What color is the soil you commonly encounter? The answers from people from different regions may vary. In fact, there are more than 60 types of soil in China's vast territory, with their distribution, texture, composition, and color differing from each other. For example, the black soil of the Northeast Plain, the loess of the Northwest Plateau, the paddy soil of the Jiangnan Water Towns, the red soil of the southern hills, the purple soil of the Sichuan Basin, the calcium-rich soil of the Inner Mongolia grasslands, the arid soil of Xinjiang, the alpine soils of the Tibetan Plateau, the mountainous forest soils stretching from north to south, and the "bird droppings soil" of the South China Sea islands, etc.
The soils in different regions are caused by different natural conditions. The color of the soil can reflect the internal characteristics of the soil and is an important basis for classifying soil layers and studying soil properties. The types of compounds contained in the soil are closely related to the color of the soil. For example, white soil is due to the fact that some rocks only contain a single color or minerals of the same color. After the rocks are weathered, white soil is formed. Northern China is a region with a high latitude, mild and dry climate, and high evaporation compared to precipitation. The weathering effect is weak, and the soil is in a weak leaching state. Most of the soluble substances such as chlorine, sulfur, sodium, and potassium in the soil are leached away, while silicon, iron, aluminum, etc. in the soil are not leached away. Calcium combines with carbonic acid produced by plant decomposition to form calcium carbonate aggregates in the soil, which respectively present chestnut or brown colors, hence called chestnut-calcium soil and brown-calcium soil. Before human development, these places' grassland plants provided the soil with a large amount of organic matter every year. The accumulation of organic matter formed fertile black-calcium soil.
It can be seen that due to the different climate, terrain, temperature, and water conditions in various regions, a variety of soils are formed. And the composition of the soil also has an important impact on local agriculture. The colorful soils not only show the beauty of nature, but also offer humans a unique "scenery".