Vietnam is a country with a large area of acid sulfate soil (sour soil). So what is acid sulfate soil? How does acid sulfate contamination occur? What are the effective measures to improve acid sulfate soil?
” Acid sulfate soil is soil containing a lot of sulfate radicals (SO42-), a low pH of only 2-3 and a very high amount of toxic substances Al3+, Fe2+, SO42. Therefore, the exchange and buffering capacity of the soil environment is broken, the soil loses its ability to self-clean (regenerate). These things cause soil pollution, and plants and microorganisms will be affected in a series of ways.”

Sea levels rise and flood the land, sulfate salts in seawater mix with soil sediments containing iron oxides and organic matter.
- CAUSES AND PROCESS OF SOIL CONTAMINATION
In addition to the above factors that cause the formation of acid sulfate soil (salty and acidic soil). There are also cases where acid sulfate water from other places gradually encroaches on the soil’s ecological environment. Acid sulfate soil is common in tropical and subtropical climates.
Causes of acid sulfate soil:
- Mainly in areas of marshy terrain, mangrove forests, and river mouths with low-lying terrain and poor drainage.
- Formed by alluvial deposits combined with acid sulfate materials (organisms containing a lot of sulfur) and acid sulfate salts.
- Due to rising sea levels and flooding the land, sulfate salts in seawater mix with soil sediments containing iron oxides and organic matter.
- When people use fertilizer products containing a lot of sulfur and do not improve for a long time, the soil is exposed and oxidized, leading to acid sulfate contamination

Salt acid soil limits the ability of plants to exchange nutrients, causing poor growth and development, resulting in low yields.
- THE SEVERITY OF ALUM SOIL FOR CROPS
Soil cannot self-repair if it lacks or loses nutrients, plants will not be able to grow. Alkaline soil has a negative impact on the process of exchanging and absorbing nutrients in the soil.
Acid sulfate soil limits the ability of plants to exchange nutrients. Plants often grow and develop poorly, bringing low yields in this environment.
Some common phenomena in plants: dead shoots, dead seedlings (rice plants), yellow leaves, slow flowering, etc.
- EFFECTIVE MEASURES TO IMPROVE ACID SOIL FOR FARMERS
Irrigation measures (souring and washing salt): To grow crops conveniently on acid sulfate soil, irrigation measures are the top priority. Building a system of ditches, irrigation canals, and parallel drainage canals to wash acid sulfate from the soil will be effective.
Liming: Another effective solution to improve acid sulfate soil is liming. The main purpose is to provide calcium to help neutralize acidity, reduce the toxicity of free iron and aluminum oxide content.
Increase organic fertilizers, manure, micronutrients, nitrogen fertilizers, phosphate fertilizers, etc.: Helps increase humus to help the soil retain nutrients well, increase fertility. Improve pH, create conditions for microorganisms to develop. Fertilize in balance, adjust appropriately between N, P, K to suit the plants. Avoid using fertilizers containing sulfur such as nitrogen sulfate, potassium fertilizer, etc.
Use organic carbon: Is a product from Japan (Nema2 brand), used for soil improvement, neutralization, lowering acidity, and increasing fertility. Use by mixing with water and spraying directly onto the surface of the soil, organic carbon particles easily penetrate deep into the soil, activate and treat pesticide residues and chemicals in the soil. Creating a favorable environment for microorganisms to develop helps the soil to be loose, thereby helping plants to grow well, absorb nutrients in the soil to the maximum and increase productivity.
Cultivation measures: For cultivation measures, the first important thing to pay attention to is the soil preparation process. Depending on the type of crop, there are measures: making rows of plants, deep plowing, drying, etc. Then, thanks to rainwater or irrigation water, it will help wash away the acidity of the soil, limiting pests and diseases.

JAPAN VIETNAM SMART FUTURE JOINT STOCK COMPANY
JAPAN VIETNAM SMART FUTURE JOINT STOCK COMPANY (JVSF)
Website: www.jvsf.vn – Email: info@jvsf.vn
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