What are sandy soils, clay soils, acidic soils, and alkaline soils? What s the difference?

Sandy soil has the least soil content and low viscosity, which is not suitable for the growth of most plants.

The clay is sticky, there are few voids in the soil, and it is not easy to ventilate and leak, which is suitable for breeding.

Loam soil is the best soil for the growth and contraction of plant roots, with high nutrient content and easy loosening.

Alkaline earth refers to carbonate or biphosphate.

Soil, pH.

It is alkaline. Saline-alkali soil has low organic matter content, low soil fertility, poor physical and chemical properties, and anions and cations that are harmful to crops.

Many, not easy to promote seedlings.

Acidic soil is a general term for soils with a pH value of less than 7. Including brick red soil, red soil, red soil, yellow soil and dry red soil.

1. Sand refers to the soil composed of more than 80% sand and less than 20% clay. Generally refers to soil with a lot of sand. This kind of soil is loose and has good water permeability and air permeability, but it has poor water and fertilizer retention ability, and needs to be improved when cultivating. Not suitable for the growth of certain plants.

2. Clay, also known as clay, is a clayey soil with few sand particles, and it is not easy for water to pass through it to have good plasticity, and the particles are very small (<2 m) plastic aluminosilicate. In addition to aluminum, clay contains small amounts of magnesium, iron, sodium, potassium and calcium, making it an important mineral raw material.

3. Soil, also known as loam, refers to the soil with moderate content of clay, silt and sand particles in the composition of soil particles, and the particle size is between to. The texture is between clay and sand, and has the advantages of clay and sand, with good aeration and water permeability, water retention and thermal insulation performance, drought and waterlogging resistance, strong stress resistance, wide adaptability, long cultivation period, easy to cultivate into high-yield and stable-yield soil, and it is also an ideal agricultural soil.

4. Acidic soil is a general term for soil with a pH value less than 7. Including brick red soil, red soil, red soil, yellow soil and dry red soil.

5. Alkaline

soil) refers to soil with a soil pH value greater than 7; That is, the concentration of hydroxide ions in the soil solution is greater than the concentration of hydrogen ions, which practically refers to the soil with a pH value above it.

Generally, it includes three types: calcareous soil, saline soil and alkaline soil.

The properties of soil are divided into three main categories:

1.Scattering: There is no bond or weak bond between the particles, there are a large number of pores, and it can be permeable to water and air.

2.Multiphase: Soil is often a three-phase system composed of solid particles, water and gas, and the changes in quality and quantity between the three phases directly affect its engineering properties.

3.Natural variability: Soil is a multi-mineral assemblage formed by the evolution of a long geological history in nature, which is complex, uneven, and constantly changing over time.

The engineering properties of soil are mainly as follows:

Looseness: After the excavation of natural soil, its volume increases due to looseness, although it is vibrated and tamped, it still cannot recover its original volume, which is the looseness of soil.

Permeability: Refers to the ease with which water flows through pores in the soil.

Compressibility: After the loose soil is transported and filled, it will be compressed, and the compressibility of the general soil is expressed by the compressibility rate of the soil, and the compressibility rate of the soil is related to the dry density of the soil.

Moisture content: is the ratio of the mass of water in the soil to the mass of solid particles, expressed as a percentage.

Compactness: It is to indicate the degree of compactness of the soil, and the dry density of the soil is used in engineering to reflect the relative degree of compactness.

1.Natural water content

The natural moisture content of soil indicates the degree of dryness and wetness of the soil, and refers to the ratio of the weight of water in the soil to the weight of soil particles in the natural state. The greater the water content of the soil, the more humid the soil, and the more unfavorable it is for construction.

2.Conversion of looseness to earthwork volume.

Looseness: After the soil is excavated, the tissue is destroyed, the volume increases, and even if it is compacted, it cannot recover its original volume, which is called the looseness of the soil, which is expressed by the looseness coefficient.

Looseness coefficient: the volume in the loose state after excavation is called the imaginary volume, and the volume that is not compacted after backfilling is called the loose filling volume. The ratio of the volume of earthwork in various states to the volume in the natural state is called the looseness coefficient of soil.

According to the looseness coefficient, the volume of soil in various states can be converted according to the quota provisions.

Earthwork volume conversion table.

Imaginary square volume, natural compactness volume, tamping body volume, loose filling volume.

Alkaline soil is soil with a soil pH greater than 7.

The alkaline reaction of the soil is reflected when the concentration of oh- ions in the soil solution exceeds the concentration of h+ ions, and the concentration of oh- ions in the solution shows the strength of the alkalinity of the soil, or the pH value.

The larger, the more alkaline it is. Soil pH value less than 7 is acidic soil, and soil pH value greater than 7 is alkaline soil.

The soil acidity and alkali in China are different, and the north of the Yangtze River is mostly neutral and slightly alkaline soil; As far as cities are concerned, there are more than 50 cities with different degrees of saline-alkali soil distribution, such as Tianjin, Dezhou, Panjin, Lianyungang and other cities.

Causes of the formation of alkaline soils:

Alkaline soil is formed by the comprehensive influence of natural conditions and soil intrinsic factors, among which arid climate and abundant calcium are the main causes. Excessive application of lime and irrigation of alkaline effluent, as well as seawater impregnation, are also responsible for the formation of some alkaline soils.

Dry and semi-arid climate zones, with atmospheric precipitation.

Alkali metals and alkaline earth metals released by weathering rocks and minerals are much lower than the amount of evaporation.

The simple salts cannot completely migrate to the earth, but accumulate in large quantities in the soil and its groundwater.

Most of these simple potassium, sodium, calcium, and magnesium salts are their carbonates or bicarbonates.

Because they are controlled by the bias pressure of the large amount of CO2 released by organisms), these salts can be hydrolyzed to produce OH ions, which allow the soil to evolve in an alkaline direction. This is the most direct and primary cause of the formation of alkaline soils.

What kind of soil is "acidic soil" for raising flowers? What soil is "alkaline soil"? The distinction is simple!

Sandy soils, clayey soils and loam soils are characterized by the following:1. Sandy soil refers to the soil with a large sand content, rough particles, fast water seepage, poor water retention performance and good aeration performance.

2. Loam refers to the soil with moderate content of clay, silt and sand particles in the composition of soil particles, and the particle size is between to. The texture is between clay and sand, and it has the advantages of clay and sand, good aeration and water permeability, water retention and thermal insulation performance, drought and waterlogging resistance, strong stress resistance, wide adaptability, long tillage period, and easy to cultivate into high-yield and stable-yield soil.

3. Clayey soil is a kind of soil, which has the characteristics of good water retention performance. Low sand content, fine particles, slow water seepage rate, good water retention performance, poor aeration performance - soil.

It depends on how long the "period" you set, as well as the precipitation, the clay soil has a strong water-holding capacity and fertilizer retention capacity, the sandy soil is the weakest, and the loam soil is in the middle. If there is little rainfall and long watering intervals, the broad beans in the sandy soil may wilt or even die, while the clay and loam soil continue to grow. If there is a lot of precipitation and frequent watering, it may cause the broad beans inside the clay to die.

Loess is a more acidic soil.

The mineral composition of loess includes detrital minerals and clay minerals, with the former accounting for more than 70%. Among the detrital minerals, it mainly refers to light minerals with less density, accounting for more than 90%, quartz is the most, feldspar is second, and there are some carbonate minerals (calcite, dolomite, etc.). The clay minerals in loess are mainly mica, kaolinite and montmorillonite.

The existence of these minerals makes the loess have the characteristics of adsorption, expansion and contraction, which affects the engineering properties of the loess. Carbonate minerals often play a cementing role, so that the loess particles often exist as agglomerates in the case of natural structure. After encountering water, the collapsibility of the loess is often enhanced due to the destruction of the aggregates cemented by soluble salts.

Therefore, some people believe that the presence of carbonates in loess is one of the reasons for the collapse of loess.

Although the detrital minerals of loess-like soil are mainly quartz and feldspar, the content of unstable minerals is low, and they are generally strongly weathered and associated with nearby bedrock.

3 5 The sub-districts are mainly distributed in Qinghai, Ningxia, Gansu and Henan provinces, covering an area of 10,000 square kilometers4km km². The upper reaches of the small watershed are generally "streams" and "palms", with relatively flat terrain and few channels. There are gullies in the middle and lower reaches.

The loess hilly and gully area is the most serious area of soil erosion in China and even in the world. Soil erosion has not only become the main problem that plagues the sustainable development of agriculture and the people's poverty alleviation and prosperity in the region, but also brings a series of ecological and environmental problems to the lower reaches of the Yellow River.

1. The advantages are different.

Loam soil has the advantages of clay and sand, good aeration and water permeability, water retention and thermal insulation performance, drought and waterlogging resistance, strong stress resistance, wide adaptability, long tillage period, easy to cultivate into high-yield and stable-yield soil, and is also an ideal agricultural soil.

Clayey soil has good water retention performance;

The sandy soil has good aeration.

2. The texture is different.

The soil particle composition of loam soil has moderate content of clay, silt and sand particles, and the particle size is between to;

Clayey soil has low sand content, fine particles, and slow water seepage.

The sandy soil has a lot of sand content, coarse particles, and fast water seepage.