: What we know, what is important to learn
Microbials summary and discussion
Microbial biostimulants overview
Microbes in your toolbox? Let's talk
Biostimulants: What are they and how can I make them work for me?
Selecting microbial-based biostimulants/biofertilizers using a farm-centered approach
Big claims, big questions
Using microbial-based biostimulants/biofertilizers: tactics to maximize their potential benefits
Evaluating the value of microbial-based biostimulants/biofertilizers on your farm
Researchers Share Five “Fast Facts” to Help Growers Understand Biofertilizers
Progress through private-public sector partnerships: issues and approaches
Key steps, including on-farm evaluation, in getting the most from biostimulants
Improving labels: an important step in advancing the use of crop biostimulants
Assessing the Influence of Microbe-containing Crop Biostimulants on Vegetable Crops and Farms through On-station and On-farm Study
OSUE Wayne County IPM scout training
Fruit Yield and Quality in a Strip Till Tomato Systems as Influenced by Grafted Plants and Crop Biostimulants
Understanding biofertilizers
Microbe-containing crop biostimulants in the farming toolbox
Biostimulant science and application
Development and utilization of microbe-containing biostimulants for vegetables
Microbe-containing crop biostimulants in organic vegetable production: lessons and messages from farmers, researchers, and manufacturers
Research newly completed and started
Muck Crops Research-Extension Breakfast Meeting
Muck Crops Research-Extension Breakfast Meeting
Making up lost ground (actually, for lost plants or leaves)
Harvests of data hopefully increase harvests of money
From new and unusual to common (or maybe not): the dynamic world of specialty varieties
What are biostimulants?
Microbial Inoculants in VegPro Listserv
Tips for Using Microbial-based Products
Microbe-containing Crop Biostimulants in Vegetable Production: Product Expectations and Evaluation Statistics Driving Next-Generation Res and Ext
Should I Use Microbe-containing Crop Biostimulants? Inoculation Effects on Tomato Fruit Yield and Quality
An Overview of Microbe-containing Crop Biostimulants
Current, Key Information on Microbe-containing Crop Biostimulants
What to Know about Microbe-containing Crop Biostimulants
Microbe-containing Crop Biostimulant Primer
What works best? Studies of biostimulants address questions.

Educational & Outreach Activities

200 Consultations
15 Published press articles, newsletters
21 Webinars / talks / presentations
4 Workshop field days
6 radio/podcast interview, list serv, blog post, calendar listing on website

Participation Summary

800 Farmers
200 Ag professionals participated
Education/outreach description:

A combination of traditional education and outreach activities and resources (e.g., articles, presentations, webpages, blog posts, online databases and references, field days, individual and small group consultations, responses to spontaneous requests for information by phone an email) combined with less traditional activities (call-in conversations, radio interviews) to reach those currently using and newly interested in crop biostimulants. Regardless of medium and approach, the goal was to improve stakeholder overall familiarity with microbe-containing crop biostimulants as an input category and stakeholder confidence in and success at selecting, using, and evaluating the effects of these products.

Project Outcomes

Key practices changed:
    14 New working collaborations
    Success stories:

    1. Microbe-containing crop biostimulants have long been mysterious, questioned, and maligned in some technical and industry communities while also being very popular and lucrative in others. However, some engaged by the project (e.g., grower organizations, agricultural media) were initially unfamiliar with key issues surrounding the selection, use, and evaluation of microbe-containing crop biostimulants. This project helped establish productive dialogue among those directly impacted by product selection, use, and evaluation while also raising interest among those without stakes in these processes but prepared to assist in their improvement in technical and other ways. Regardless, continued dialogue regarding product selection, use, and evaluation will provide short- and long-term benefits.

    2. This project focused on initiating the development of best practices for selecting, using, and evaluating the effectiveness of microbe-containing crop biostimulants, a process possibly unaddressed systematically until now. While complete and detailed best practices were not established by project end, significant progress in their development was achieved. Importantly, aided by project activities and input from others, factors to consider in product selection, use, and evaluation were identified. Similarly, key steps in employing these factors in decision-making were also identified.

    3. This project helped demonstrate that multi-year, institution, and disciplinary, and stakeholder-focused research and extension efforts focused on improving overall success with microbe-containing crop biostimulants are: a) possible, b) needed, and c) able to help catalyze and inform additional related efforts. Interest in project information was consistently high across research, extension, and industry communities.

    4. Evaluating the efficacy of and returns on investment from using microbe-containing crop biostimulants is challenging for all involved in the product development and supply chain, researchers, educators and farmer advisors, and, most importantly, farmer stakeholders. Biological, procedural, “attitudinal,” and other factors complicate the process. Product composition and effects on crop yield can be unclear and reaching consensus on reasonable expectations for product application effects can be difficult. For example, should inoculation increase yield measurably (statistical significance) in a clear majority of cases, regardless of cropping situation and setting or is it best thought of as protecting against yield losses, especially when growing conditions are sub-optimal? What is an acceptable ‘failure rate’ for these products? This project succeeded in catalyzing active discussion on these and other related questions and addressing each will benefit farmers and those who work on their behalf.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.