The researchers studied the soil water properties in the Tarim Desert Highway Shelterbelt using saline water drip-irrigation. They measured soil water characteristics at different depths and found that the soil's ability to retain water varied across depths. The upper layers of soil had more readily available water compared to deeper layers. The study showed that the soil's water-holding capacity decreased with depth, with the upper layers having the highest moisture content. The researchers also identified the optimal soil moisture content for plant growth.