A message from Clint Frese and Luke Holst, owners of Bio Ag management.

When Luke and I first started working together in 2006, our focus was to use on-farm research and data management to make sound agronomic decisions at the field level. We have learned a tremendous amount from our failures and successes over the past 15 years. In 2016 we started Bio Ag Management with the main goal of producing and implementing biological programs. It has grown to much more than that today. To shed better light as to how we got where we are now, I need to start from the beginning.

I’ve been down two very different roads in agriculture. One road followed a traditional, conventional approach to fertility management: removal rates plus build up on P and K fertility. Single pass nitrogen programs in the fall, with the addition of starter fertilizer at planting and a fungicide pass in R stages. My only focus on in-season fertility was in a year when precipitation was above average and I would add more nitrogen if my nitrogen budget wasn’t already spent. A deep tillage system was used across the board, and soil testing was only used to monitor ph, and try to use broadcast fertilizers to make my P and K numbers reach the magic 60 lb. P test and 300 lb. K test. While this system was profitable, it was very labor and capital intensive. In dry years, I was spending too much on inputs for crop output. In years with above average rainfall, I suffered from nutrient loss from front loading my entire crop’s fertility needs 9 months before peak corn and soybean nutrient demands. I found that this system works best in a normal year when Mother Nature didn’t throw us too big of a curve ball either way.

The other road was very unconventional: a biological systems approach to row crop farming. It was based on principles that soil microbiology controls the biggest part of delivering nutrition to our crops, and that our soils are loaded with all the nutrients our crops need. In this system we cut P and K applications altogether. We Lowered our applied nitrogen to .5 to .6 lbs. of N per bushel, and reduced/eliminated fungicide/insecticide applications. Tillage was reduced to minimum till/strip till. Instead of starter fertilizer, we ran our Bio Ag E biological program in furrow to jumpstart the plant/soil biological relationship. And while this system was profitable as well, it had holes in it. Some of the challenges began to show in the above-average precipitation years. Beneficial soil microbes don’t thrive underwater. Different soils release and hold plant-available nutrition differently under varying temperature and moisture levels. Fields that are not tiled or poorly drained fields were showing compaction issues from excessive rainfall and planting/ harvesting in wet conditions. A biological system shines brightest in average to slightly drier than normal precipitation years, due to very few input dollars being spent on the crop and our biological program’s ability to increase plant’s root systems for better water and nutrient uptake.

This leads us up to where we are today: a hybrid system, one that focuses on soil health and proactive biological programs to start our crops off with balanced nutrition and a more robust root system. We couple that with in-season soil and plant tissue testing to better understand the strengths and weaknesses of our fertility management decisions. We have become proponents of in-season application of nutrients to be reactive with our growing season and plant nutrition demands. Our research has been focused on developing a better understanding of how the right biological programs affect our fertility management decisions. In this newsletter we hope to share with you our thoughts on where the data is trending.

Biological Programs

  • Bio Ag Management is currently testing over 10 biological programs locally in replicated plots to make sure we are producing the best biological programs for our area. This will be expanded to be a nationwide research project next year.
  • A good biological product should always be used with bio-stimulants (microbial food sources).
  • Biological products have been shown to be synergistic with bio-stimulants, PGR’s (plant growth regulators), and Silica.
  • Bio Ag management’s Bio Ag E program and Biovante’s Root Exudate Program have been top performers.
  • Good biological programs should affect more than just nitrogen (see charts below).
  • We usually tend to pick up increased nutrition from our biological programs as early as V5 in plant tissue tests, and that has been a great indicator of yield increases to come at harvest.
  • Our biological programs tend to aid in nutrient balance early in a plants life cycle resulting in a more robust root system and greater plant biomass.
  • We have found that biological programs are, most of the time, a better investment than starter fertilizer.
  • Higher plant nutrition levels early in vegetative growth stages are great but come with a responsibility to make sure we keep those bigger, healthy plants fed later on in the growing season. In-season soil and tissue sampling are critical for evaluating biological programs as well as for finding fertility efficiencies and deficiencies when using biological systems to trim fertility budgets.

Yield data Plot 1

Yield data from Bio Ag Management plot evaluating 4 different biological-based programs

Yield data Plot 2

Data from a second plot replication evaluating 4 different biological programs

Left untreated right treated.

Plants taken from treated and untreated areas using BioAg E in furrow program. Left untreated right treated.

Bio Ag Management Bio Ag E in furrow program

Bio Ag Management Bio Ag E in furrow program

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Biovante Root Exudate Program


Root Exudate graph

Graph shows nutrient levels increased when Root Exudate program was applied.


Over-applying nitrogen is harder on our soils than tillage due to its negative effects on soil carbon. Carbon is used in the soil every time nitrogen or other nutrient conversions take place. Soil carbon is the life blood of our soils. If you think about it, soil carbon is the reason some ground sells for $5,000 an acre and some sells for $15,000 an acre. Protecting and building soil carbon, we feel, should be a high priority.

  • Nitrogen as a nutrient has a synergistic relationship with sulfur, molybdenum and sugar.
  • Sulfur and Nitrogen are essential building blocks of protein. A proper balance of Sulfur and Nitrogen greatly increases the efficiency of this process.
  • The proper Nitrogen to potassium ratio allows for better late season grain fill and plant health.
  • Tissue testing has shown to be a very accurate guide in evaluating the balance of the nitrogen and potassium and nitrogen and sulfur ratios.
  • Our biological programs have shown to increase nitrogen levels in the plant from 10% to 30%.
  •  A .5 to .7 lbs of N to bushel of corn is very attainable when utilizing biological programs and a 2 pass N program.
no in-season applied

No in-season nutrients applied.

In-season nutrients applied

In-season fertility applied

Sample ears

Sample ears pulled from above trial.

Plant Nitrogen Levels Bio Ag E and Root Exudate Program

Plant Nitrogen One graph

Plant Nitrogen levels at V4 and V8 from 2021 Bio Ag Management plot. Check vs. Bio Ag E in furrow program and Biovante Root Exudate program.

Plant Nitrogen Levels Bio Ag E and Root Exudate Program

Plant Nitrogen Graph 2

Plant Nitrogen levels at V4 and V8 from a second 2021 Bio Ag Management plot. Check vs. Bio Ag E in-furrow program and Biovante Root Exudate program.


  • A good biological product can easily increase Phosphorus levels in the plant. We have observed gains in tissue test levels from 12% to 40%.
  • Soil test levels can double, even triple, in Phosphorus from fall to in-season samples IE: a 20 lb. fall P test can be a 60 lb. P test in June.
  • We see very little difference in tissue test levels of P to the plant when comparing fields with dry fertilizer applications of P to fields using biological products like Bio Ag E or Biovante’s Root Exudates’ program.
  • Biological programs can be much more cost effective and do more for nutrient delivery than dap or map applications.
  • In general, West Central IL soils have a high P saturation (plant available P)
  • Our data set shows that in most cases, regardless of fall Phosphorus test levels, Phosphorus is the first nutrient to cut out of your fertility plan and monitor.
  • High levels of phosphorous can limit zinc and, to a lesser degree, calcium.
  • Never apply lime and then apply Phosphorous without tillage or time and rainfall between applications. Calcium and Phosphorus combine to form Calcium Phosphate.

Leaf Test P Values by Growth State


average P leaf test levels by growth stage over approximately 200 samples that have had P fertilizer rates applied ranging from 0-200 lbs.

Plant Phosphorus Levels Bio Ag E and Root Exudate Program


V4 and V8 leaf test Phosphorus levels from 2021 Bio Ag Management plots. Checks vs. Bio Ag E in furrow program and Biovante Root Exudate Program


  • Potassium fixation (tie up): Potassium getting bound to clay particles is a big problem in West Central IL.
  • Tissue test data shows that from V7-R growth stages, it is a struggle to maintain optimal K levels, even when K has been applied.
  • If a soil test Hydrogen base saturation falls to 0, it is a good that pre plant or in season K applications will have a yield response.
  • In our 2021 data set the highest late season K tissue tests have been from banded (strip-till) applications, with rates ranging from 60-120 lbs. per acre of potash combined with an in season Y-drop application of K.
  • Large rates of potash spread in the fall (500 lbs. plus) raise K levels higher in the early growth but are not maintained throughout the season.
  • Replacing a 2 year spread program (K spread every other year) with a yearly application tends to show higher tissue test levels in corn and soybeans.
  • In-season applications of Potassium with Nitrogen and Sulfur shown more consistent yield gains than applying Nitrogen alone.
  • Dry Humic Acid applied with dry fertilizer has shown to increase K in plant tissue by as much as 25%. Calcium levels tend to come up as well.
  • Fixing compaction and using farming practices that promote good soil structure will aid in potassium uptake.
  • SiO2 (silica) is synergistic with potassium. Adding a silica-based product like Incite by Biovante (a silica/ potassium product) has shown great results in aiding in plant health and ultimately yield.
  • High nitrogen loads can limit potassium uptake. The N to K relationship is very important for plant growth as well as plant health.
  • Tissue testing has shown to be an accurate way of evaluating one’s potassium program.

Leaf Test K Values by Growth Stage


Average leaf test K levels from Bio Ag Managements 2020 leaf test database.


Average leaf test K levels from Bio Ag Managements 2021 leaf test database.

Fall Strip Till vs. Spring Broadcast Potash

Potash graph

Leaf test K levels from approximately 20 fields. 10 with banded strip Potassium fertilizer at a low rate (60lbs per acre of Potash) and 10 fields with 100lbs of Potash applied through a spinner spreader.

Y-Drop/In-Season Fertility

  • Best results with y-drop come from using tissue test data to make the right decisions on what to put in a y drop mix or if we apply at all.
  • It is best to test every field in the V5-V8 window in corn. We will then analyze tissue data to figure out where we can offer the most support on a field-by-field basis ranking fields with highest probability of a positive ROI.
  • If you plan to do a 2 pass system, cutting your nitrogen and potassium pre-plant rate is a good idea.
  • Humic Acid has been a great ride along with Y drop or dry fertilizer. It helps chelate applied fertilizer (keeps fertilizer from reacting with other nutrients and soil/clay particles). It is also a urease inhibitor and stabilizes NH3, UAN, and urea fertilizers.
  • Dry or liquid humic acid is great to use on soybeans after soybeans, as soybeans are a carbon negative plant (use more carbon from soil than they put back).

We feel the next tier in higher yields will come from using soil health practices and products to keep soil moisture and temperature as constant as possible and to learn how to better feed our crop later in the season.


  • Boron is a nutrient that is generally always low and across our tissue data set. The best timing window for application is 1 week before flower/ tassel through the R stage.; Boron can be applied through Y-drop or sprayed foliar.
  • Zinc is a nutrient that shows up low in tissue tests in high phosphorus soils early as well as ahead of tassel. BioCore Zn as a seedbox treatment works well early. Zinc with fungicide has shown good results in corn.
  • Manganese is a nutrient that shows deficiencies mid-season and is a great ride along with second pass chemicals. Mn is a highly effective foliar, and timing is best right ahead of flowering.

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