Subsurface soil textural control of aboveground productivity in the US Desert Southwest

The drylands of the US Desert Southwest (SW) are dependent on precipitation stored as soil moisture for aboveground productivity. Availability of soil moisture in dryland systems is a function of climate and soil physical properties; however, we lack accurate understanding of how soil physical properties modulate regional patterns of aboveground productivity responses to climate forcing in the SW. We used established regional soil, vegetation, and climate datasets to quantify differences in vegetation productivity attributable to soil texture and climate forcing. Subsurface soil texture accounted for significant variation in aboveground productivity in the winter and fore-summer months, but not during the summer monsoon. Subsurface soil texture differences were more important in the Mojave and Sonoran Deserts, which receive significant winter precipitation. Subsurface soil texture is a significant determinant in modulating aboveground productivity, linked to winter precipitation storage as soil moisture, suggesting that drying winters may lead to increased dryland ecosystem stress.