This question and answer are part of our Ask CSU Extension Anything (About Native Plants) series. We appreciate CSU Extension for answering these questions to expand our community’s knowledge of native plant landscaping. Send us your questions to the Ask CSU email account.
In a drought with significant wind erosion, are there any strategies for introducing drought tolerant native plants to barren slopes and flat areas to prevent further erosion and begin to rebuild the soil?
Yes! The first step is to cover the soil to protect it against further wind erosion. In agricultural systems, crop residues and/or manure are commonly used for this purpose—though some materials will need to be anchored to prevent them from blowing away! This is particularly true of straw.
Mulch is another good option—particularly coarse wood chip mulch (not bark), with pieces large enough to resist being blown away. Avoid using shredded cedar bark (“gorilla hair” mulches) because they mat into a waterproof layer, preventing precipitation from infiltrating.
Gravel (with rocks of ½” diameter or less) would also be acceptable mulch, and has been shown to improve infiltration of precipitation, so when we do get moisture in the form of snow or a summer thunderstorm, more of it will end up in the soil profile.
If soil test results indicate organic matter below 3%, consider incorporating compost into the soil before covering with the mulch. You don’t need to pulverize the soil to mix it; to help fight erosion, leaving the native soil in large chunks is preferable. For sites that require complete remediation and have no plants, you can spread the compost on the surface, then “scoop and dump” in order to mix the compost into the soil profile to a depth of 18” (this is usually best accomplished with equipment like a backhoe or mini-excavator). Then plant plants or seeds—if you can water them until establishment you will have better results.
For soils with adequate organic matter, you can plant or seed your preferred vegetation. Apply a thick layer (4”) of mulch immediately after planting if using plants. If seeding, a thinner mulch layer will help hold the soil in place while still allowing for germination—gravel mulch is a great option in this situation.
Be sure to include plants that develop quickly in your planting mix. Native annuals or even sterile cover-crops can help stabilize the soil and provide additional residue to build the soil and trap moisture over time. Shrubs or trees can be used to help further protect the area from wind. Which plants you choose will be informed by your soil conditions, but be sure to choose drought-tolerant natives!
This CSU publication discusses the physics of wind erosion of soils and includes resources for protecting and conserving the soil. While it is aimed at agricultural producers, the information is still applicable for establishing permanent vegetation on disturbed sites.
Answer developed by: John Murgel (Extension County Specialist, Horticulture and Natural Resources, Douglas County) Colorado State University Extension.
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