USGS Science⌕ Search
Home/Archive/USGS

USGS · 70102160

Soil-plant-microbial relations in hydrothermally altered soils of Northern California

S.W. Blecker·L.L. Stillings·N.M. DeCrappeo·J.A. Ippolito
View original source ↗Export metadata ↓

Abstract

Soils developed on relict hydrothermally altered soils throughout the Western USA present unique opportunities to study the role of geology on above and belowground biotic activity and composition. Soil and vegetation samples were taken at three unaltered andesite and three hydrothermally altered (acid-sulfate) sites located in and around Lassen VolcanicNational Park in northeastern California. In addition, three different types of disturbed areas (clearcut, thinned, and pipeline) were sampled in acid-sulfate altered sites. Soils were sampled (0–15 cm) in mid-summer 2010 from both under-canopy and between-canopy areas within each of the sites. Soils were analyzed for numerous physical and chemical properties along with soil enzyme assays, C and N mineralization potential, microbial biomass-C and C-substrate utilization. Field vegetation measurements consisted of canopy cover by life form (tree, shrub, forb, and grass), tree and shrub density, and above-ground net primary productivity of the understory. Overall, parameters at the clearcut sites were more similar to the unaltered sites, while parameters at the thinned and pipeline sites were more similar to the altered sites. We employed principal components analysis (PCA) to develop two soil quality indices (SQI) to help quantify the differences among the sites: one based on the correlation between soil parameters and canopy cover, and the second based on six sub-indices. Soil quality indices developed in these systems could provide a means for monitoring and identifying key relations between the vegetation, soils, and microorganisms.

Explore related subjects

Soil Science Society of America JournalArticle

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

S.W. Blecker, L.L. Stillings, N.M. DeCrappeo, J.A. Ippolito. 2014-02-21. Soil-plant-microbial relations in hydrothermally altered soils of Northern California. https://doi.org/10.2136/sssaj2013.07.0298

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related USGS reports

USGS2024

Estimates of soil taxonomic change due to near-surface permafrost loss in Alaska

Gelisols (permafrost-affected soils in U.S. Soil Taxonomy) are extensive in Alaska, currently occurring on approximately 45% of the land area of the state. Gelisol taxonomic criteria rely on the presence of near-surface (less than 2m deep) permafrost, but ongoing climatic and environmental change has the potential to affect the presence of near-surface permafrost across much of Alaska throughout the 21st century. In this study, we utilized scenarios of near-surface permafrost loss and active layer deepening through the 21st century under low (SRES B1, RCP 4.5), mid- (SRES A1B) and high (SRES A2, RCP8.5) emissions scenarios, in conjunction with the statewide STATSGO soil map, to generate spatially-explicit predictions of the susceptibility of Gelisols and Gelisol suborders to taxonomic change in Alaska. We find that 15-53% of Alaskan Gelisols are susceptible to taxonomic change by mid-century and 41-69% of Alaskan Gelisols are susceptible to taxonomic change by the end of the century. The extent of potential change varies between suborders and geographic regions, with Gelisols in Northern Alaska being the most resilient to taxonomic change and Western and Interior Alaskan Gelisols most susceptible to taxonomic change. The Orthel suborder is likely to be highly restricted by the late 21st century, while Histels and Tubels are more likely to be of greater extent. These results should be taken into consideration when designing initial survey and re-mapping efforts in Alaska, and suggest that Alaskan Gelisol taxa should be considered threatened soil taxa due to the proportional extent of likely loss.

Alaska↗
USGS2023

Forming regional soil carbon networks to support effective climate change solutions

Sequestration and storage of organic carbon (C) in soil is an essential component of climate change mitigation and fundamental in promoting the health and climate resilience of soils. Sources of available soil C data are increasing, which complicates efforts to consolidate the data in forms that can be readily used by stakeholders. Spatial and temporal gaps in data availability also limit the quantification of changes in soil C through space and time. Improved coordination among producers and users of soil C data would provide data compatibility at the spatial and temporal resolution required for C monitoring, accounting, and verification of policy implementation. These challenges can be addressed by forming regional-scale networks to coordinate the collection and use of soil C data by promoting consistency in methods, collecting new data to fill critical gaps, integrating existing data from multiple sources, and providing data interpretation to stakeholders in readily usable forms. Forming networks in regions such as the Northeastern United States would require close coordinationwith existing programs that are involved in collecting or aggregating soil C within that region. Network formation could be accomplished by (1) producing a planning document, (2) designing a network structure tailored to the region, and (3) acquiring the institutional support to establish and operate the network. Increasing the availability and usage of soil C data through regional networks would support the development of climate change solutions and increased ecosystem services through land management efforts that increase soil C storage.

Soil Science Society of America Journal↗
USGS2021

The processes of preferential flow in the unsaturated zone

Preferential flow, a major influence in unsaturated soil and rock almost everywhere, occurs by multiple phenomenologically distinct hydraulic processes. For the mode known as funneled flow, concentrated in particularly conductive portions of the medium, the surface-tension/viscous-flow processes of traditional unsaturated flow theory predominate. Fingered flow, through conductive paths of higher water content than surrounding material, requires amendments to traditional theory concerning instabilities and dynamic flow-regime boundaries. Macropore flow, the most recognized preferential flow mode, poses unanswered questions and major difficulties in practice. Accumulated evidence shows that water flows preferentially mostly through macropores that are (a) only partially filled with water, and (b) surrounded by matrix material that is drier, sometimes much drier, than saturation. With partial filling, geometric characteristics such as aperture have much less influence than was previously thought, and the intra-macropore configuration of the flowing water phase, about which little is conclusively known, is then a dominant controlling influence. With unsaturated surroundings, macropore/matrix exchange interactions control, for given input and medium, the initiating circumstances, conveyed flux, and duration of macropore flow. The multiple processes in play during such interactions have different sensitivities to the matrix water state and different directions of influence. The net influence of matrix water content on macropore flow is thus highly complex and a major research need. Additional high-priority topics are: flowpath connectivity, for watersheds as well as small scales; intra-macropore processes, to discern their importance and possible means of quantification; and the identification of measurable soil and rock properties that can be utilized predictively.

Soil Science Society of America Journal↗