Porous loamy soils teem with life and are the richest and most fertile of all soils. Loamy soils contain a balance of the three main soil types: sand, clay, and silt soil. They are riddled with organic matter that retains water and creates the perfect nutrient-rich environment for plants to flourish.
Each soil type serves a different purpose and plays an important part in the ecosystem.
However, not all soils have good fertility.
For example, Histosols are useful for decomposing plant and animal remains that have been left within the soil, but the soil’s wet texture makes it inefficient for growing or planting.
Generally, soil falls into four categories; loam, silt, clay, and sandy.
Loamy soils are very fertile as they are good at retaining moisture, but also have good drainage, therefore still allows air to reach the roots.
Silt soil, again, is very fertile. It is a light soil, and similarly to loam, enables good retention and circulation.
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What Makes Soil Fertile?
Highly fertile soil will contain all of the primary nutrients to aid a plant’s health such as; nitrogen, potassium, and phosphorus.
Other nutrients are also required, however, not in such large quantities.
Some of these include; calcium, iron, and sulfur.
The United States, India, and China are all leading countries in soil fertility.
What Are The Most Fertile Soil Types?
Alfisols make-up more than 10% of the world’s ice-free land area, and occupy 13.9% of the land area in the US.
Alfisols are easier to maintain and easier to keep fertile than other soils.
They can survive with less water and are commonly found in humid climates such as Australia, Africa, and South America.
They are used for agriculture and silviculture purposes and have a clay subsoil.
Clay has an elevated level of iron and aluminum, and since Alfisols are normally formed in forests, the fallen leaves contribute to its fertility.
The soil profile has a rich brown surface and a reddish subsurface.
This soil is ideal for growing corn, wine grapes, and wheat.
Mollisols are considered to be one of the most fertile soils on Earth.
This is due to the organic matter that has been derived from plant roots, as well as the clay soil.
It is grassland soil and found in Europe, China, Russia, and The Americas.
The soil horizons from sand, limestone, and loess.
The organic matter of the soil can reach as deep as 27 inches, whereas the standard is around 6 inches.
Historically, organisms such as earthworms and ants have greatly influenced this.
Altogether, mollisols take-up around 7% of the world’s land area.
Andisols are formed of volcanic ash.
They have a high content of glass and other colloidal materials.
Since this soil is generally quite young, it also has a high level of fertility.
They are good for supporting intense farming/cropping (such as in rice fields) and can last even in some of the world’s densest populations.
They are also used for farming tea/coffee, tobacco, maize, and fruit.
Unlike Alfisols and Mollisols, which have a reasonably large land coverage, Andisols only makes up 1% of the Earth’s ice-free ground.
It is mostly found in South America, Java, Japan, and the North Island of New Zealand.
Soils that are derived from volcanic ash typically are very fertile.
The minerals it contains generate positive ions which help feed plants and other lifeforms.
How To Improve Soil Fertility
Improving your soil fertility can be done by adding more organic matter, using compost or manure.
This will increase the soil biology.
Make sure the top of the soil is firm by treading it with your foot so that rain or other weather conditions do not erode the organic matter.
Focus on the upper layers of soil, as this is where the majority of soil life is located.
When it comes to planting/farming crops, soil high in nutrients, with a combination of good water retention as well as good air circulation, is the best option.
Many gardeners face the issue of their soil not having good enough drainage, which can cause plants to drown.
Looking after your soil by adding organic matter or constructing a draining system will also help your plants to grow.
In order for plants to be healthy, they need a steady stream of nutrients.
There are many contributions to what makes a soil fertile including the organisms that live within the soil, and the texture of the soil.
The fewer nutrients a soil has, the more negative ions it will have and the fewer plants will thrive within it.