Central Nevada riparian areas: Physical and chemical properties of meadow soils

Despite the importance of soil characteristics for classifying riparian eco system types and evaluating ecosystem or range condition, little informatio n exists on western riparian area soils or the factors that influence them. We examined the effects of drainage basin geology and water table depth on soil morphology and soil physical and chemical properties of meadow sites in central Nevada. We described and analyzed the soils of meadows that occu rred in 4 drainages with different geology and that exhibited high water ta bles (0 to -20 cm from the surface), intermediate water tables (-30 to -50 cm), and low water tables (-60 to -80 cm). Pedons of high water tables site s had thick O-e horizons, dark, fine-textured A horizons, no B horizons, an d lower C horizons high in coarse fragments. In contrast, pedons of low wat er tables sites were characterized by deep, dark and organic-rich A horizon s, cambic B horizons, and deep rooting profiles. High water tables sites ha d higher organic matter, total nitrogen, cation exchange capacity, and extr actable potassium, but lower pH than low water table sites. Also, high wate r table sites had lower percentage sand, lower bulk densities, and higher s oil moisture retention. The importance of organic matter was evidenced by s trong positive product moment correlations for organic matter and total nit rogen, cation exchange capacity, and extractable potassium. Significant dif ferences in pH, extractable potassium and extractable phosphorus existed am ong drainages that were explainable largely from the parent materials. Drai nages with chert, quartzite, and limestone had higher silt and clay, neutra l pH, and high levels of extractable phosphorus. Drainages formed in acidic volcanic tuffs, rhyolites and breccia were characterized by coarser textur ed soils and low pH and extractable phosphorus. In riparian areas, soil wat er table depth interacts with soil parent material to significantly affect soil morphology and soil physical and chemical properties. Because these fa ctors vary over both large and small spatial scales, differences among site s must be carefully interpreted when classifying ecosystems or evaluating e cosystem condition.