The land is cursed. It gives thorns and thistles. Nothing grows, just weeds, pioneer plants that survive in dry-cracked, poorly aerated, compacted, and depleted soil. Any other cash crop plants, plants that we eat, are weak, tiny, and with lots of pests and diseases, many of them did not get to the maturity stage or reach the full potential that they were made for. The yield is minimal and an effort with such soil gives hard work, bent spine, constant weeding, repeated watering-crusting cultivation cycle, heavy protection against pests, fungi or bacteria diseases, and lots of other interventions. Why is it so?
In healthy, rich, productive soil you will see fewer pioneering weeds, but more diverse plants, fewer pests, but more diverse insects, the soil is soft and not very often cultivated, plants hold natural immunity, the yield is gorgeous and your smile on your face shows your joy from peaceful gardening labor. The healthy soil gives life and health, life and health to plants, life and health to the soil food web (everything below the surface), and of course, life and health to all living creatures above, including us humans. The healthy soil gives plants that are packed with all required essential nutrients: saccharides, proteins, fats, vitamins and minerals, antibiotics, probiotics, prebiotics, and much more. All is in the right balanced way pointing to our smart and loving Creator.
Having a proper amount of water and air, a healthy plant requires three legs that depend on each other – good photosynthesis, available balanced minerals, and flourishing biology in the soil (Figure 1). For good photosynthesis in plants, balanced minerals in an available form are needed. Plants feed the biology in the soil with abounded products of photosynthesis. And, without biology, unavailable minerals in the soil are not transformed into a form available for plants. It is a cycle that is often broken, resulting in an unhealthy garden/farm. How to turn on the cycle? By knowing the principles, one can help to run the cycle properly. We can become guardians of the soils. The solution dwells in balanced available minerals in the soil, and practices that enhance photosynthesis and soil biology.
Figure 1. The healthy plant requirement cycle
Today, I would like to focus on one leg only – the minerals in the soil. The presence of essential minerals in available form is required in the soil, but this is not the whole truth. The optimal concentration of minerals with respect to the capacity of the soil is also very important. Temperance is the health law that applies to plants too. More doesn’t mean better. Deficiency or excess of each mineral affects the quality of growth in various ways.
For example, calcium (Ca) is an essential mineral for plants. Bioavailable calcium is a constituent of plant cell walls and has a function in cell division, cell elongation, cell structure, root development, and nitrogen absorption. Ca is essential in the photosynthesis process and has many other functions. A typical deficiency symptom is blossom end rot (Figure 2)
Figure 2. Blossom end rot of tomatoes, dying main bud, and cork spots of apples as Calcium deficiency symptoms.
Other deficiency symptoms of Ca are bending of young leaves and dying of the main bud. Cork spots and bitter pits also reveal an insufficient amount of calcium in apples. On the other hand, the excess of calcium in the soil limits the availability of other cations such as Mg, and K, and symptoms are typical for deficiencies of Mg and K, respectively. We can go through all essential elements, one by one and describe the function and deficiency and excess symptoms. We could see that elements are not only related to plant well-being, but also to weed pressure, soil structure, capacity to hold water, etc. One can find such information on the web (for example here: en.wikipedia.org/wiki/Plant_nutrition) or in any good agricultural textbook (see examples in references below).
What is the right concentration of minerals? The roots of the knowledge were established decades ago by Dr. William Albrecht, chairman of the Department of Soils at the University of Missouri. By observing soil quality and food quality he proposed direct relation between bad quality of forage crops and livestock health. He concluded that cations in the soil have the ideal balance when having 10% of H, 69% of Ca (in the range between 60 – 75%), 12% of Mg, (ranging from 10 to 20%), 2 to 5% of K, 0.5 to 5.0% of Na and 5% of other cations (en.wikipedia.org/wiki/William_Albrecht). The ideal ratio works independently in almost any common soil type. The sandy soil with a low capacity to hold cations can perform in the same flourishing way as the heavy clay soil with a high capacity. His school was developed over decades by his followers (Charles Walters, Neal Kinsey and many others) and over the years the school has proven to be valid for many types of soils or climates. The ratio or desirable concentrations were estimated for many minerals. The precise number could be slightly different based on school branches (used test), but the idea is always the same: measure the concentration, set the desired value based on soil capacity, and address deficiency or deal with excesses, if possible.
This led to another question, how to measure the concentration? One can observe deficiencies or excess symptoms in the plant or observe pioneering plants that are doing well in poor soil (for more details see Weeds, Control Without Poisons by Charles Walters). Good information can lead to a forecast of required nutrients, but this will require profound observation skills and years of experience. The best and easiest method for getting information is a simple soil test. Just send a soil sample to a laboratory and let professionals do the job. After all, the results are worth every penny. They can send you a result only or, for an extra fee, they can give you a recommendation of amendments. I am not going into details about various tests for the various types of soils. Please, ask a local extension agent or use resources on the web. Just be aware of free tests, because they usually provide insufficient information. A good soil test should contain the following: total cation exchange capacity value of your soil, percentage of organic matter, Sulphur (S), Phosphor (P), main cations – Calcium (Ca), Magnesium (Mg), Potassium (K), Sodium, and other microelements – Boron (B), Iron (Fe), Manganese (Mn), Copper (Cu), Zinc (Zn), and optionally for the first-time test also Cobalt (Co), Molybdenum (Mo), Selenium (Se) and Silicon (Si). Some of these elements are not essential for plants, but they can improve beneficial biological activities. For example, Cobalt can improve nitrogen fixation by nitrogen-fixing bacteria that live in symbioses with legumes, or Selenium can improve resistance to pathogens and herbivores and is essential for our immunity. Both minerals are deficient in my area. This is also a reason why grains from our region (Central Europe) contain much less selenium than grains from Canada or USA (or Scandinavia, where the deficiency was fixed decades ago).
I prefer the procedures presented by Steve Solomon (see the Intelligent Gardener book referenced below). He built procedures for the most common soils (acidic, with excess cations, and calcareous soils) and the process is quite simple.
Do the fizz test (with vinegar) and decide whether to use Mehlich 3 test or AA8.2 test (a soil test for normal or calcareous soil).
Send a soil sample to a lab.
Calculate desired values of your soil based on the total cation exchange capacity of your soil and calculate deficiencies or excesses of minerals (desired values for tree soil types together with a detailed description you can find in a worksheet pdf file below).
Check yearly limits for application of missing elements.
Select and calculate the weight of amendments that supply deficiencies or suppress excesses (if possible).
Buy and apply amendments
For a reasonable price and effort, you can fix your soil. I am sending samples to Logans Labs, US (loganlabs.com). The delivery costs 7 €, and the standard soil test with extra elements costs $ 30. If you know a better lab, please let me know.
Here is an example of my last test (Figure 2) for a new field I rented for free last year by the grace of God. The few important numbers I would like to share with you are TCEC 13.95 (M.E.), pH 6.6, and Sulfur 31 ppm. Soil pH tells me that I will use an acid soil worksheet (page 19 in the worksheet pdf file below). The most important information that you need to know is unit conversion ratio. Approximately, the concentration of 1 ppm = 2 lb/ac/6in of soil depth = 2.24 kg/ha/15 cm of soil depth. I said approximately because the number slightly changes with the density of the soil.
Figure 3. A part of the soil report from Logan Labs.
(To view the whole report, download the pdf file in the "Other Resources" section)
My 31 ppm of Sulfur equals 69.4 kg of Sulfur per ha per 15 cm of soil depth (31*2,24=69,4). That means that my soil contains 69.4 kg of available Sulfur per 1 ha in the top 15 cm of soil. An acid soil worksheet tells me that my target level of Sulfur is 70 lb/ac (for TCEC>10), which is 78,4 kg/ha/15 cm of soil depth of Sulfur. 78,4 kg I need – 31 kg I have = 47,4 kg I need to add, of course per ha and mixed it in 15 cm of soil depth. Now is the time to check the safety yearly limit for adding elemental Sulfur. It is 100 lb/ac/6in (page 20 in the worksheet pdf file) or 112 kg/ha/15 cm. So, it is fine to apply 47,4 kg.
There are few resources of Sulfur, and the choice is usually based on a level of Calcium and/or other major cations (Mg, K, Na). Since the soil has been lacking Calcium, and the Calcium is at the level of 60% of capacity, I will use Calcium Sulfate (Gypsum powder) that is listed in the list of amendments allowed in organic farming. For a low level of Ca less than 60% of TCEC, Gypsum is not effective and elemental Sulfur – Ag Sulfur should be used instead. Gypsum contains 17% of elemental Sulfur and 20.5 % of Ca and that means I must apply 279 kg/ha/15cm of Gypsum (47,4 kg / 0,17 = 279 kg). Please note that adding Calcium to the soil in the form of Gypsum does not change the pH of the soil. An ideal time for applying Gypsum is fall. It takes some time for the decomposition of S and Ca done by bacteria into available form.
In the same way, you can adjust the deficiencies of all elements. I am wondering how many readers get to the point to calculate required amendments. So, I have a task/homework for you. The test result shows my soil is missing 227 ppm of Calcium. Calculate how much Ag lime I have to apply if you know that Ag lime contains 35% of Ca and 2% of Mg. Please, send your answer to the email below. If points 3 – 5 are too challenging for you, find a local soil analyst or try to find a lab that provides results with recommendations or use an online (paid) calculator (see below).
Once you balance your minerals, living biology will keep them at the optimal level. The overall goal is to be independent of any amendments. And remember, ideal soil is just one leg of the healthy plants. You must build the biology of your soil and promote good photosynthesis in the plants. These other two legs could be explained some other time.
As a steward of the soil, you can turn the wheel of a healthy living system and keep watching how magnificent the Creator is.
Dr. Rastislav Lagana works at the Technical University in Zvolen, Slovakia, as a teacher, and Wood Science is the area of his expertise. He is also a hobby gardener. Together with his wife, they find joy in gardening for family and friends. Rastislav volunteers as a lecturer of Health Clubs supported by the Health Division of SDA in Slovakia providing public services in sharing and promoting practical information about organic gardening methods and a healthy lifestyle. If you will have any questions, suggestions, or an answer to your homework, please do not hesitate to contact him at rastolagana@gmail.com.
Other Resources:
Complete soil test report:
https://www.audioverse.org/en/series/1226/soil-fertility-advanced - a great resource, hours of audio lectures from Whitmar McConnell (soil analysts) about the ideal soil.
The Intelligent Gardener: Growing Nutrient Dense Food, by Steve Solomon, Erica Reinheimer. Publisher: New Society Publishers.
Calculator of amendments: growabundant.com/organicalc (it is an online paid calculator). Please note, that I have no personal connection to the authors of the website. I did not even try the software, so I cannot guarantee that the calculation is right.
And few other good books about ideal soil:
The Art of Balancing Soil Nutrients: A Practical Guide to Interpreting Soil Tests, by William McKibben
Hands-On Agronomy, by Neal Kinsey and Charles Walters
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