Causes of Soil Acidification
- Precipitation is large and concentrated, leaching is strong, calcium, magnesium, potassium, and another alkaline salt loss is one of the reasons that cause soil acidification.
- The lack of traditional agricultural measures such as lime application, burning of fire excrement, and application of organic fertilizers has caused an imbalance of nutrients in cultivated soil as one of the causes of soil acidification.
- Long-term large-scale application of chemical fertilizers, especially physiological acid salt is an important cause of soil acidification.
- Chemical fertilizers have been used for many years in succession. The acid radicals remaining after the crops absorbed combine with hydrogen ions in the soil to form acids, which can lead to soil compaction, increased acidity, and cause damage to the soil structure.
- Blindly purchase and apply strong acidic fertilizers, such as organic fertilizers produced by MSG’s leftovers.
- High multiple cropping index, a large amount of fertilizer, and little rain leaching result in a decrease in soil organic matter content, a decrease in buffer capacity, and an increase in soil acidification.
The Harm of Soil Acidification
1. Root stop grow
Each crop has a suitable range of soil pH, and most plants are preferably slightly acidic to slightly alkaline. Extremely acidic soil is the main reason for tree aging. The acidification of the soil affects the growth of the crop and does not grow to a certain extent. The acidification of the soil is also extremely detrimental to the growth of the banana, which causes the leaves of the banana to dry out prematurely and is extremely unfavorable to the protection of the banana.
2. Leaching of protein isolate in acidic soils is one of the essential reasons for the decline of soil fertility
After the acidification of the soil, the effectiveness of the fertilizer is affected, phosphorus is still lacking after the application of phosphorus, and potassium is still lacking after the use of potassium. At pH 6-8, the content of available nitrogen in the soil is the highest. When the pH is less than 6.5, the phosphorus in the soil becomes iron phosphate aluminum and solidifies. When the pH value is less than 6.0, the content of available potassium, calcium, and magnesium in the soil is drastically reduced. Soil acidification affects not only the availability of a large number of elements but also affects the availability of trace elements. Boron is in the pH range of 4.7 to 6.7, and molybdenum is in the pH range of 4 to 8 with a decrease in pH, and the effectiveness is reduced.
Soil Response (ph) Discomfort: Soil reactions strongly affect the solubility of nutrient elements, i.e., effectiveness. Some parts are easily dissolved under acidic conditions, have high efficiency, high effectiveness, and the solubility-effectiveness of the reaction tends to be neutral or alkaline. In contrast, some of the other elements are more effective under alkaline conditions and less effective under acidic conditions.
Trace elements are particularly closely related to the reaction. For example, the solubility of iron, boron, zinc, and copper decreases with pH (less than pH 4.5), the effectiveness increases rapidly, and the efficiency decreases when the pH is close to neutral or alkaline. Molybdenum is the opposite, effect Increase with pH increase.
A large number of elements are generally unresponsive to pH, but phosphorus is the exception. Phosphorus has a suitable pH range that is extremely narrow. Strictly speaking, it is only about pH 6.5 if pH<6.5, and the iron and aluminum in the soil are fixed. The lower pH, the more excellent the solubility of iron and aluminum, the higher the amount of immobilization. If pH>6.5, phosphorus is combined with the calcium in the soil, and the effectiveness is also reduced. However, the solubility of calcium phosphate is more significant than that of iron phosphate and aluminum phosphate, so the availability of phosphorus in alkaline soils is usually higher than that of acid soils.
3. Soil acidification will affect the life activities of soil microorganisms
Acidification of soil will reduce the number of beneficial organisms in the soil, inhibit the growth and activity of beneficial microorganisms, and thus affect the decomposition of soil organic matter and the circulation of C, N, P, and S in soil.
For some species of harmful microorganisms that like to work in acidic soils, they are beneficial to survive, resulting in the growth of pathogens, increased rhizospheric diseases, and difficult to control, such as clubroot disease of cruciferous and bacterial wilt, yellow vegetables, Increased wilt. The ideal living environment for Banana Panama disease is acidic soil.
4. Soil acidification promotes the release and activation of toxic elements and increases cadmium contamination
After the soil is acidified, aluminum ions and other substances in the soil poison the plant roots and cause death.
Soil acidification aggravates the occurrence of manganese poisoning. When the apple germinates in spring, some of them cannot germinate or sprout after germination. Do not draw new ones, form a small old tree, one branch is fine, the middle is thick, like Kashin-Beck disease, some twigs inexplicably died during the growth period. Some branches of the trunk shed water, some trunks were uneven or tumors, peeling off the epidermis with a knife, many small black spots were found, and some fruit farmers treated it as a ringworm disease. It has no effect after years of treatment; some fruit trees have a very good root system, which is a small fruit and poor coloring. These phenomena are caused by manganese poisoning in the tree. Increase the leaching and dissolution of aluminum ions and toxic metal ions such as manganese, chromium, and cadmium, and contaminate the soil and water environment. More seriously, it may also harm the health of humans and animals through the food chain.