News Release

Oct. 15, 2018 – Have you noticed wavy bands of soil along roads or paths? The Soil Science Society of America (SSSA) Oct. 15 Soils Matter blog explains these horizontal soil waves and the unusual way they form.

Lamellae are thin, wavy plates of soil. They are created when clay particles within the soil bond together. This typically happens when water infiltrates down through the soil, picking up clay particles on its way. If this slurry hits a drier layer of soil, the clay is deposited in a horizontal pattern and voila! Lamella!

But this happens on a timescale beyond a human life. “Soils form and change (generally) on geologic time scales,” says Mike Badzmierowski, a doctoral student at Virginia Tech. “Lamellae have been described in soils dating less than one thousand years old, suggesting that they can form in hundreds of years.” 

That’s quick in geological terms. Lamellae also develop in an unexpected pattern because of how water moves. “The oldest lamella is the band closest to the soil surface while the lowest lamella is the youngest,” Badzmierowski notes. “Since this process is not uniform, lamellae are wavy and can develop branches.”

What else do we know about soils with lamellae? They hold water well and generally improve sandy soils from an agricultural standpoint. However, “these soils can be poorly suited for septic tank absorption fields and sewage lagoons,” Badzmierowski says. “That’s because although the sandy interlamellae (layers between the lamellae) readily absorbs water, it doesn’t adequately filter the effluent. The poor filtering can result in the pollution of groundwater supplies.”

To read the entire blog post, visit https://wp.me/p3Rg6r-qq.

Follow SSSA on Facebook at https://www.facebook.com/SSSA.soils, Twitter at SSSA_Soils. SSSA has soils information on www.soils.org/discover-soils, for teachers at www.soils4teachers.org, and for students through 12th grade, www.soils4kids.org.