The large-scale development of cow dung organic fertilizer production line can be carried out from the following aspects:

1. Optimize fermentation process: adopt advanced fermentation technology, such as adding composite microbial agents for two fermentations to improve fermentation efficiency and product quality. Introduce automatic control system to achieve precise operation of equipment and improve production efficiency.

2. Policy support: Actively apply for government subsidies for organic fertilizer production, such as organic fertilizer equipment purchase subsidies, tax incentives, etc. Pay attention to government-supported livestock and poultry manure resource utilization projects, and strive for project funding support.

3. Market promotion: Strengthen brand building, establish a good brand image and enhance brand influence by improving product quality and service level. Use e-commerce platforms, professional exhibitions and other channels to broaden sales channels and increase product market coverage.

4. Cooperation and alliance: Establish long-term cooperative relations with universities and scientific research institutions, jointly carry out technology research and development, and improve the company's technological innovation capabilities. Establish long-term cooperative relations with upstream raw material suppliers and downstream growers to form a complete industrial chain.

5. Demonstration and training: Select some typical cases and establish demonstration sites in rural areas to demonstrate the effects and benefits of the project and attract more people to participate and invest. Organize professional training teams to provide technical training to farmers to improve their understanding and use of organic fertilizer equipment.

Through the above measures, the large-scale development of cow dung organic fertilizer production lines can be effectively promoted, production efficiency can be improved, production costs can be reduced, market competitiveness can be enhanced, and the sustainable development of agriculture can be promoted.