Wind erodibility of soils at Fort Irwin, California (Mojave Desert), USA, before and after trampling disturbance: implications for land management

Abstract

Recently disturbed and 'control' (i.e. less recently disturbed) soils in the Mojave Desert were compared for their vulnerability to wind erosion, using a wind tunnel, before and after being experimentally trampled. Before trampling, control sites had greater cyanobacterial biomass, soil surface stability, threshold friction velocities (TFV; i.e. the wind speed required to move soil particles), and sediment yield than sites that had been more recently disturbed by military manoeuvres. After trampling, all sites showed a large drop in TFVs and a concomitant increase in sediment yield. Simple correlation analyses showed that the decline in TFVs and the rise in sediment yield were significantly related to cyanobacterial biomass (as indicated by soil chlorophyll a). However, chlorophyll a amounts were very low compared to chlorophyll a amounts found at cooler desert sites, where chlorophyll a is often the most important factor in determining TFV and sediment yield. Multiple regression analyses showed that other factors at Fort Irwin were more important than cyanobacterial biomass in determining the overall site susceptibility to wind erosion. These factors included soil texture (especially the fine, medium and coarse sand fractions), rock cover, and the inherent stability of the soil (as indicated by subsurface soil stability tests). Thus, our results indicate that there is a threshold of biomass below which cyanobacterial crusts are not the dominant factor in soil vulnerability to wind erosion. Most undisturbed soil surfaces in the Mojave Desert region produce very little sediment, but even moderate disturbance increases soil loss from these sites. Because current weathering rates and dust inputs are very low, soil formation rates are low as well. Therefore, soil loss in this region is likely to have long-term effects. Published in 2006 by John Wiley & Sons, Ltd.

Effect of vegetation and its succession on water repellency in sandy soils

“…Biocrusts can cause local water redistribution by increasing surface run‐off (Cantón, Domingo, Solé‐Benet, & Puigdefábregas, ; Keck, Felde, Drahorad, & Felix‐Henningsen, ) and protect the soil against water and wind erosion (Belnap, Phillips, Herrick, & Johansen, ; Kidron, ; Rodríguez‐Caballero, Cantón, Chamizo, Lázaro, & Escudero, ). Bacteria can block smaller pores and reduce flow of water through soil due to adhesive or surface active compounds that can alter surface tension and affect water retention (Hallett, Karim, Bengough, & Otten, ).…”

Dynamic cyanobacterial response to hydration and dehydration in a desert biological soil crust

“…BSCs can be considered ecosystem pioneers, being the first primary producers, fixing carbon and increasing soil organic matter that reduces wind and water erosion (Belnap and Gillette, 1998; Kidron and Yair, 2001; Belnap et al , 2007). Their colonization of these desert soils may facilitate the subsequent growth of vascular plants by providing and recycling critical nutrients (Mayland and McIntosh, 1966) and have a major role in the nitrogen balance of these ecosystems (Strauss et al , 2011).…”

Microbial Nursery Production of High-Quality Biological Soil Crust Biomass for Restoration of Degraded Dryland Soils

“…Biocrusts are complex, topsoil microbial assemblages that develop on the primary production of soil cyanobacteria, microalgae (sometimes in algal symbioses), or mosses and that support a large diversity of heterotrophic bacteria (9), archaea (10), and fungi (11). Considered to be a "mantle of fertility" in arid lands (12), biocrusts provide essential goods and services; they stabilize soils and thus reduce rates of wind erosion and dust particle production (13), can influence soil temperature (14,15), contribute significantly to soil C and N inputs into the ecosystem (16), increase the lixiviation of micronutrients (17), control soil hydrological dynamics (18), and are thought to provide good conditions for plant germination and establishment (19).…”