Soil Fertility: Why is it Important?

You may think that a topic about soil fertility is boring. I did. That is, until I learned that fertile soil is crucial for our existence!

Soil plays an essential part in our survival since it is connected to our food supplies. 

Here’s why:

  • Fertile soil ensures plant survival. Fertile soil holds plants in place while providing them with the life-supporting nutrients that they need to survive.
  • Plants ensure our survival. The food (nutrients) that all living organisms, including humans need in order to survive comes immediately or indirectly from plants.

So, soil fertility is important. Without fertile soil we would have no plants. Without plants we would have no food. And without food, there is no us, since we need food to survive.

…Let me answer some questions you might have about plants first...then I will return to the discussion about soil…

How Does All the Food that We Depend on for Survival Come Immediately or Indirectly from Plants?

Autotrophs such as green plants are called producers since they make their own food through photosynthesis.

During photosynthesis, producers use solar energy and the inorganic nutrients carbon dioxide and water to produce organic nutrients called carbohydrates.

These organic nutrients not only fuel the vitality of the plants that produced them, but also provide nearly all living organisms with the energy that they need in order to survive.

Here’s why...

  • Heterotrophs (humans, all animals) are consumers that cannot make their own food (organic nutrients) from inorganic nutrients.
  • Heterotrophs must obtain the organic nutrients that they need for survival immediately or indirectly from the autotrophic producers that make them.
  • Heterotrophs consume these organic nutrients:

    • Directly when they eat the autotrophic plants that produced them.
    • Indirectly when they eat other heterotrophs that feed on autotrophic plants.

      (For example, a human may obtain these nutrients by drinking milk produced from a cow that had directly consumed these nutrients by feeding on plants.)

Therefore, plants provide all living things with the nutrients that they need in order to survive.

What Else Do Producers Make During Photosynthesis that We Cannot Live Without?

Carbohydrates such as glucose produced during photosynthesis supply not only producer plants but nearly all living organisms with the energy that they need in order to live.

However, glucose cannot immediately fuel living things with energy because it contains too much of it.

To use the energy obtained from photosynthesis, the majority of living organisms must undergo cellular respiration. During cellular respiration, glucose breaks down, releasing energy used to create ATP (adenosine triphosphate) molecules. Then, ATP supplies cells with utilizable levels of energy.

Autotrophic producers not only make organic nutrients but also emit oxygen during photosynthesis. Without this release of oxygen, cellular respiration could not occur and we would not be able to use the energy that fuels our survival.

How Does Fertile Soil Support the Life of the Plants that We Need in order to Survive?

...Now that I described how important plants are to us, I will return to the significance of soil fertility.

I already mentioned that we need plants in order to exist. And that fertile soil is crucial to our survival because it ensures that the plants we depend on can thrive. But how?

Fertile Soil Helps Plants Take Up the Ingredients Required for Photosynthesis

Fertile soil enables plants to absorb the inorganic nutrients (carbon dioxide and water) and sunlight required for photosynthesis.

Here’s why:

  • Carbon Dioxide and Sunlight. The structure of fertile soil is stable. This structure enables soil to prop up plants. When plants are bolstered up, the pores on their leaves (stomata) can absorb carbon dioxide and the chlorophyll pigments in the chloroplasts of their cells can soak up solar energy.
  • Water. The structure of fertile soil is spongy. This porous surface enables water to enter and to be retained so that it is available for plants to absorb with their roots. When plants take up water from the soil, it serves as an inorganic nutrient for photosynthesis. During photosynthesis, water converts into the oxygen that fuels cellular respiration.

*Sidenote:* Without soil, plants could not be held in place and be fed the nutrients that keep them growing.

However, soil also depends on the roots of plants to hold it in place. Without the presence of plants, soil erodes.

You can learn more about soil erosion here.

Fertile Soil Provides Plants with Additional Life-Supporting Nutrients

Plants not only absorb water, but also many other nutrients from the soil with their roots. Fertile soil provides plants with lots of additional "food" that supports plant life.

Functions of these nutrients involve: assisting with photosynthesis, stimulating and supporting growth, facilitating protein production, and protecting against disease. 

plant_nutrients

Plant nutrients found in fertile soil include:

  • Macronutrients. Plants need these nutrients in large portions. They include nitrogen, phosphorous, and potassium and often appear in fertilizers that have the label N-P-K.
  • Secondary macronutrients. These nutrients include calcium, magnesium, and sulfur.
  • Micronutrients. Plants need these nutrients in smaller servings. Some micronutrients include boron, copper, iron, chlorine, molybdenum, manganese and zinc.

View the chart above for details about these nutrients and their functions.

Soil Fertility Matters to Organic Farmers

The presence of various plant nutrients in soil increases soil fertility. So how does this plant food show up in soil?

Soil is nutrient-rich largely due to the activities of living things in soil. Although some of these organisms are microscopic, they play a major role in soil fertility.

Learn more about these beneficial organisms on the soil life page.

A significant way that organic farmers increase soil fertility on their crops is by preserving soil organisms. The preservation of the beneficial living things in the soil is also a technique that organic farmers use to conserve soil.

Click here to find my FREE e-book about soil conservation.

On the other hand, conventional farmers practice agricultural techniques that decrease soil fertility by harming soil organisms. Additionally, harming the beneficial inhabitants of soil is one of many ways that conventional farmers degrade soil.

Click here to learn in detail about soil degradation.

You can also find a brief summary of the differences between soil conservation and soil degradation on the soil erosion page.



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