As we talk about plant nutrition, we need to think beyond N-P-K to understand what healthy, nutrient-dense plants need to thrive. Every bag, bottle, or jug or synthetic fertilizer on the market has those three numbers printed on the side that represent the amounts of nitrogen, potassium, and phosphorus that the product can deliver. Yes, plants need these three elements, but there is far more to providing for healthy, nutrition-packed plants than just those three elements.
N-P-K represent what is commonly known as the primary elements needed for healthy plants. There are, however, many more elements that must be present and available for plants to produce fruit and vegetables rich in the dietary nutrients that lead to a healthy diet.
The so-called secondary nutrients, calcium, magnesium, and sulfur, are just as important as the primary elements. The third set of elements, termed trace elements, include iron, boron, copper, chlorine, manganese, molybdenum, zinc, cobalt, and nickel. This generally accepted breakdown is based on the amounts of the elements needed by the plant and the characteristics of the elements themselves. We will discuss this more in subsequent articles.
Industrial agriculture, which began its rapid rise to dominance in the middle of the 20th century, is the real foundation of the focus on N-P-K. As farmers began to farm larger and larger swathes of land using the then currently accepted practices of deep tilling each year, they noticed that over time, their crops were not producing yields comparable to earlier years. Ag researchers soon found that the soil, due to the tillage practices and intense farming techniques, was being depleted of all nutrients. The scientist’s answer was to put back into the soil, in synthetic form, what they considered to be the most important missing nutrients, nitrogen, potassium, and phosphorus. The application of synthetic fertilizers allowed the plants to appear vigorous and healthy. Unfortunately, the lack of the other secondary and trace elements soon meant that the public, who depend on the farmers for their food, were getting beautiful products with nutrient values that were still reduced. Just like the plants, our bodies require all those trace elements, and when they are not present in an available form, the body suffers.
We have, essentially, been starving ourselves for the last 70 or so years amid the most productive agricultural cycle the world has ever known.
A simpler answer
The answer to this is to find a method of production that puts back into the soil everything the plant requires, in the right amounts and the right form. The simple answer to this problem is to do what nature has been doing for thousands and thousands of years.
We know that tilling destroys the microbiome that exists in the upper layers of the soil. This microbiome, the bacteria, fungi, and small creatures that co-exist are essential for healthy soil. Without healthy soil, you cannot grow healthy plants.
We know that continual tilling and monocultural ag practices deplete the soil of the 18 essential nutrients.
We know that the application of the chemical trinity N-P-K in synthetic form, over time, creates its own set of problems including a gradual build-up of salts in the soil, a loss of bacteria and fungi, and the continued depletion of the other secondary and trace elements needed in the soil.
On the other hand, adopting no-till practices, the use of cover cropping, and a sound crop rotation plan can eventually return the soil to a healthy balance and re-establish the soil biome. A whole new field of study, regenerative agriculture, is now underway across the world.
The small Urban Gardener
But, you ask, how does this affect me as a small urban gardener.
The answer is that you can adopt the same practices in your garden. Quit using any synthetic fertilizers. In fact, quit using any synthetic products at all. Adopt a no-till approach to your garden. Never leave bare ground in your garden. Cover crops and mulching are the secrets here. Healthy soil needs living roots in the soil year-round. Keep something growing in your garden all year. Let nature do as much of the work as possible. Compost is the key. Everything that grows contains the proper balance of elements. By composting, you are creating soil that contains that perfect balance of nutrients and trace elements. Returning that compost to your garden helps return your soil to that balance.
Feed the Soil
Stop thinking about feeding the plants and start thinking about feeding the soil. It is the bacteria, fungi, and small animals in the microbiome of your soil that feeds your plants. There is a symbiotic relationship between the plants and all those organisms growing in your garden soil. Those organisms react to signals from the plant sent by way of the exudate from the roots and give the plant exactly what it is looking for at the moment. The exudates from the plant continue to nourish and support the microbiome inhabitants. Feed the soil, and it will feed your plants.
Plant nutrition is much more than three letters on a bag of fertilizer. As we delve further into this topic, we will examine the interaction of the plants and the microbiome, the way the balance of nutrients affects the plant’s health, and each of the required elements in detail. Links and Resources
Links and Resources
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