Monitoring | Where To From Here?

Part 3 | Ray Archuleta Series

Cover photo

March 12 & 13, 2024 – Bibulman-Wadandi Noongar Boodja

“As the eyes are the window to the soul, the shovel is the window to the soul of the soil”

For the final session Ray introduced the topic of tools. Annuals are tools. They are one of the many tools we can use to heal soil. According to Ray nothing heals soils as quickly as annuals do, though they are expensive. Incorporating them with biology is a powerful mix though always together, never one without the other.

Soil contains five spheres

There are five spheres or zones found in soil, namely:

  1. The rhizosphere – the zone around plant roots inhabited by microbial populations
  2. The porosphere – the total pore space e.g., the spaces within and between aggregates
  3. The aggregatusphere – the soil aggregates – soil minerals bound with organic materials
  4. The drilosphere – the part of soil influenced by earthworm secretions, burrowing and castings
  5. The detritusphere – zone of litter decomposition and ‘hot spot’ of microbial activity

Each sphere plays a unique and essential role in soil. Healthy, functional soil has all five spheres. Without the spheres, soil is just mineralogy.

Ray mentioned a sixth sphere that is separate from soil – the phyllosphere – the entire above-ground surface of a plant e.g., leaves, that serves as a habitat for microbes. Ray discovered the phyllosphere from a dairy farmer who couldn’t sell his milk (raw and unpasteurised). Rather than waste it, he put in his tank, added water, and sprayed it over his wheat crop and increased his yield by 10 bushels/acre (Bu/Ac). The phyllosphere is one reason biological stimulants work because they interact with and feed microbes that live on the surface of leaves.

The place to start with soil in your context is with a shovel. Dig and look for the presence of each sphere. Only by looking at soil can we see what’s going on. We need to look and monitor.

“All soil tests are wrong, some are useful” – Buz Kloot, Ph.D.

All computer models, for example on soil erosion, are wrong, some are useful. Our world is elegant and complex. No model can possibly predict how the planet works in its entirety. Similarly, no one soil test will tell us all we need to know.

50% of all biodiversity lives in the soil.

Therefore, wanting to know or predict what happens in soil is just not realistic. However, what we want to know is can we get a snapshot from a moment in time with some good information to help us make a good decision?

Soil and soil tests are complex. This was highlighted with research by Dr Brad Joern who studied soil test irregularities across the US and the consequent use of fertilisers. The results were all over the place and ‘magically’ changed simply crossing from one side of a state border to the other. Ray noted in the US that whenever the crop value goes up the cost / use of fertiliser goes up too.

Fertilisers do not feed the plant. Fertilisers feed the microbes and they feed the plant

From the 1930s – 2000s we’ve known only about 40% of nitrogen fertiliser reaches the plant. The other 60% is either leached or feeds the soil mafia, the microbes. Ray stressed “fertilisers do not feed the plant. Fertilisers feed the microbes and they feed the plant.”

Ray shared some typical nitrogen yield response curves for corn grown in the US. What is often missed or ignored by most people is that zero fertiliser yielded almost 100% of the response when fertiliser was applied. Importantly, Ray emphasised that if the curve does not have a zero control, i.e., a point where no fertiliser was added, the curve is meaningless and tells us nothing,

Only 1 to 2% of farmers regularly (i.e., every 2-3 years) calibrate their yield response to 0%, 50% and 100% of full rate of fertiliser application. Most farmers don’t do this as a practice. Ray says, “If you don’t calibrate you must like writing cheques and wasting money.” He emphasised this practice is important because we need to calibrate fertilisers for our own soils. Don’t wait for someone else to do it for you. As Ray concluded “do the test yourself, be the farmer scientist.”

Ray introduced Rick Haney who worked on a farm until age 40. He then went to study science and work for the USDA at the Agricultural Research Service. Rick studied fertiliser use and corn yield. The research from 170 different test plots across Illinois showed some plots with zero units of fertiliser applied resulted in corn yields of 160 Bu / Ac. However, other plots with 300 units of applied fertiliser similarly produced 160 Bu/Ac. The conclusion: “fertiliser has been wasted. It’s expensive and we’ve been wasting it everywhere.” The bottom line: if we don’t calibrate, we don’t know. Interestingly, Ray shared that the more fertiliser we use the more its efficacy decreases. The natural system doesn’t like fertilisers and consequently as we use more, the more we waste.

Fertiliser usage is based on the Mineral Theory of plant growth which Ray shared, “is flawed science that’s based on the wrong premise. It’s flawed because it doesn’t involve biology. This is the reason we see soils as they are, everywhere, conventionally farmed, bared off for half the year.”

Don’t be enamoured with the tool, it is just a tool

It’s important to remember that fertiliser, like annuals, is just a tool. “There are many tools. The person who understands the principles is free to choose the methodology, the tool. Once you understand this, you’re all set.”

The Haney Soil Test measures what’s ACTIVE in the soil, not what’s in the soil

Ray introduced the Haney Soil Test. It’s very different to conventional soil tests. Both are useful as they give different information. In simple terms the Haney test measures what’s ‘active in the soil’ as opposed to ‘what’s in the soil’ as conventional tests do.

As detailed below, the Haney test gives us three key measurements to assess soil health:

  1. Water soluble carbon
  2. Water soluble nitrogen
  3. Soil respiration

Note, the Haney test is used in Ecological Outcomes Verification (EOV). EOV uses a comprehensive set of criteria to independently assess landscape function. EOV monitoring was featured in the 2023 film ‘Rachel’s Farm’ by Rachel Ward.

Conventional soil tests re-wet soil samples using strong laboratory acids. These acids extract all the molecules in the sample and then they’re analysed. This method ‘forces’ the minerals out of the ion exchange sites in the soil. In other words, the acid ‘forces’ the minerals, the information, out of the samples to inform us what’s in the soil.

In contrast, the Haney test uses biomimicry and green chemistry. Rick Haney came up with the novel idea. Rain is water. Therefore, instead of laboratory acids, he used water as the major solvent to extract the molecules from soil to mimic what happens in nature. Haney also recognised that plant roots exude mild organic acids to solubilise soil nutrients. Therefore, to mimic the actions of roots the Haney test also uses several mild organic acids (e.g., malic, oxalic, citric acid) as solutes to extract molecules from soil. Note, other root organic acids include malonic, acetic, fumaric, succinic, lactic and tartaric acid.

Rather than force minerals out of rock for analysis like conventional tests do, the Haney test is natural and importantly, more meaningful. Samples are re-wet with water or mild organic acid before undergoing sophisticated water analysis. The Haney test measures the molecules that water makes available to the plant, and it measures what the plant makes available via their root exudates. At the end of the day, we want to know what is soluble in water and what the plant makes soluble. In other words, the Haney test informs us what’s active in the soil.

It’s not the amount of organic matter in soil but rather the quality of soil carbon that matters

According to Ray soil organic matter (SOM) is not a good comparison for soil, it’s too general. SOM is the excretions and secretions of life and death. Everything is eaten, secreted or excreted – carbon molecules, aggregates, super-biotic glues, they’re all there. SOM is way more elegant than we think.

It’s the quality of the carbon in the soil that matters. To illustrate this Ray shared that the SOM gives us an idea of the size of the house but tells us nothing about what’s in the refrigerator. If we ate the same poor-quality food, like hot dogs, every day life’s going to be tough. We might have a big house but no food. It’s the quality of food in the refrigerator that really counts. This is what the Haney test provides. Ray shared he’s seen soils with 30% carbon and the plants are all dead because there’s no quality food present / available.

Note, the conversion rate: 1% SOM = 6,000 ppm (parts per million) carbon.

SOM is only part of the story. It’s only one indicator. From Leviticus 11 “the life is in the blood.” The blood of the soil is the soil water. It’s the aqueous solution with all those carbonaceous molecules and microbes swimming around.

A blood test taken by a doctor is a passive test that says a lot about our health and how well our various bodily systems are working. Similarly, the Haney test is also a passive test, yet it tells us a lot about the health about our soil. It is what it is.

The Haney Test measures organic nitrogen that is missed in conventional soil tests

Conventional soil tests measure inorganic nitrogen (N) and molecules like nitrate (N03-). Importantly, the Haney test goes further to also measure organic nitrogen which is any carbon molecule with a nitrogen bound to it. Importantly, all organic (carbon) compounds are detected with the Haney test. Conventional tests miss the organic nitrogen which is crucial as it can be 50% of total nitrogen. Farmers have literally wasted thousands upon thousands of dollars applying nitrogen fertilisers that they didn’t need because they didn’t know about their organic nitrogen. With the Haney test we can now measure it and consequently save farmers money on fertilisers.

Ray shared a great video (similar videos can be found on YouTube) to remind us that plant / tree biomass comes from the air not the soil. Plants make their own food via photosynthesis and sunlight to convert CO2 from the air into sugar. Plants combine sugar molecules into long molecules like cellulose which is used to build plant structures such as cell walls. As cells grow, they divide and make new cells. It’s the new cells that make the plant get bigger. From seedling to tall tree, plants grow by pulling carbon out of the air. From 95 – 98% of tree biomass comes from the air: C, H, O, N.

Regenerative agriculture is often wrongly criticised because it ‘mines the soil’ for nutrients and does not put back (with fertilisers) what it removes, when in fact most of what plants use comes from the air. The reason most soil tests are measured in ppm is because 1) they are in low amounts and 2) very little that a plant needs comes from the soil. Plant nitrogen comes from organic molecules and predation (e.g., rhizophagy and microbes eating microbes). However, solubility or rather availability is the real issue. For instance, most soils have lots of phosphorus (P) and potassium (K) but it’s not readily available to plants. This is where the biology comes into fold.

Plants are carnivores and eat bacteria to absorb nutrients by rhizophagy

Distinction: N, NH3, NO3 are forms of inorganic nitrogen. Organic nitrogen is any carbon molecule that contains N. Plants can take up both inorganic and organic forms of nitrogen. Plants are also carnivores – plants eat bacteria in a process known as rhizophagy (see pioneering work by Prof James White at Rutgers University). Plants take up bacteria and strip them of their outer wall and use them for food. Ray joked that “vegetarians eat carnivores.”

The take home message is that conventional tests measure inorganic nitrogen while the Haney test measures both inorganic and organic nitrogen. We add these numbers together to determine more accurately the total amount of nitrogen in soil. It is worth noting that plants also love inorganic nitrogen. They exude lots of carbon molecules (e.g., sugars) that wake up and feed the biology to mineralise nitrogen and make it available to plants. The Haney test also measures water soluble organic carbon. Using Ray’s earlier analogy, the Haney test tells us what’s in the refrigerator.

The Haney Test accurately assesses soil health

The final part of the Haney test is soil respiration that measures the activity in soil. The higher the activity the more work we can get out of the microbes. Combined with the water-soluble carbon and nitrogen results from the Haney test we get an accurate assessment of soil health.

The Haney test has huge implications for farmers. It helps them save money on fertilizers because it shows exactly what their soil needs. Before, they might have been buying too much fertilizer without knowing what their soil really required. Now, with this test, they can assess everything properly and use only what’s necessary, cutting costs and improving efficiency. The Haney test was invented to give farmers the confidence they need that they have carbon and nitrogen in their soil to get them to reduce fertiliser use.

A few technical points about the Haney test. For sampling, the temperature needs to be between 13° – 30°C. Ideally, collect 50 – 70 core samples per hectare. The more samples the more accurate the result. Take samples between 0 to 20 cm deep. 80% of all fertility and nutrient recycling occurs at this depth in this root mass / zone. The first time you perform the test Ray recommends also taking samples from between 20 to 40 cm deep to see what’s going on deeper in the soil Mix the core samples together and place into a Ziploc bag. This becomes one sample for analysis.

To conclude, Ray also suggested doing the total dissolved nutrient test. This test tells us what’s embedded in the rock. It tells us how much is stored in the rock that plants can’t access now but might be able to in the future. “It’s good to know what is and isn’t stored in the rocks.”