Biologicals
February 7, 1995
The term “biologicals” covers a range of products, from trace elements, to live cultures of microbes. If there is a common thread, it may be that these materials are intended to utilize natural processes and interrelationships in the agroecosystem. That is a goal of many farmers who are working to make their farms more sustainable. The question is: “Will biologicals help you get there?”
That is what this on-farm research is about. These were well-designed experiments carried out by farmers to see if biological products would pay off. Maybe someone was trying to sell them a particular item, or maybe they were following up on a biological because the promotional material sounded plausible to them. In some way, they probably all hoped these products would work. But they started with a test on a few acres. Often they asked the salesperson or company consultant how best to use the biological in the trial.
The results that appear here imply neither endorsement nor condemnation of any particular product. In most of the trials reported here, biologicals did not increase yields. However, producers are encouraged to carry out their own trials to find what works in their operations. PFI members have carried out close to 400 experiments on farms, and we have some good methods worked out if you are interested in doing your own testing. In reports of trials that involve proprietary products, we include brand names solely for purposes of information. The following explains how to interpret the table and describes the way these field trials were done.
Reading the Numbers, Knowing the Terms
Valid and reliable farmer-generated information is a cornerstone of Practical Farmers of Iowa. Consequently, PFI has worked to develop practical methods that safeguard the accuracy and credibility of that information. PFI members use methods that allow statistical analysis of their on-farm trials. Chief among these are: 1) “replication,” and 2) “randomization.” (See figure below, a typical PFI trial layout.) They have repeated, or “replicated,” the farming practices compared in a trial at least six times across the field. So trial results do not depend on a single comparison only, but on six or more. The order of the practices, or “treatments,” in each pair is chosen with a flip of the coin. This “randomization” is necessary to avoid unintentional bias. PFI on-farm trials have been recognized for their statistical reliability, which increases confidence in arriving at an unbiased conclusion. So, while PFI members don’t have all the answers, they do have a tool for working toward those answers.
When you see the outcome of a PFI trial, you also see a statistical indication of how seriously to take those results. The following information should help you to understand the reports of the trials. The symbol “*” shows that there was a “statistically significant” difference between treatments; that is, one that probably did not occur just by chance. We require ourselves to be 95% sure before we declare a significant difference. If, instead of a “*,” there is an “N.S.,” you know the difference was “not significant,” that is, the yields are not different.
Average statewide yearly prices for inputs were assumed in calculating the economics of these trials. For uniformity, average fixed and variable costs and time requirements were also used. These can vary greatly from farm to farm, of course. Labor was charged at $6.00 per hour until 1993, when $7.00 was charged. We costed labor at $8.00 per hour in 1994.
Dollar amounts shown in parentheses ( ) are negative numbers. A treatment “benefit” that is a negative number indicates a relative loss.
Researching Biologicals, Researching Systems
The farmers who carried out these trials have no way of knowing if the products were increasing the soil life or doing other things not visible to the naked eye. They were usually only measuring crop yield and, indirectly, profitability. Some people say you can’t test biologicals in strip plots because the “good bugs” swim across strips to wherever they are needed. The strips in these experiments were generally eight to sixteen rows wide. The reader will have to judge whether these were valid trials. 
Another criticism is that biologicals must be tested as part of a whole farming system. In some of these trials, farmers did maintain the experiment for several years, looking for cumulative effects. The systems question goes both ways. Systems with diverse crop rotations, manure, cover crops, and residue management are systems with plenty of native soil biological activity. The amount of additional microbes that can be added as a product is very small compared to what is already there. And added microbes face fierce competition from the native “bugs.” That could be why biologicals had little measurable effect on the farms reported here. On the other hand, if the farming system itself does not create the conditions that encourage soil biological activity, any added microbes will face a harsh environment in that soil, too. The best success with soil inoculants has been with symbiotic microbes - those that find a safe home in another organism. The common example is the Rhizobia bacteria added to the seed of soybeans, alfalfa, and other legumes.
Again, producers are encouraged to do their own testing to find out what works in their farming system. PFI has written a brief guide to setting up a replicated on-farm trial. For a copy of the guide, or to discuss trial results, contact: Rick Exner,
|
Year |
Cooperator/ Member |
Biological Product or Program |
Product Class or Purpose |
Biological Yield (bu/acre) |
Control Yield (bu/acre) |
Statistical Signifi-cance |
Biological Benefit $/acre |
Comments |
||
|
Corn |
Soybean |
Corn |
Soybean |
|||||||
|
1991 |
Leazer |
15-9-2-17S+ micronutrients |
101.8 |
102.2 |
N.S. |
($38.50) |
||||
|
1991 |
Mays |
15-9-2-17S+ micronutrients |
132.4 |
131.3 |
N.S. |
($38.50) |
||||
|
1991 |
Lubben |
ACA |
zinc acetate |
146.2 |
147.9 |
N.S. |
($4.56) |
Entire field received 60 lbs preplant N. |
||
|
1994 |
Lubben |
ACA |
zinc acetate |
62.7 |
62.8 |
N.S. |
($4.14) |
ACA applied with the herbicide. |
||
|
1993 |
Stonecypher |
Achieve® |
microbial seed treatment |
60.6 |
62.9 |
N.S. |
($10.00) |
Seed treatment applied with the starter fertilizer. |
||
|
1994 |
Stock |
Achieve® + Remedy® (Farm for Profit, Inc.) |
microbial nutrient and inoculant. |
159.5 |
160.5 |
N.S. |
($13.85) |
|||
|
1994 |
Stock |
Achieve® + Remedy® (Farm for Profit, Inc.) |
microbial nutrient and inoculant. |
54.0 |
53.0 |
N.S. |
($13.85) |
|||
|
1990 |
Leazer |
Ag Spectrum + Grozyme® |
108.6 |
116.6 |
* |
($46.86) |
A third treatment with 7-21-7 starter yielded 112.5 bu. |
|||
|
1990 |
Hermanson |
Agrienergy, Inc. |
biological fertilizers |
111.6 |
109.8 |
N.S. |
($26.35) |
Control treatment received conventional fertilizer (28% N). |
||
|
1991 |
Hermanson |
Agrienergy, Inc. |
biological fertilizers |
48.8 |
47.8 |
N.S. |
($18.67) |
|||
|
1992 |
Hermanson |
Agrienergy, Inc. |
biological fertilizers |
198.0 |
198.8 |
N.S. |
($34.88) |
Entire field received turkey compost, micronutrients, and starter. |
||
|
1991 |
Wurpts |
Agrienergy, Inc. |
biological fertilizers |
135.7 |
144.7 |
* |
($38.27) |
Poor weed control in Agrienergy strips. Excluded from average. |
||
|
1991 |
Wurpts |
Agrienergy, Inc. |
biological fertilizers |
31.7 |
31.3 |
N.S. |
($28.97) |
Control was ISU recommendation (no fertilizer). |
||
|
1992 |
Wurpts |
Agrienergy, Inc. |
biological fertilizers |
180.6 |
177.6 |
N.S. |
($34.89) |
Control was ISU recommendation (N fertilizer only). |
||
|
1992 |
Wurpts |
Agrienergy, Inc. |
biological fertilizers |
47.9 |
48.3 |
N.S. |
($41.69) |
Control was ISU recommendation (no fertilizer). |
||
|
1993 |
Wurpts |
Agrienergy, Inc. |
biological fertilizers |
101.3 |
100.4 |
N.S. |
($27.01) |
Control was ISU recommendation (N fertilizer only). |
||
|
1993 |
Wurpts |
Agrienergy, Inc. |
biological fertilizers |
30.9 |
31.1 |
N.S. |
($15.91) |
Control was ISU recommendation (no fertilizer). |
||
|
1994 |
Wurpts |
Agrienergy, Inc. |
biological fertilizers |
184.7 |
187.3 |
N.S. |
($10.11) |
Control was ISU recommendation (N, P, & K). |
||
|
1994 |
Wurpts |
Agrienergy, Inc. |
biological fertilizers |
60.6 |
60.3 |
N.S. |
($8.75) |
Control was ISU recommendation (no fertilizer). |
||
|
1986 |
Thompson |
AgriGrow |
121.1 |
116.1 |
* |
$7.11 |
||||
|
1986 |
Thompson |
AgriGrow |
138.4 |
137.2 |
N.S. |
($9.50) |
||||
|
1986 |
Thompson |
AgriGrow |
51.1 |
50.3 |
N.S. |
($6.50) |
||||
|
1986 |
Thompson |
AgriGrow |
46.0 |
46.6 |
N.S. |
($6.50) |
||||
|
1991 |
Carlson |
Arouse® |
microbial seed treatment |
93.5 |
91.2 |
N.S. |
($13.65) |
|||
|
1990 |
Reicherts |
Bio Soil, Inc. |
soil inoculant |
158.1 |
156.7 |
N.S. |
($25.58) |
|||
|
1991 |
Lubben |
Biomix® + Pepzyme® |
132.8 |
135.2 |
N.S. |
($10.00) |
1 lb Biomix, 6 oz. Pepzyme. Manufactured by Tainio Technique and Technology |
|||
|
1991 |
Lubben |
Biomix® + Pepzyme® |
51.7 |
50.0 |
* |
($1.81) |
1 lb Biomix, 8 oz. Pepzyme. Manufactured by Tainio Technique and Technology |
|||
|
1991 |
Leazer |
Bioroot Plus® |
root stimulant |
107.4 |
106.6 |
N.S. |
($14.40) |
Treatment with Counter yielded 114.2 bu. and netted $19.97 more than Bioroot. |
||
|
1992 |
Leazer |
Bioroot Plus® |
root stimulant |
140.6 |
137.4 |
N.S. |
($8.90) |
Treatment with Counter yielded 147.8 bu and netted $15.32 more than Bioroot. |
||
|
1991 |
Mays |
Bioroot Plus® |
root stimulant |
54.8 |
56.3 |
N.S. |
($7.20) |
|||
|
1989 |
Lubben |
Grozyme® |
151.4 |
149.9 |
N.S |
($8.00) |
12 oz./acre preplant incorporated. Both treatments received 28% N. |
|||
|
1990 |
Lubben |
Grozyme® |
53.5 |
53.2 |
N.S |
($8.00) |
12 oz./acre preplant incorporated. |
|||
|
1994 |
Olson |
Grozyme® + Agri-SC® (Ag Spectrum, Inc.) |
nutrient release, soil conditioner |
63.9 |
65.0 |
N.S. |
($10.76) |
Added to banded herbicide. |
||
|
1994 |
Olson |
Grozyme® + Agri-SC® (Ag Spectrum, Inc.) |
nutrient release, soil conditioner |
165.2 |
164.0 |
N.S. |
($10.76) |
Added to banded herbicide. |
||
|
1990 |
Carlson |
micronutrients |
131.8 |
130.5 |
N.S. |
($5.50) |
||||
|
1989 |
Carlson |
Molasses |
123.0 |
132.2 |
* |
($22.70) |
||||
|
1989 |
Lubben |
Molasses |
137.5 |
138.0 |
N.S. |
($1.60) |
3 gal./acre preplant incorporated. Both treatments received 28% N. |
|||
|
1990 |
Lubben |
Molasses |
53.5 |
53.9 |
N.S. |
($4.00) |
3 gal./acre preplant incorporated. Both treatments received 28% N. |
|||
|
1988 |
Broders |
P3K® (Petrik Labs., Inc) |
99.6 |
97.4 |
N.S. |
($18.00) |
||||
|
1988 |
Broders |
P3K® (Petrik Labs., Inc) |
79.6 |
82.6 |
N.S. |
($18.00) |
||||
|
1990 |
Lubben |
Trans-National AGronomy |
micronutrients and natural fertilizer |
157.6 |
166.2 |
* |
($56.04) |
TNA compared to farmer’s customary fertilizer |
||
|
1991 |
Lubben |
Trans-National AGronomy |
micronutrients and natural fertilizer |
47.6 |
50.9 |
* |
($30.92) |
starter and foliar |
||
|
1990 |
Bumgarner |
Triple Noctin-L® |
seed treatment |
39.0 |
44.2 |
* |
($13.95) |
hail damage |
||
|
* indicates a statistically significant yield difference (less than a 5% probability this great a difference would occur by chance). |
Average Corn: |
131.7 |
132.2 |
($19.27) |
Numbers in parentheses ($) show a negative benefit, or loss. |
|||||
|
Average Soybeans: |
49.9 |
50.3 |
($13.85) |
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