Posts Tagged ‘hardpan’

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Strangeness in the desert soil: Caliche

May 4, 2008

Here’s one way to encounter caliche. Some friends pulled over one night in the New Mexico desert and camped in their truck. Happily for the desert, there was rain in the night. Unhappily for the humans, the next morning they found themselves surrounded by a huge pond of extremely slippery ankle-deep goo. Only after a long dirty struggle were they able to push their truck back onto the road. Caliche is what allowed a mudbath to form in the middle of the desert.

Another way to discover caliche is to dig a hole almost anywhere in the desert. Soon, inches or feet deep, you’ll hit a layer of what seems to be cement, even in places where you know there’s never been any construction.

What you’ve found is caliche, a white layer of soil, rich in calcium carbonate, clay, and other minerals that have been driven down into the ground by the hard infrequent desert rains, until the minerals form an often impervious layer of soil, also known as hardpan.

Wikipedia can tell you more.

When rain falls on an area with dense caliche, rather than sinking into the soil, the water runs off, if it can find a channel, sometimes causing the surprising desert flash floods, because so little water is absorbed into the ground. Or it puddles up, creating a sea of mud.

Digging a simple hole can require a pickaxe. Since the calcium carbonate can be alkaline enough to harm plant roots, planting in an area with caliche means that you may have to add conditioners as well as┬ánutrients to the soil– and make sure there is drainage, even if that means digging a drainage hole through the caliche.

The Arizona Master Gardener, a great source of information, gives details of how to deal with it.