Soil buffering in soil chemistry, the causes of soil buffering

One of the chemical properties of the soil. Refers to the ability of the soil to resist changes in pH, or a property of the soil to resist changes in the concentration of ions in a soil solution. Resulting from the adsorption of ions by clay and humus in soil.

A certain amount of carbonate and phosphate have a similar effect. Soil buffering can transform the ions in the soil solution into an adsorbed state that is difficult to dissociate, or change the composition and activity of ions in the solution. The complexation of organic matter and the obligate adsorption of oxides are important factors to control the concentration of heavy metal ions in soil solutions.

The buffering capacity of the soil generally depends on the amount of cation exchange. Soil buffering capacity can be determined using the pH titration curve method (Figure 5). It can be seen from the figure that the buffering capacity of black soil colloids is greater than that of loess and red soil colloids.

In addition, the slope of the Qi curve (the ratio of the activity of cations to other cations in the solution i, plotting the change value of the exchangeable cation q) reflects the buffer capacity of the soil for cations. The slope at any point on the adsorption isotherm (Dy DC, Y is the adsorption capacity, C is the equilibrium concentration) also reflects the buffer capacity of the soil at a given value of ions. In general, the buffering capacity of soil solutions is related to the content of humus and clay, because of the high cation exchange capacity of both.

Soil buffering has a stabilizing effect on the increase of H+ concentration in soil solution caused by microorganisms, respiration of plant roots, decomposition of organic matter and application of chemical fertilizers, which is related to ensuring the normal growth of plants.

Soil buffering.

The ability of a soil solution to resist changes in pH is called soil buffering.

The reasons for soil buffering are as follows:

Soil buffering noun detoxification refers to the ability of soil to moderate pH changes when acid or alkali is added.

Soil bufferingWhen a small amount of acidic or alkaline substances are added to the soil, the soil has the ability to moderate the change of its acid-base reaction. The buffering performance of soil is mainly achieved through the ion exchange of soil colloids, the dissociation of strong bases and weak salts, etc., of course, this buffering performance is limited for a specific soil.

Soil buffering performance is mainly achieved through the ion exchange of soil colloids, the dissociation of strong alkalis and weak salts, etc., so the level of soil buffering performance depends on the type and total amount of soil colloids, and the content of carbonate, bicarbonate, silicate, phosphate and biphosphate in the soil.

The soil has a certain ability to resist the change of H+ or OH- concentration in the soil solution, which is called the buffering property of the soil. Because the soil has a buffering property, it helps to moderate the changes in soil acidity and alkalinity, and creates a relatively stable living environment for plant growth and microbial activity.

The soil buffering effect is due to the absorption of many substitutionary cations by the soil colloid, such as Ca2+, Mg2+, Na+, etc., which can buffer acids, and H+, Al3+ can buffer alkalis. The magnitude of soil buffering is related to the amount of soil substitution, which increases with the increase of the amount of early suffocation.

Soil buffering properties include the buffering properties of soil solutions and soil colloids. Socks are in the air.

1. Buffering performance of soil solution: buffering effect of soil solution: soil solution contains weak acids and salts such as carbonic acid, silicic acid, phosphoric acid, humic acid and other organic acids, which constitute a good buffer system and have a buffering effect on acid and alkali.

2. Buffering performance of soil colloid: The buffering effect of soil colloid: soil colloidal adsorption has various cations, of which salt-based ions and hydrogen ions can buffer acids and alkalis respectively.

The greater the amount of soil colloids and the amount of salt base substitution, the stronger the buffering performance of the soil. Therefore, the mixing of sand with clay and the application of various organic fertilizers are effective measures to improve the buffering performance of soil. Under the condition of equal substitution, the higher the saturation of the salt base, the greater the buffering capacity of the soil to acid. On the contrary, the lower the saturation of the salt base, the greater the buffer capacity of the soil to alkali.

Summary. Soil buffering has a certain effect on soil temperature. Soil buffering refers to the ability of the soil to respond to changes in the external environment.

When the soil temperature changes, the soil with better buffering can slow down the speed of this change to a certain extent, thereby reducing the amplitude of soil temperature fluctuation. On the contrary, if the soil buffering is poor, it is often difficult for the soil to quickly adapt to changes in the external environment, and the soil temperature will be more likely to fluctuate, resulting in large fluctuations in root temperature and affecting plant growth and development. Generally speaking, soils with high water content, rich organic matter content, and deep soil layers have better buffering properties and can reduce the amplitude of soil temperature fluctuations.

At the same time, mulch and vegetation can also play a certain role in heat preservation and moisturization, and enhance the cushioning of the soil.

Soil buffering has a certain effect on soil temperature. Soil buffering refers to the ability of the soil to respond to changes in the external environment. When the soil temperature changes, the soil with good buffer moderation can slow down the speed of this change to a certain extent, thereby reducing the amplitude of soil temperature fluctuation.

On the contrary, if the soil buffering is poor, it is often difficult for the soil to quickly adapt to the changes in the external environment, and the soil temperature will be more likely to fluctuate, which will cause the root temperature to fluctuate greatly, which will affect the growth and development of plants. Generally speaking, soils with high water content, rich organic matter content, and deep soil layers have better buffering properties and can reduce the amplitude of soil temperature fluctuations. At the same time, mulch and vegetation can also play a certain role in heat preservation and moisturization, and enhance the cushioning of the soil.

The pH value of the soil changes frequently, is the buffering just a decrease in the pH value?

Soil buffering refers not only to the ability to respond to changes in pH, but also to other environmental factors such as moisture, temperature, etc. The pH value of soil is an indicator that reflects the degree of soil acidity and alkalinity, while the buffering capacity of soil refers to the ability of soil to respond to and regulate changes in the external environment. Soils with better buffering can slow down the rate of environmental change, thereby reducing the impact of environmental change on the ecosystem.

For the pH value, the soil with good buffering can slow down or reduce the influence of external factors (such as acid rain and fertilization) on the pH value, so that the pH value changes less, and can provide more stable habitat conditions from the early stage, which is conducive to the growth and development of plants. Therefore, the buffering capacity of the soil is not only to reduce the magnitude of pH changes, but also to respond to other environmental factors.

Soil buffering refers to the ability of the soil to resist drastic changes in acidity and alkalinity caused by foreign substances. This performance of the soil can keep the pH of the soil within a certain range, and avoid significant changes in soil pH caused by fertilization, root respiration, microbial activity, and organic matter decomposition.

1. The mechanism of soil buffering.

One is the buffering effect of exchangeable cations. When acids and alkalis enter the soil, they can be exchanged with exchangeable cations in the soil to produce water and neutral salts. The second is the buffering effect of weak acids and their salts.

The carbonic acid, phosphoric acid, silicic acid, humic acid and its salts that exist in large quantities in the soil constitute a good buffer system, which can play the role of buffering acid or alkali. The third is the buffering effect of amphoteric substances. Proteins, amino acids, and humic acids in the soil are amphoteric substances, which can neutralize both acids and alkalis, so they have a certain buffering effect.

2. Factors affecting soil buffering.

The main ones are: first, soil texture. The heavier the soil texture, the stronger the buffering performance of the soil. On the contrary, the more sandy the texture, the weaker the cushioning performance.

The second is soil organic matter. Because the specific surface of organic colloids and the negative electricity carried by them are much greater than those of inorganic colloids, and some of the organic matter is a high imitation of amphoteric substances, the stronger the buffering performance of the soil with high organic matter content. Conversely, the weaker. The third is the type of soil glue and rot.

The buffering properties of organic colloids are greater than those of inorganic colloids, and in inorganic colloids, the order of buffering properties is: montmorillonite, illite, kaolinite, iron-aluminum oxides and their hydrous oxides.

Soils are usually loose and compressible, and when subjected to impact, there is a gradual process of being compacted and absorbing the impact energy, so it has cushioning properties.

The buffering nature of the soil has a narrow sense.

and broadly defined. Soil buffering in the narrow sense refers to the ability of the soil to resist the change of pH value in acids and alkalis.

Soil buffering in a broad sense refers to the ability of soil to resist environmental factors and change them, including the buffering of soil nutrients, environmental pollutants, and redox substances.

The main mechanism of buffering acid and base is the exchangeable adsorption of soil colloids, and the mechanism of buffering soil nutrients and pollutants is also the exchangeable adsorption and obligate adsorption of soil colloids.

The mechanism of buffering redox is mainly that there are many redox systems in the soil, the most important of which is the decomposition and accumulation of organic matter.

I hope it helps you understand...

Buffering effect of soil

Soil du has zhi a certain resistance to soil solution.

The ability of DAOH+ or OH+ concentrations to change back is called the slow flushing performance of the soil. Because the soil has a buffering property, it helps to moderate the changes in soil acidity and alkalinity, and creates a relatively stable living environment for plant growth and microbial activity. The soil buffering effect is due to the absorption of many substitutionary cations by the soil colloid, such as Ca2+, Mg2+, Na+, etc., which can buffer acids, and H+, Al3+ can buffer alkalis.

The magnitude of soil buffering is related to the amount of soil substitution, and it increases with the increase of substitution.

The soil itself is a loose or dense mixture, which has a certain deformation under the impact of external forces, and can absorb part of the momentum.