Long-term use of organic fertilizers generally does not lead to soil salinization, but has a positive effect on improving saline-alkali land for the following reasons:

1. Reduce soil salt content

Adsorption: Organic fertilizers are rich in organic matter and have a high cation exchange capacity. They can adsorb salt ions such as sodium ions in the soil, reduce the concentration of exchangeable salt ions in the soil, and thus reduce the soil salt content.

Leaching effect: The application of organic fertilizers can improve soil structure, increase soil porosity and permeability. Good soil structure can also reduce water evaporation and reduce the risk of salt accumulation in the soil surface due to evaporation.

2. Regulate soil pH

Neutralize alkalinity: Saline-alkali soils are usually alkaline with a high pH value. Substances such as organic acids and humic acid in organic fertilizers can react with alkaline substances in the soil to reduce soil pH and alleviate the degree of soil alkalinization.

Stabilize pH: Long-term application of organic fertilizers can make soil pH more stable. Organic matter can buffer the changes in soil pH and avoid drastic fluctuations in soil pH caused by factors such as fertilization and irrigation. This helps maintain the appropriate pH range of the soil and create a good soil environment for crop growth.

3. Improve soil structure

Promote aggregate formation: Organic matter in organic fertilizer is an important binder for the formation of soil aggregates. Long-term application of organic fertilizer can promote the formation and stability of soil aggregates and improve soil structure.

Enhance soil fertility: Organic fertilizer contains rich nutrients such as nitrogen, phosphorus, potassium, calcium, magnesium, etc., as well as various trace elements. Long-term application of organic fertilizer can improve soil fertility and provide sufficient nutrients for crop growth.

In summary, long-term use of organic fertilizer generally does not lead to soil salinization, but helps to improve saline-alkali land, improve soil quality, and promote sustainable agricultural development.