What do you find when you look at the soil? What do we pay attention to when we look at the soil?

Looking at the soil, you can see that the texture of the soil is different. Classification of soils by soil texture is generally divided into three main categories: sandy soils, clayey soils, and loam soils.

Sandy soils are soil particles with a diameter of millimeters accounting for 50% to 90% of the soil particles. The sandy soil has good aeration and water permeability, low tillage resistance, rapid soil temperature change, poor water and fertilizer retention ability, and is prone to drought. Soil containing more than 80% particles with a diameter of less than millimeters is called clay, and the properties of clayey soils:

The sediment content is small, the particles are fine, the water seepage speed is slow, the aeration performance is poor, the soil structure is compact, and the tillage resistance is large, but the water and fertilizer retention ability is strong, the fertilizer supply is slow, and the fertilizer effect is lasting and stable. Loam is the best soil quality because it is sandy and clay. Nature of loam:

The sand content is average, the particles are average, the water seepage rate is average, the water retention performance is average, and the ventilation performance is average. The loam soil is loose, easy to cultivate, has good water permeability, and has a fairly strong ability to retain water and fertilizer, which is suitable for planting a variety of Chinese herbal medicines.

In particular, Chinese herbal medicines with roots and rhizomes are most suitable for cultivation in loam soils.

Substances contained in the soil: The soil contains the roots of dead plants, fallen leaves, rocks and sand. There are roots and shoots of live plants, as well as ants and earthworms.

and other small animals or animal carcasses. These branches and animal carcasses are not currently a component of the soil, and if they all decay, they become a component of the soil, called humus.

Humus is the black substance produced when plants and animals decay, and it is a good nourishment. There is also salt in the soil, which is a mineral dissolved in water. They are all essential nutrients for plant growth.

Just as humans need nutrients to grow, plants in the soil need nutrients to grow, and humus and salt are both essential nutrients for plant growth.

What's in the Soil is based on "Studying Soil" in the "Mix" unit 3 and "Do Rocks Change Shape" in the 4th "Rock and Minerals" unit. The first part of the textbook, "Finding the Composition of Soil", is a three-step process, which involves observing moist soil, dry and crumbled soil, and soil sedimentation experiments. Let students understand that there are visible and invisible substances in the soil, and that soil is a mixture of sand, pebbles, clay, humus, water, and air.

The second part of the textbook, "Soil and Life", vividly describes the relationship between soil and life through a picture.

2. Instructional design.

1) Teaching objectives.

1. Scientific concepts.

1) The weathering of external forces and the action of living organisms make the rock eventually turn into soil.

2) The soil contains particles of different sizes (pebbles, sand, clay) formed by weathering rocks, animal and plant residues, as well as humus, water and air.

3) When the water flows, it can carry the soil particles to move with it, and when the water flow is still, the carried material will also be deposited, generally speaking, the heavy particles are deposited first, and the light particles are deposited later.

Summary. 1. After the formation of the soil, each soil layer is different in composition and qualitative nature, so it is reflected in the morphological characteristics of the profile, and each layer is also different. In the field, through the observation of soil profile morphology, some important qualities of soil can be determined.

The important morphological characteristics of soil are: solidity, porosity, moisture, new organisms, intrusives, animal porosity, etc. 2. Soil color is the expression of the internal material composition of the soil in the external color.

Due to the different mineral and chemical composition of soils, the colors of soils are diverse. Soil pigmentation is usually a very obvious feature when identifying soil layers and soil classifications. The soil color se is named using the Munsel face se naming system, which compares the soil block with the standard color se card and gives the name.

Hello dear, glad to answer for you! The characteristics of the soil specimens can be observed from the aspects of soil color, particle size, and small insects inside.

1. After the formation of the soil, each soil layer is different in composition and qualitative nature, so it is reflected in the morphological characteristics of the profile, and each layer is also different. In the field, through the observation of soil profile morphology, some important qualities of soil can be determined. The important morphological characteristics of soils are:

Solidity, stare chain porosity, humidity, neobodies, intrusives, animal holes, etc. 2. Tuzhou Dan soil face SE is the expression of the internal material composition of the soil in the external SE color. Due to the different mineral and chemical composition of Kaisun soil, the color of the soil is diverse.

Soil pigmentation is usually a very obvious feature when identifying soil layers and soil classifications. The soil color se is named using the Munsel face se naming system, which compares the soil block with the standard color se card and gives the name.

Soil moisture is the moisture content of the soil, and the degree of soil wetness is distinguished when the profile is observed in the field.

Generally, it is measured by dry, slightly moist, moist, damp and wet, and it is dry when it is tested by hand, and there is a significant cooling feeling;

Slightly cool, Cao Ke丨 Jiu Cha Xun intestinal demons do not feel moist for a little moist;

Obviously moist, can be pressed into various shapes without wet marks for moisture; When squeezed by hand, there is no water leaching, and there are wet marks for moisture;

Squeeze it by hand, and the water will appear wet.

Balabalabala and Balababara Balababala Balaba.

The topsoil layer can be divided into tillage layer and plough bottom layer, also called humus-leaching layer, which is the tillage layer of ripening soil; In forested areas there is a layer of litter. The upper surface soil layer, also known as the tillage layer, is a soil layer with a high degree of maturation, with the best fertility, tillage and production performance; The lower topsoil layer includes the plough layer and the uppermost part of the core soil layer (also known as the semi-cured layer).

1. Tillage layer: the soil layer most strongly affected by tillage, fertilization and irrigation, with a thickness of about 20 cm. The tillage layer is susceptible to the influence of production activities and surface organisms and climatic conditions, and is generally loose and porous, with frequent alternation of dry and wet, large temperature changes, good permeability, fast material transformation, and more available nutrients.

The root system is mainly distributed in this layer, generally accounting for more than 60% of the total root system.

2. Plough bottom: located under the tillage layer, about 6-8 cm thick. The typical bottom layer of the plough is very compact, with small porosity, few non-capillary pores (macropores) and more capillary pores (small pores), so the ventilation is poor, the water permeability is poor, the structure is often sheet-like, and even there is a visible horizontal bedding.

This is often formed by the pressure of ploughing animals and ploughs, as well as the deposition of clay particles through precipitation and irrigation.

The core soil layer is also known as the "raw soil layer". is the middle layer of the soil profile. It is located between the topsoil layer and the subsoil layer.

It is formed by a substance that has been subjected to leaching of topsoil. It usually refers to the layer of soil below the topsoil layer to a depth of 50 cm. Due to the movement and deposition of materials, the topsoil layer and the core soil layer can best reflect the characteristics of the soil formation process.

In cultivated soils, the structure of the core soil layer is generally poor, with a lower nutrient content and few plant roots. The core soil layer of dryland soil generally maintains the morphology and characteristics of the natural soil alluvial layer before reclamation and planting, and the changes caused by cultivation are small. The core soil layer of paddy soil is mostly developed into a markings layer with a prismatic or prismatic structure under normal circumstances.

The core soil layer is located below the bottom layer of the plow, the thickness is about 20-30 cm before the wheel, and the layer can also be compacted by a certain pressure of plough and livestock, but it is not as compact as the bottom layer of the plow. In the cultivated soil, the core soil layer is an important layer that plays the role of water and fertilizer retention, and is the main layer of water and fertilizer in the later stage of growth. The number of roots in this layer accounts for about 20-30% of the total number of roots

The subsoil layer, also known as the parent layer, is a layer of soil that is not affected by tillage and maintains the characteristics of the parent material. If the parent material of the soil is rock weathering debris, the subsoil is often mixed with these detrital debris. The subsoil layer is below the core soil layer and is generally located at a depth of 50-60 cm below the surface of the soil.

This layer is less affected by the surface climate, but it is also relatively compact, with a slower material transformation, less nutrients available, and less root distribution. This layer of soil is often referred to as raw or dead soil.

Hello! Soil fertility refers to the ability of the soil to continuously provide and coordinate the requirements for water, fertilizer, gas, heat, etc. Soil fertility is the basic and essential property of soil.

The four major fertility factors are commonly referred to as soil moisture, soil nutrients, soil air and soil heat.

Various fertility factors are inseparable from each other. Therefore, soil fertility is a comprehensive manifestation of various fertility factors and is an important factor in determining crop yield. At present, it is not possible to generalize soil fertility in terms of exact quantities, and the yield of crop species on soil without any fertilizer, i.e., blank yield, is usually used as a comprehensive indicator of soil fertility.

Generally speaking, the high yield of blank indicates that the soil has strong fertilizer supply capacity and high fertility; On the contrary, it indicates that the soil fertilizer supply capacity is weak and the fertility is low.

Refer to China Agricultural Extension Network

I hope my answer is helpful to you and I wish you a happy life!