Background and AimsThe invasive annual grass, Bromus tectorum L. (cheatgrass), is present across the western United States. Invasion is often attributed to cheatgrass' high productivity, which contributes to fire frequency and litter buildup. Litter may create favorable microsites by altering soil-water storage, which may differ according to soil properties (e.g. soil carbon (C)).MethodsWe investigated whether litter buildup and differences in soil C facilitated or inhibited B. tectorum by comparing the effects of B. tectorum litter on soil moisture, and B. tectorum growth using two soil orders common in semiarid rangelands-Mollisols and Aridisols.ResultsBromus tectorum seed emergence and growth consistently increased relative to litter-free controls with increasing litter depths from 1-7 cm in the Aridisol but not the Mollisol. Across litter depths, there was a two-fold difference between B. tectorum biomass grown in Aridisols versus Mollisols. The Aridisol had lower soil C and less plant available water than the Mollisol in the absence of litter. However, with increasing litter depth, water availability increased to a greater degree in the Aridisol than the Mollisol, resulting in similar amounts of plant available water at deep litter depths. Thus, water availability was increased by litter in the Aridisol and soil C in the Mollisol.ConclusionLitter reduction may be an effective way to mitigate B. tectorum growth to reduce water availability in Aridisols. However, in Mollisols, greater nutrient content and higher water availability provided by soil C make litter reduction a less effective method for controlling B. tectorum. By understanding the effects of litter and soil on water availability in drylands, managers can target appropriate treatments to control B. tectorum.