It’s true that plants grow from the top-down. In other words, it uses water and carbon dioxide from the air to grow. But you can’t remove key nutrients like:
- Nitrogen (N)
- Phosphorus (P)
- Potassium (K)
Because if you deplete the soil from these nutrients, this deprives the plants of growth. For example, this is common in crop production and tree harvesting areas.
“This is why farmers rotate crops and allow periods of rest or “fallow” to replenish the soil with nutrients. If they can’t do it this way, then farmers use chemical and natural fertilizers to replace nitrogen.”
Nutrients from soil organic matter
Plants absorb nutrients directly from soil organic matter. For example, nitrogen (N), phosphorus (P), and potassium (K) are vital for plant survival. Together, these three soil nutrients make up NPK.
To a lesser extent, plants need calcium (Ca), sulfur (S), and magnesium (Mg) from the soil. But how do these nutrients contribute to plant growth?
|Element||Major Uptake Source||Purpose|
|Nitrogen (N)||Soil organic matter from soluble NO3 and NH4; Atmospheric N2 from nitrogen fixing species||Chlorophyll and plant leaf development and everyday functions from DNA, RNA, and proteins.|
|Phosphorus (P)||Soil organic matter; Soluble phosphorus.||Root growth and helping withstand environmental stress.|
|Potassium (K), Calcium (Ca), and Magnesium (Mg)||Soil organic matter: Soluble K+, Soluble Ca3+, Soluble Mg2+||Plant strengthening, growth, and disease resistance.|
Soil Nutrients Deficiency and Replenishing
Healthy soil requires healthy nutrients. If your soil is depleted or missing some of the key nutrients required for plant growth, you might need to amend it with fertilizer. To stay healthy and fertile, fertilizers can also come in.
Organic matter plays an important role in the health of our soil. It forms the foundation of the food web, provides the essential structure for soil organisms, and is a vital component in maintaining healthy soils.
If you are interested in learning more about soil science and how it relates to agriculture, here are some online courses that can help you get started (and looks great on a CV/resume)
Or if you have any questions, please give us a shout in the comment box below.