The patchy distribution of vegetation within semi-arid shrublands is usually mirrored in nutrient distributions in soil beneath perennial shrubs (macrophytic patches) and inter-shrub areas (microphytic patches). We compared soil C and N pools in two semi-arid shrublands, in: 1) the Negev Desert of Israel (Lehavim), which receives >90% of annual rainfall during winter, and 2) the Chihuahuan Desert, Arizona, USA (FHMR) with a bimodal (summer – winter) rainfall pattern. We found more distinct differences in soil properties between patch types at Lehavim than at FHMR. Soil at Lehavim had much higher soil organic C and N, amino acids and sugars, asparaginase activity, and plant-available N compared to FHMR. For example, soil organic C (0-5 cm) in macrophytic patches was 39 g kg-1 at Lehavim and 13 g kg-1 at FHMR. We conclude that differences between precipitation pattern at the sites impact mineralization rates of organic inputs in these semiarid ecosystems and account for larger C and N pools in Lehavim soils. Greater differences in soil properties between patch types at Lehavim than at FHMR are due to the increasing importance of physical processes of resource dispersion at the more humid site in Arizona.
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