Dataset

Database Code

SP020

Title

Effects of topography on soil characteristics in the Andrews Experimental Forest, 1998

Abstract

This is the third and final data set in a series of basin-scale summer forest soil surveys. We conducted soil survey in 1998 designed to provide an accurate assessment of soil properties over the entire H.J. Andrews Experimental Forest. This dataset represents the results of that effort. Since the 1994 survey, we changed the way we measured soil field respiration rates. Initially we used the 24 hr soda-lime CO2 adsorption method in chambers with only one measurement per site. In 1998 we converted to using the Li-Cor portable respirometer with 5 measurements made per site. Since 1994, it was also discovered that there were significant edge effects to 30 meters from an edge. For this reason, all sample locations were moved at least 40 meters from the road. While conducting autocorrelation analyses, we found that for the variables studied, samples collected at 5 m intervals were not autocorrelated and could thus be considered independent for statistical analysis. Our subsequent work also allowed us to chose those variables that would most likely be influenced by topography. The previous two surveys were conducted in the late summer when the forests are dry and microbial activity at a minimum. The current study was conduced from mid June to the first of July while the soils were still moist and when microbial activity was more typical of wet months. In the other two studies, only one measurement was made per site. In the current survey, replicate samples were collected and pooled or multiple measurements were made in the field. As a result of experimental design modifications, it is thought that this represents the best and most definitive dataset of basin-scale soil properties on the HJA. In the first survey, forest floor respiration rates were measured at 130 sites covering a large portion of the HJA. The sample sites were located at 0.5 km intervals along most of the main roads. In addition to field respiration rates measured by the soda-lime method, soil and air temperatures were recorded along with maximum and minimum soil temperatures for the 24 hr CO2 collection period. Only one measurement was made per site. These data and associated metadata can be found in database SP005 under the title of “H.J. Andrews 1993 REU synoptic soil respiration of permanent forest sites”. The following summer, a much more comprehensive study was conducted. The number of sites studied was expended to 183 sites located at 0.5 km intervals along all passable roads on the HJA. With the exception of the max-min soil temperature data, all variables measured in 1993 were repeated in 1994. In addition, the following variables were measured: pH, soil moisture, bulk density, soil organic matter, laboratory respiration (both long and short-term; with and without amendments), denitrification potential, extractable ammonium, and mineralizable nitrogen. In addition, we scored for the presence of moss on the surface and mycorrhizal mats found in 4.7 x 10 cm cores. These data and associated metadata are located in database SP006 entitled “H.J. Andrews 1994 REU study of soil chemical and microbiological properties”. The main objective of this study was to provide a broad overview of soil chemical and biological properties to guide us in future large-scale HJA soil surveys.

Keywords

soil properties; topography; inorganic nutrients; organic matter; Long-Term Ecological Research (LTER); inorganic nutrients; organic matter

Date begin

1998-06-15

Date end

1998-07-07

Principal Investigator

Robert P. Griffiths

Entities

1. SP02001
2. SP02002

1. SP02001 - Attribute list

2. SP02002 - Attribute list

Attribute definitions

AIRTEMP

Air temperature measured with Licor

ASPECT

Site aspect

BULKDENS

Bulk density

B_GLUC

Beta-glucosidase activity (dry weight basis)

CHANGES

Changes from original location done in 1998

COEFVARB

Coefficient of variability for repeated soil depth measurements

DBCODE

FSDB Database Code

DENIT

Denitrification potential (dry weight basis, as N)

DEPTH

Soil depth to bedrock

DIRECTION

Site direction from road

ELEVATION

Elevation of site

ENTITY

Entity number

EXAMM

Extractable ammonium (dry weight basis)

FLDRESP

Field respiration rates

GAUT

Percentage of core containing mycorrhizal mats like those of the genus Gautieria

HYSTER

Percentage of core containing mycorrhizal mats like those of the genus Hysterangium

LABRESP

Laboratory respiration rates (dry weight basis, as C)

LATITUDE

Latitude of site

LIGHT

Amount of light measured with Licor

LITTER

Litter depth

LOCATION

Site location

LONGITUDE

Longitude of site

MINN

Mineralizable nitrogen (dry weight basis)

MOIST

Percent moisture

PH

pH

POSITION

Position relative to road

SOILTEMP

Soil temperature measured with Licor

SOM

Soil organic matter

SSSG_SITE

Soil synoptic sample grid sitecode

STANDAGE

Stand age

VEGETATION

Codes of vegetation present at site

YEAR

Year of sampling

Enumerated domains

Enumerated domain for attribute: DBCODE

Enumerated domain for attribute: SSSG_SITE

Enumerated domain for attribute: ASPECT

Enumerated domain for attribute: DIRECTION

Enumerated domain for attribute: STANDAGE