Why is arid soil more easily eroded than moist soil?

Answer with Explanation:

"Arid soil" is more easily eroded than moist soil because it has a lesser amount of organic materials in it. The organic materials (earthworm, fungi, bacteria, etc.) help the soil become more stable. It also enhances biodiversity, which makes the soil more fertile because it makes it more porous. This means that it is able to facilitate both movement of air and water through the soil. The arid soil lacks in this property, thus, making it more prone to erosion.

Another reason is that the arid soil is made up of sand and silt. These do not bind the soil particles together because of lesser moisture content when compared to the moist soil that allows the soil particles to stay in-tact.  

tocharian and anatolian were belaved to become extinct during the ninth century. =)