Eli5 How can dirt become hydrophobic?

Question

I saw a video about some plants that had become dehydrated because the soil had turned hydrophobic, and was wondering how and why it did that?

In: 11

Answer 1

Usually caused by a buildup of waxy compounds in the soil. Some plants like eucalyptus are quite waxy, and as they decompose the wax remains and builds up. It’s most common in sandy soils – the larger particle size (as compared to silt) means they have a smaller surface area, and are more likely to be fully coated by the wax.