Many practitioners have found that including a mulch layer (often of native hay or mesquite chips) over seeded areas can facilitate establishment of desired species and reduce weed encroachment. When acquiring mulch, ensure that it is weed free by purchasing it from a certified producer. Most organic mulch types enhance soil nitrogen which disproportionately benefits invasives and should be avoided in arid systems. Gravel or rock mulch, thinly applied with visible soil in between the piece of aggregate can provide benefits expected from organic mulches, such as moisture retainment [1] without nitrogen addition into the system [2]. Woodchips have been found to limit the growth of native species, but may be appropriate after wildfire [3]. In semi-arid regions that have biological soil crust, thick mulch can limit the recovery of biological soil crust organisms.
Resources
- Water-Wise Landscaping: Mulch | USU
- Using Mulches in Utah Landscapes and Gardens
- Mulching is Important for Tree Health | Forestry | Extension | USU
- Mulch, Bark, & Soil Requirements - Millcreek Garden
- Comparing the Ignitability of Mulch Materials for a Firewise Landscape
- Vertical Mulching: A story of “Planting Dead Branches” to Restore Desert Habitat - Amargosa Conservancy
- Assessing Minimal-Input Restoration Strategies for Desert Soil and Vegetation Restoration
- Mulch more so than compost improves soil health to reestablish vegetation in a semiarid rangeland
References
[1] Homburg JA, Sandor JA. Anthropogenic effects on soil quality of ancient agricultural systems of the American Southwest. CATENA. 2011 [accessed 2022 Dec 23];85(2):144–154. (Soils, Sediments, and Geoarchaeology). https://www.sciencedirect.com/science/article/pii/S0341816210001256. doi:10.1016/j.catena.2010.08.005
[2] Dreesen D. Seeding native grasses in the arid Southwest. USDA-NRCS Plant Materials Center, Los Lunas (NM): NCRS New Mexico Website.; 2009. p. 6. ID # 8352. https://www.nrcs.usda.gov/plantmaterials/nmpmcmt8352.pdf
[3] Grover H. Mitigating Postfire Runoff and Erosion in the Southwest using Hillslope and Channel Treatments. ERI Working Paper No. 44. Ecological Restoration Institute, Northern Arizona University; 2021. 11 p. https://aftertheflames.com/wp-content/uploads/2021/02/44_Working-Paper_Mitigating-Postfire-Erosion_WEB.pdf