Talking Dirty with The Accidental Agronomist - Take One

The Homesteader Edition

After writing about agronomy for a year, I decided I would do something different.

Even though I have gained two more chins due to the number of prescription drugs I have been on for the past six months and my complete lack of technical skills, I decided I would start doing video interviews with all types of people either directly or indirectly involved in agriculture.

Nothing scripted or even really edited, just a one on one conversation about agronomy.

For the first interview, I sat down with a friend I’ve known for a while now to get her take on what agronomy means to her as a homesteader and let her ask a question or two as well.

Meet Diane, a backyard gardening homesteader from somewhere in Pennsylvania.

Ag 101 Week 51

Agronomic Testing Options

My titles have not become any more creative, but I get my point across.

This is the second to last post of the 52 Weeks of Agronomy Series. I would be lying if I didn’t say I’m slightly relieved. At the same time, I’m looking forward to having more time for other projects that do not require typing, or at least me doing it.  Maybe one will require me wearing out a red pen ripping apart someone else’s grammar. Who knows!?

What I do know is that we have come to the time of year farmers have questions. They have them year-round, now they have more time to ask them.

One of the most recent questions I’ve gotten is regarding the different types of agronomic testing available to farmers and growers.

The following is part of an email conversation with a grower I work within Maryland-

The farmer asked,

“I was thinking about doing a sap sample of the grass and clover in the field and also a Brix's reading at the same time. What are your thoughts?”

My response was,

“As far as the sap and Brix's testing, from an agronomic standpoint they won't change any soil fertility recommendations I would have. Everything I look at and take into consideration is based on soil tests in conjunction with tissue testing depending on the type of crop, farming system, and whether the grower will see an economic return for the costs of the tests. I'm looking at the actual nutrient levels of nitrogen, phosphorus, potassium, calcium, etc. There are so many variables like time of day the sample was taken, what part of the plant was sampled, and what calibration standards were used, it would make it difficult for an agronomist to base a soil fertility assessment on sap and Brix's levels. 

Tissue testing utilizes dry matter - it’s a picture at the moment at that part of the plant sampled as to what is there

Sap testing utilizes the fluid portion of the plant; it's similar to a blood test - keep in mind that fluids are constantly moving and every nutrient moves at different rates 

There are always variables in any kind of testing; you can't mitigate for everyone. However, soil and tissue testing are the best tools currently an agronomist has to look at what is going on at that moment in time.

That being said, and due to the fact, you are testing sugar and protein levels in the plant with the Brix's test, from a forage quality standpoint, the results may be of value to an animal nutritionist when determining rations and taking animal health into consideration.”

Here are some common agronomic tests, followed with a brief description and some of my thoughts on them.

Standard soil test- I talk in detail about what a soil test should include in week 24

Soil health assessments conducted by universities include soil typing and physical analysis of samples similar to what Cornell offers at the following link

In general, I recommend a standard soil test and use the link at the Web Soil Survey

Using both of those is comparable to Cornell’s package costing considerably less

 Soil paste test-

In general, this test shows what nutrients are immediately available to a plant because they are not bound to a colloid.

It is also one of the most accurate tests for measuring soil salinity which can be a common problem in soils in the central and western part of the country.

Some agronomist’s feel a standard soil test plus the paste test is the most accurate way to determine soil fertility needs. In my experience, it is farm, soil type, and management dependent as to whether you will see a return on investment for the extra cost.

 Plant tissue test-

As stated before in my email response; tissue testing utilizes dry matter - it’s a picture at the moment at that part of the plant sampled as to what is there.

It is a good measure of the nutrient status of a particular plant at that moment in time giving you a picture of what may typically be happening. It is a good indication of the efficacy of your fertility program as well. Tissue tests are dependent on timing, plant temperature, and growth stage the sample was taken.

Typically, guides are offered for the plant stage at which a tissue sample should be taken based on crop type. The sample is taken when the plant is actively growing, so timing is critical.

Spectrum Analysis offers a detailed guide to plant tissue testing

Plant sap analysis-

This is the best analogy I have come up with for sap testing-

Sap testing utilizes the fluid portion of the plant; it's similar to a blood test - keep in mind that fluids are constantly moving and every nutrient moves at different rates 

The following is an interesting article regarding sap analysis

I believe it can be a useful in-field test. However, there are variables such as operator error that would make me uncomfortable using it as the sole means of making fertility recommendations.

There are a few labs in the states that conduct sap analysis. One of them being

Brix test-

A brix test is the measure of the sugar content found in a plant tissue sample that has been pulverized, and the aqueous solution from that is then put in a refractometer and read.

Once again as with the sap testing, I believe it has in field use especially in a grazing operation. However, the variables associated with it make it suitable for field use and not what I would base a sound soil fertility program on.

I work with growers that use it in the field to help with harvest decisions with a tremendous amount of success. Using well-calibrated equipment with consistent protocols for testing has saved them time and money ensuring they harvest at that crop’s peak quality and nutrition levels.

Just as with plant sap analysis I believe it can be a useful in-field test. However, there are variables such as operator error and calibration protocols that would make me uncomfortable using it as the sole means of making fertility recommendations.

Soil Biological testing-

   Co2 Burst test-

This test is a soil health indicator, measuring the amount of microbial respiration.

The following pdf is the best explanation I have found

I would recommend growers use this in conjunction with soil nitrate tests to make a comparison and better calibrate any side-dress nitrogen applications that might need to be applied during the growing season.

The following is a well-written extension guide from Penn State explaining pre-side dress soil nitrate testing

  Microbial Identification-

Microbial identification is done with a microscope.

There are several consultants that provide soil microbiological identification services at the following link

 Water testing-

Water can be the carney in the coal mine especially when it comes to greenhouse management. pH is the most critical aspect of water testing in term of a soil fertility program and soil health. However, with water and its natural pH due to its source, comes with its dissolved elements that could be beneficial or not depending on the situation. The best measure to determine the impact irrigation water will have is through testing.

The following are links to labs I regularly use for soil and water testing

Entomological/ Pathological testing for field crops-

Before I started the 52 Weeks Series, I wrote a post titled “What’s an Agronomist, Anyway?”

Here’s an excerpt-

“On any given day as challenges and questions are posed to me, I have to think like a biologist, a chemist, a botanist, sometimes a pathologist, and if I’m really confident an entomologist. Usually, I defer to experts on the pathology and entomology. I know enough to be dangerous and kill stuff. “

As an agronomist, I kill stuff or keep it alive depending on what the farmer wants me to do.

What I can also say is I have been doing this long enough to make a definite diagnosis like thrips, aphids, blights, rusts, etc. However, when it goes beyond the obvious, I send a sample to the local land-grant university for identification. That’s what they are for, as well as other services.

Some good references to have on hand to make common identifications easier are-

Introduction to Plant Diseases: Identification and Management by George B. Lucas & Lee Campbell

Garden Insects of North America by Whitney Cranshaw

The Ortho Problem Solver by Michael D. Smith

 Forage test-

Ask an animal nutritionist or forage specialist. I can’t be an expert at all things.

In week 44 I discuss potassium and admit what my dad refers to me as

With that in mind here are basic ratios I look at when interpreting a soil test for forages-

Calcium to phosphorus 1.7:1

Calcium to magnesium 2.7:1

Calcium to sulfur 2.1-1

Potassium to calcium 1.5:1

Potassium to magnesium 4:1

Protein to sulfur 50:1

Nitrogen to sulfur 8.8:1

Potassium should be between 3.0-3.5% Calcium between 70-75% of the base saturation

One of the best agronomists who has an extensive forage background and one I’ve had the pleasure to be around and learn from is Dave Wilson from Penn State Extension.

Here’s a link to two articles he has written

In summary-

This is in no way an exhausted list. There are several tests that are similar but have different names based on the lab offering them.

I am not suggesting that every farm needs to be doing all the mentioned tests. Each one mentioned is another layer of management in the overall plan of how you are running your farm. They are not meant to be used in every case all of the time. Every farmer needs to weigh if the results from the analysis will yield an adequate return on investment for their operation.

Just as the title states, they are agronomic testing options.

Ag 101 Week 40

No Assembly Required

I posted this graphic on Instagram this week. At the time, I had planned on writing a lengthy explanation as to what I meant and at the last minute deleted. I wanted to see what kind of response I would get.


One person asked if I was against soil building techniques. The following was my reply

“Not against good management practices at all. They are part of what it takes to be good stewards of the soil. But, soil comes pre-assembled. It’s like a set of shelves that are ready and waiting for you to start stacking books on. Or better yet, to start using and storing nutrients in for the microbes and plants that rely on it. All you need to do is take time to understand the specs the shelves came with, or what I refer to as the inherent characteristics your soil came with. We amend, which is a temporary change to the physical and chemical characteristics and we fertilize which is strategic and is intended to feed the biology in the soil and the plant, depending on the type of inputs you use. Neither build, they complement what’s already there.”

Another person explained, “permaculture allows for amendment added in 1-foot layers starting from a depth of 6 feet below grade. That’s building soil…The amendments are specific and by their nature create a mycillium layer right at the frost line. “

To this, I responded

“If I understand correctly, you still have the parent material left. For lack of better terms, that is what ‘builds soil’ and dictates its characteristics. I have long wanted to understand permaculture better and have not taken the time to do more research on it. If you have any good resources I would love to read more about it.”

If indeed taking away the top six feet is what permaculture prescribes, it seems pretty destructive to me. Here again, I don’t know that much about it.

Three things I want to point out-

1.     Soil doesn’t know and or understand any of this. It comes the way it is and has had stuff growing in it way before we got here. We need to either work with or against it. It is selfish and doesn’t follow trends.

2.     If people understood the difference between amending and fertilizing that alone would save them money and have a more significant impact on helping the environment than some of the other things we do.

3.     Long-term soil fertility, the kind that keeps soil healthy and you and the next generation farming and eating is a balance between the actual make of the soil specifically the clay fraction, organic matter management, and the physical management of it as well.

The notion that we build soil has been around for a while now. You see it phrased that way on social media, industry gurus say it all the time, everyone who’s anyone has used the term at some point in time. It sounds powerful and gives us a sense we are in control. It is what good marketing is made of. It’s even on one of my favorite books, Building Soil for Better Crops by Magdoff & Van Es. If you’re in the industry, you want to jump on the bandwagon and ride the wave of being known as the one who builds the best soil ever! Right?

Here’s the challenge I have with the statement, “build soil”-

We can’t build soil. It comes no assembly required. You don’t open a box like you do from Ikea and put the pieces together.

It comes pre-assembled with both physical and chemical characteristics that we can’t change. They are dictated by its parent material. We have nothing to do with it. The soil is what it is, and we have to except that.

I talk about those in weeks 8 & 9

However, there is one thing we can do. We can amend it. But, there’s another kick in the pants. No matter what amending you do, no matter what type of amendments you use it is only temporary. It doesn’t last forever. Soils main objective is to go back to what it originally was no matter what we try to do with it. You always have to be tinkering with it to keep it the way you want it.

I hate to say it, but there is no Ronco Set It & Forget It when it comes to soil. It is a constant work in progress.

I have said that organic matter gets all the attention and clay is often overlooked while being misunderstood for what it brings to the table in soil management.

If I were to put it into somewhat crude and simple terms

Organic matter

is the girl you want to date. She’s fun, easy to get along with, doesn’t require much attention and is relatively inexpensive. It is the most biologically active fraction of the soil. It does have a negative charge due to humus. However, it is referred to as being loose because it doesn’t have the structure that clay does. Humus, all though being somewhat stable breakdowns faster than clay and needs to be replenished to keep nutrient holding capacity and availability in check.


is the women you want to marry. However, she requires more strategy. She won’t go for just dinner and a movie. She might need something more expensive to keep her happy. However, if managed properly and the timing and application are well thought out and strategic, it will be well worth the effort and expense.

When you have a balance of both organic matter and clay you get married and live happily ever after. I realize my analogy is probably offensive to some, but it illustrates my point.

All of this leads back to knowing your soil type, getting a soil test and balancing the biological, the chemical, and the physical.

Ag 101 Week 24

Six Things Every Soil Test Should Include


Last week I wrote about four things your agronomist should know about you. One critical piece of information when working with an agronomist is having a soil test. It is the starting point for them to be able to build a fertility plan that makes financial and environmental sense for you and your farming system.

One challenge I face when working with farmers is not that they haven’t gotten a soil test done. However, that the results are missing critical pieces of information that are needed to make the best recommendations tailored to their specific situation. Soil test results are a snapshot of what was happening then when it was collected, however, without the entire picture making the best fertility choices can cost you financially and have unforeseen environmental impacts both on and off your farm. Investing a few minutes and dollars can ensure you get all the necessary information that will save you in the long run.


1.     pH

pH is the potential amount or concentration of hydrogen ions in the soil. It is represented by a negative logarithmic scale, zero through 14. Acidic soils, represented by a pH of below 7.0, have a higher concentration of hydrogen ions available. Alkaline soils, represented by a pH above 7.0, have a lower concentration of hydrogen ions available. It is how many hydrogen ions are in that particular soil. – Talk to the Blueberries

pH is the foundation for all soil chemistry. In which it plays a role in microbial activity that drives nutrient reactions in the soil directly affecting plant health and yields.

2.     Organic Matter (OM)

Often, I refer OM to being the pantry that microbes have access to, where nutrients are stored that plants need. Due to the fact this fraction of the soil acts as a holding area, or pantry, for several nutrients it is important to know what percentage makes up the soil in a given sample. 

OM plays a role in storing a vital nutrient, such as nitrogen. The estimated amount of nitrogen (lbs./ac) that can be released or ENR that can potentially be available over the growing season is relative to the percentage of OM present in a soil. Decomposition of organic matter can release about 20 lb. N/acre/year for each percent of organic matter. Knowing these amounts can help to adjust nitrogen inputs over the course of the growing season leading to better cover crop choices, more effective crop rotations, and increase the efficiency of a fertility program.

Depending on the lab this may not be included in a standard package and can often be overlooked. Pay close attention to the soil sample submittal form, making sure it is tested for each sample.

3.     Cation Exchange Capacity

If OM is the pantry where the nutrients can be stored, cation exchange capacity or CEC is the number of shelves or sites you have to store nutrients such as calcium, magnesium, potassium, and other positively charged ions.

Say, for example; I have two pantries’ in our home one with eight shelves and a smaller pantry with two shelves. That gives me a total of ten shelves to place food on for storage. Clay, which is predominantly negatively charged could potentially be the pantry with eight shelves and be able to store nutrients that have a positive charge. OM could be the pantry with two shelves, being made up of both negatively and positively charged ions, can store either. In the case of nutrient storage in soil, how much and where is relative to the amount of clay and OM and the sum is referred to as the Total Cation Exchange Capacity (TCEC).

4.     Base Saturation

Base Saturation is a percentage of a nutrient, or cation makes up the TCEC. How much shelf space in the pantry that particular cation is occupying in relationship to the total size of the pantry.  When it comes to balancing soil nutrients, there is a school of thought that uses percent base saturation results. Whether that is the measure you are using to adjust nutrients or not, it is still a good overview as to the ratios nutrients are present in the soil. And can be used to help determine the most useful input to achieve the desired balance of nutrients based on other factors as well.

Nutrients that should be included are

Potassium (K), Calcium (Ca), Magnesium (Mg), Hydrogen (H), and Sodium (Na)

5.     Macro Nutrients

For this post, which is to make sure farmers get the appropriate tests results for an agronomist to make sound and appropriate recommendations, I am listing nutrients that a standard soil test should include, and as they are categorized by most labs across the country. For example, I could go into more detail talking at length regarding Nitrate testing and the categorization of sulfur being a micronutrient as opposed to a macro. But that’s not the point of this post.  What a farmer needs to have reported in the results are the following essential nutrients that make up the majority of a plants diet including-

Calcium, Magnesium, Potassium, and Phosphorus

6.     Micro Nutrients

Sometimes referred to as trace elements, due to the fact they are required in smaller amounts than the previously listed macronutrients.

These should include sulfur, zinc, boron, copper, manganese, and iron. Depending on the lab, sodium could be reported under this category as well. I’ve listed them in importance for how and why I make fertility recommendations. Farmers need to note that some labs charge per element or as a group. You have to be diligent when filling out the soil sample submittal form, including ones that are pertinent to your situation.

Don’t let a few extra minutes or a couple of extra dollars keep you from getting-

The Six Things Every Soil Test Should Include