Seaweed fertilizer and sheep manure each have their own advantages and disadvantages, but seaweed fertilizer is generally considered to be more beneficial to crop growth and immunity. The specific reasons are as follows:

1. Seaweed fertilizer is rich in Alginic acid, mannitol, betaine and other substances that are beneficial to plant growth and health can significantly improve the vitality and immunity of crops, inhibit the growth of pathogens, and have obvious prevention and control effects on viruses.

2. The alginic acid in seaweed fertilizer can react with iron, aluminum and other ions in the soil to make the soil soft, improve soil hardening, enhance the stress resistance of crops, and reduce drought and waterlogging. Adversities such as waterlogging, low temperature, and salinity can harm crops.

3. The alginic acid in seaweed fertilizer can increase the content of soluble phosphorus in the soil, promote the release of insoluble phosphorus in the soil, and at the same time improve the utilization rate of phosphorus in the soil, providing more phosphorus elements for crops. .

4. Seaweed fertilizer contains natural growth regulators, which can promote the growth and development of crops, improve the quality of agricultural products, and increase crop yields.

Although sheep manure is also a high-quality organic fertilizer, its fertilizer effect is slow and needs to be decomposed and fermented to exert its full fertilizer effect. In addition, sheep manure also contains a large amount of nitrogen, which can easily cause root burn if used improperly.

To sum up, seaweed fertilizer has greater advantages in improving the vitality and immunity of crops, inhibiting the growth of pathogens, improving soil quality, and increasing phosphorus utilization. Therefore, it is generally considered to be better than sheep manure. More beneficial to crop growth and immunity. However, the specific fertilizer to use needs to be comprehensively considered based on factors such as crop type, growth stage, soil conditions, etc.