What is inside horse manure that helps plants grow?

Horse manure is rich in essential nutrients that promote plant growth, including nitrogen, phosphorus, and potassium. It also contains beneficial microorganisms that enhance soil health and improve nutrient availability. Additionally, its organic matter helps improve soil structure and moisture retention, creating a better environment for plant roots to thrive. However, it's important to compost horse manure before use to reduce pathogens and weed seeds.