Soil water dynamics at 15 locations distributed across a desert landscape: Insights from a 27-year dataset

Authors: DUNIWAY, MICHAEL - Us Geological Survey (USGS); PETRIE, MATTHEW - New Mexico State University; Peters, Debra; ANDERSON, JOHN - New Mexico State University; CROSSLAND, KEITH - Natural Resources Conservation Service (NRCS, USDA); Herrick, Jeffrey - Jeff

Submitted to: Ecosphere
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/22/2018
Publication Date: 7/1/2018
Citation: Duniway, M.C., Petrie, M., Peters, D.C., Anderson, J., Crossland, K., Herrick, J.E. 2018. Soil water dynamics at 15 locations distributed across a desert landscape: Insights from a 27-year dataset. Ecosphere. 97:e02335. https://doi.org/10.1002/ecs2.2335.
DOI: https://doi.org/10.1002/ecs2.2335

Interpretive Summary: We report on 27 years of daily volumetric soil water content (VWC) data from 15 locations distributed across 5 ecosystem types with different soil properties at the Jornada Experimental Range in the northern Chihuahuan Desert. Our results that depth and temporal patterns in soil water vary strongly with patterns in soils and topographic setting. Results emphasize the episodic nature of deep wetting events in our study system—essentially limited to three large events over the 27- year record driven primarily by wetter than normal winters. Comparison of soil water dynamics between mesquite shrub coppice dunes and interspace soils suggest the “island of fertility” concept does not extend to soil water. Median VWC was strongly coupled to climatic conditions over surprisingly long windows at most locations (6 – 18 months) suggesting that soil water at depth is decoupled from short climatic pulses. There were also some unexpected similarities in ecohydrologic dynamics among very different vegetation types (e.g. an eroded creosote shrubland and a playa grassland). These observations further underscore the need for long-term data from multiple, constrasting locations to tease apart the controllong factors on sol water, a dominant driver of dryland ecosystems.

Technical Abstract: Desert ecosystems are primarily limited by water availability. Within a climatic regime, topography, soil characteristics, and vegetation are expected to determine how the combined effects of precipitation, temperature, and evaporative demand of the atmosphere shape the spatial and temporal patterns of water within the soil profile and across a landscape. To forecast how desert landscapes may respond to futureclimatic conditions, it is imperative to improve our understanding of these ecohydrologic processes. Here, we report on 27 years of monthly soil volumetric water content (VWC) measurements and associated soils data from a site in the northern Chihuahuan Desert of North America. The dataset includes VWC and soil properties measured to 3-m in depth across 15 locations that encompass a range of Chihuahuan Desert vegetation types. We use this unique data set (1) to generate insights into general temporal and depth patterns in VWC, (2) to analyze how VWC corresponds to measures of climatic conditions, and (3) to qualitatively evaluate the relative importance of soils, topographic setting, and vegetation type in mediating temporal patterns in VWC. Analysis of this unique dataset emphasize the importance of soil and topographic setting in determining depth and temporal patterns in VWC across time. Results emphasize the episodic nature of deep wetting events in our study system—essentially limited to three large events over the 27- year record driven primarily by wetter than normal winters. Comparison of soil water dynamics between mesquite shrub coppice dunes and interspace soils suggest the “island of fertility” concept does not extend to soil water. Median VWC was strongly coupled to climatic conditions over surprisingly long windows at most locations (6 – 18 months) suggesting that soil water at depth is decoupled from short climatic pulses. However, VWC dynamics and VWC-climate relationships varied among locations, depths, and seasons, with unexpected similarities in ecohydrologic dynamics observed among very different vegetation types (e.g. an eroded creosote shrubland and a playa grassland). These results further underscore the importance of ecohydrological investigations in these ecosystems, given forecasts for a warmer and more variable climates in deserts globally.