Soils & Nutrients

We expect that plants may respond differently to land management treatments due to differences in the soils found on the research sites. Soil sampling will be conducted to provide descriptive information on research site soils to help explain differences in vegetation responses within and across sites. Features such as geomorphic setting, slope, and aspect will be recorded, and soil properties will be described, including color, structure, consistency, root abundance and architecture, coarse-fragment abundance, texture, presence, bulk density, and any special features.

Response of soils to the land management treatments will also be assessed. Soil chemistry parameters will be evaluated before, immediately after, and two years after treatment implementation.

Soil water availability is a critical variable to measure, because it will very likely contribute to differences in vegetation response to treatments. The following questions will be addressed with information on soil water availability:

• What are the effects of increasing tree dominance and loss of native understory plants in pinyon-juniper woodlands, or of decreasing understory perennial species in sagebrush, on soil water availability?

• Are there soil water availability thresholds that correlate with vegetation thresholds?

• What are the effects of vegetation disturbance for different suspected understory thresholds on soil water availability?

• What are the available water/soil temperature conditions that affect recovery of desirable plant species versus weed invasion?