There are Tusi and fields.

The soil is the soil and the field is the farmland.

Land, covered with soil to become land.

Land, with human farming activities, will become farmland.

Soil reference Reading @ Earth's skin: soil.

Northeast black land.

There are Tusi and fields.

The earthy, the spitting creatures of the earth.

Shuo Wen Jie Zi, written by Xu Shen in the Eastern Han Dynasty.

Soil is the material basis of the field, there is no doubt about it since ancient times.

Modern pedology also describes soil as a loose layer on the land surface of the earth that can grow green plants, which recognizes that soil is the basic material for plant growth.

From the point of view of time, there must be soil before land, and when can their first show on earth be traced back to?

According to the latest research results, at least 400 million years ago, aquatic plants began to land and form ferns, which accelerated the corrosion of rock surfaces and eventually created a suitable soil environment for the growth of other higher plants.

The emergence of soil has created forests, grasslands and wetlands, making the land lively and lively.

Formation of soil and evolution of plants.

(Alshan Shitang Forest).

In contrast, the development history of farmland is much shorter. Only when humans learn to cultivate can they have farmland. The earliest farmland may have been the wheat fields of the ancient Egyptians in the Mediterranean region 9,000 years ago.

As the Hemudu people learned to grow rice in the lower reaches of the Yangtze River 7000 years ago, paddy fields first appeared in China.

Hemudu Cultural site.

Good soil, good field.

As the saying goes, "one side of water and land raises one side of people", in fact, "one side of soil and one side of land" is also applicable.

In fact, the soil in nature is not "old-fashioned", but colorful. In ancient times, five-colored soil was used to symbolize the land of China.

The five colors of soil at the top of the Ming Dynasty in Zhongshan Park in Beijing are generally in line with the soil distribution in China.

The five-colored soil of Zhongshan Park in Beijing.

In the eastern region, there are many paddy, the soil is cyan, the red soil in the south is red, the purple soil is red, the dry soil and saline-alkali soil in the northwest is white, the soil in the north is black, and the hinterland of the Central Plains is loess plateau.

Bird's-eye view of Guanzhong Plain (eight hundred miles of Qinchuan).

Of course, there are not only five kinds of soil in our country, and the classification of soil is determined not only by color, but also by soil material composition and various properties.

According to the commonly used soil genetic classification in China, soils are divided into seven categories: soil class, subclass, soil class, soil class, soil genus, soil species and subspecies, including what we often call "black soil" and "red soil".

Dongchuan laterite (red soil) in Yunnan.

There are so many kinds of soil that the farmland they form has its own advantages.

"Yi Zhoushu training" mentioned that "the soil is suitable for the weather, all things walk", which refers to different types of soil, suitable for growing different crops.

Because different crops have their own growth characteristics, the degrees of fertilizer tolerance and barren tolerance are different, so they are also very picky about the stickiness, acidity and basicity of the soil.

Yuxian Xiaomi and traditional Paper-cut.

"Gongmi" produced in Yichuan County of Henan Province and Yuxian County of Hebei Province has been related to soil since ancient times.

The soil for planting tribute rice in these two places belongs to cinnamon soil. Cinnamon soil is located in the semi-humid area of warm temperate zone. because of its deep thickness and moderate viscosity, it is especially suitable for the cultivation of wheat and millet, coupled with the superior geographical and climatic conditions in these two areas. it provides unique conditions for the output of Gongmi.

Northeast rice.

For example, we all think that the rice in the northeast is delicious, and the black soil also plays an important role.

Because the black soil has a high content of organic matter, rich nutrients and loose soil, the rice produced on such soil is of course "greasy".

Yantai apple.

Such as apples in Yantai, navel oranges in southern Jiangxi and cantaloupes in Xinjiang, the output of these dominant crops must be inextricably related to the soil, in addition to topography, climate and other factors.

What native fertile land.

Although farmland is developed from natural soil, not any soil can be developed into farmland.

First of all, there must be flat terrain, because if the slope is large, terraces must be built to prevent soil erosion, and generally speaking, when the slope of the soil exceeds 25 °, it is not suitable to develop into farmland.

(horizontal screen viewing is recommended).

Secondly, the soil should have a certain thickness to store water and nutrients for the growth of crop roots.

In addition, there must be appropriate temperature and moisture to meet the "desire" for heat and water in the growth of crops.

Fertile land is simply understood as farmland that produces more and better grain, and what kind of soil can become fertile land? in the words of ordinary people, it is "strong" soil, that is, fertile and fertile soil.

Such soils generally have several things in common: deep soil, sufficient nutrients, moderate acidity and alkalinity, flat terrain, irrigation and drainage, and soil can become a good field only if it meets multiple conditions at the same time.

But now some people do not think so, saying that "crops with a flower, all depends on fertilizer," and the role of chemical fertilizer is more important than soil.

If the crops are to grow well, fertilization is the long-term practical experience of the working people, but in recent years, farmers have generally found that more and more chemical fertilizers are used, but the effect is becoming less and less obvious.

A warehouse with piles of chemical fertilizer.

According to statistics, the utilization rate of chemical fertilizer in China is only 30%-35% for nitrogen fertilizer, 10%-25% for phosphate fertilizer and 35%-50% for potash fertilizer.

Although the massive application of chemical fertilizer can temporarily improve the soil fertility, but the soil structure and other properties are destroyed, it is only "empty fat" at this time.

Artemisia mandshurica (legume, important green manure crop and livestock feed).

Replacing part of chemical fertilizer with organic fertilizer and adopting conservation tillage methods such as rotation, fallow and no-tillage can make the soil fertility really strong.

Therefore, under the conservation tillage system, give full play to and maintain the natural fertility of the soil, reasonable application of organic fertilizer and chemical fertilizer, any soil may become a good field.

Ten thousand mu of Ziyun Ying blossoms.

(Huai'an, Jiangsu Province, planting Ziyunying organic green manure instead of chemical fertilizer).

Man and land are in harmony, and the land power is always new.

In the northeast of Heilongjiang Province, Sanjiang Plain, which is alluvial from Songhua River, Heilongjiang River and Wusuli River, is an important commodity grain base in China, but a kind of low-yield soil is generally developed here.

The surface of this soil is a layer of fertile black soil, but this is only an illusion, a spade down is a hard white soil layer, called white serous layer.

White serous soil.

This layer of soil is hard and impervious, which makes it difficult to root down. It is a "hard bone" that hinders the growth of crops, and it is also the soil of Sanjiang Plain.