Do you really understand the difference between soil and soil? Soil covers the land surface and can support plant growth if external conditions such as light, temperature, and precipitation are sufficient. Its parent material is rock weathering that is transported and accumulated

Do you really understand the difference between soil and soil?

Soil covers the land surface and can support plant growth if external conditions such as light, temperature, and precipitation are sufficient. Its parent material is rock weathering that is transported and accumulated by water or wind. It is formed during a certain period of time through the interaction with climate, biology (including human factors), topography and other factors. Soil is at the core of the ecosystem. In addition to nurturing plants and other terrestrial organisms, soil can also decompose fallen leaves and animal remains and maintain normal biogeochemical cycles of elements. Soil is one of the elements that constitute the environment along with the atmosphere and water.

Nowadays, the words "soil" and "soil" are generally used separately. In other words, "soil" is formed after weathering of rocks; after weathering of rocks into fine particles, if they are in a state suitable for plant growth due to biological effects, they are called "soil", which is clearly distinguished from "soil".

The formation of soil

Scientists used radioactive elements to determine the age of meteorites . They also analyzed the lunar rocks brought back by the Apollo program and speculated that about 4.6 billion years have passed since the birth of the earth we live in. It is generally believed that when the earth was first born, the surface of the earth and the surface of the moon were not much different, but now they have become completely different. This difference is caused by the fact that there is no air and water on the moon, so no living things were born; while on the earth, rich and diverse living things were born.

Since there is no air (vacuum) on the moon's surface, it is greatly affected by the sun. Strong ultraviolet rays and temperature differences (around 130°C to minus 170°C) cause rocks to weather into fine particles (powder). Such particles are called dust and are not considered soil.

In contrast, the temperature difference on the earth protected by the atmosphere is very small (about 40°C to minus 40°C). In addition, the earth has water, microorganisms can inhabit weathered rock particles, decompose, condense, and polymerize organic matter to form humus, thereby forming an environment suitable for biological growth - soil.

The difference between soil and soil

From soil to soil

In the process of changing from soil to soil, biological activities are an indispensable factor. The first appearance of living things on the earth was about 4 billion years ago; and the first appearance of soil on the earth should also be at this time. After soil and living things appeared together on land, their relationship has been inseparable until today.

Rocks turn into soil. In addition to physical reasons such as collapse, living things also have the power to turn rocks into soil. It is generally believed that the organisms that can turn rocks into soil are mosses ( lichens ) that require a little nutrients on the rocks to grow. We can often see rocks covered with moss on mountains or in ancient temples. Under the moss, a thin layer of trace amounts of soil has actually appeared, and it is soil containing clay, microorganisms and organic matter.

Soil born from rocks (Figure 1)

When water accumulates in the depressions or cracks on the rock surface, creating an environment with moderate moisture, moss that can use sunlight will begin to invade. As the moss gradually proliferates, the rock surface covered with moss slowly turns into soil. At this time, various microorganisms that can utilize inorganic or organic matter proliferate in the soil. Under the action of these microorganisms, the properties of the soil will gradually change into an environment suitable for plant growth, that is, "soil".

When grass appears on the new soil, the soil will slowly increase due to the action of grass roots and microorganisms, becoming an environment suitable for the growth of shrubs. Then tall trees will appear, and plant communities will gradually emerge.

The changes in plant communities on the ground also have a great impact on the environment below the ground.The roots of various plants stretch downward and secrete organic acids that can dissolve rocks; after withering, they not only provide an energy (food) source for microorganisms, but also create tiny gaps. The action of plant roots promotes the decomposition of rocks and the activation of microorganisms, causing humus to accumulate and continue to produce new soil. Even deeper rock layers gradually become soil layers.

After large plants begin to grow, fallen leaves and other organic matter bring more supplies to the surface, accumulating a large amount of humus, making the soil more fertile.

After a period of time, the nutrients in the soil begin to leach; after the nutrients are lost, the soil will gradually become an environment unsuitable for plant growth, that is, "soil". As mentioned above, soil is born and disappears, disappears and is reborn again and again over hundreds to tens of thousands of years.