What is the ruling on the impurity of a dog if it falls on sand, and is it sufficient to throw earth over it, and how is the impurity removed by pouring water seven times using a hose instead of a pitcher, and does leaving it under the sun purify it?

The vomit and urine of a dog are impure by consensus.

Shafi'is: To purify earthen ground from dog impurity, it must be washed seven times with water only, without any foreign soil. A single washing is considered to be the drenching of the spot with water. Hanbalis: Impurity on the ground is purified by the removal of its substance or by pouring a large amount of water over it, without requiring a specific number of washes. If the impurity is difficult to remove, the hardship is waived. Hanafis: If the ground becomes impure with urine, water is poured over it, it is rubbed, and then dried three times. Alternatively, a large amount of water is poured over it until the impurity and its trace disappear, and it is then left to dry.

Purity of Ground by Drying: Hanafis: The ground becomes pure by drying and the removal of the impurity's trace (color, smell, and taste). There is no difference whether it dries by sun, wind, or fire. Hanbalis: The madhhab does not hold that the ground becomes pure by drying, or by sun or wind, though some of them agreed with the Hanafis. Shafi'is: The old opinion holds that it becomes pure by drying, but the new, and more correct, opinion does not hold that it becomes pure.