The key differences between surface and sprinkler irrigation systems lie in their water application methods. Surface irrigation systems involve flooding the soil surface with water, which can lead to runoff and evaporation. Sprinkler irrigation systems, on the other hand, involve spraying water over the soil surface, which can lead to evaporation and drift. Surface irrigation systems are often used for crops that require flooding, such as rice or cranberries, while sprinkler irrigation systems are better suited for crops that require more targeted water application, such as lawns or gardens.