CAP LTER Survey200 Field Protocol

Version 2015

These methods were adapted from the CAP LTER Ecological Survey of Central Arizona protocol. This protocol was based initially on the UFORE FOREST SURVEY devised by Dave Nowak (BES), and has been updated with input from CAP LTER PIs and field experience. The protocol adapted was specific to the survey conducted in 2015. The 2015 survey, for the first time, employed the use of digital tablets for data collection in the field, and the steps in this protocol that reference ODK are noting the appropriate form in the tablet to employ for a particular type of data. These methods are otherwise identical to protocols of previous surveys.

Arriving at the site: first steps

Upon arriving at a site, use the Trimble GPS to locate the plot center (locate the nail if present (desert sites only)). Create a new folder inthe GPS for the site, and record the location of the plot center. If present, always use the center nail as plot center and record thislocation as plot center in the GPS. Use the Trimble GPS to identify the plot corners and mid-points - mark these with flags or cones. At plots with relatively little topography, it may be easier to use pre-measured 30m ropes laid along the N-S and E-W axes of the plot to delineate the plot boundary. Divide tasks among crew members.

General plot information

ODK form: s200_GPI

• Note the plot ID (for example, 'V12')
• Note plot (see parcel instructions below for parcels)
• Crew members: check all that are present, and note additional crew members not included in the list (add a new 'AdditionalCrew' group)
• Inclination: identify the steepest section of the plot; one person stands at top while another person stands some distance downhill; person at top uses clinometer to measure angle (in degrees) down to eye level of the other person
• Exposure: note predominant aspect of the plot (if there is any slope)
• Provide a brief description of the plot. Limit description to ~20 words and use keywords, such as desert, creosote flat, residential neighborhood, strip mall parking lot, etc.
• Quantify land use of the plot (only of the plot; add 'landuses_sampling_event' group): percent of the plot area that is in the land use using the LTER land use categories 1 through 6. This will often be 100% (e.g., desert sites) but some plots will cover multiple categories (e.g., 60% residential, 40% street). Make sure percentages sum to 100%. Identify categories using supplied codes (e.g., 1B1 for institutional (schools, churches, etc) sites).
• Note the use of buildings on the plot
• Record heights of buildings if present (add 'Plot structures' group): record the slope (in degrees) to the highest point and bottom of the structure from a known distance.
• Note surrounding transportation infrastructure that best reflects conditions at the plot
• Note current weather
• Note if it has rained and what evidence if so
• Visible human activity (not applicable in private back yards): excluding conditions in private back yards, note signs of human activity within the plot corresponding to the checklist.
• Evaluation of surrounding neighborhood: excluding outlying desert areas, note general characteristics of the surrounding neighborhood.
• Note whether the plot center nail was located and whether one was left
• Note landscape practices (skip for desert plots) Does the landscape have a natural or manicured appearance? Is the landscape maintained professionally? Are plants in the landscape healthy and vigorous? Are there any symptoms or signs of abiotic or biotic injury? Watering regimes: drip or trickle, overhead spray, flood, hand watering, or not irrigated Estimate % of pervious area irrigated. Veg types present: soil / trees / shrubs / succulents / herbaceous groundcover / other groundcover

Photographs

Photos taken at plot center (to be taken with digital SLR fitted with 28mm lens)

• Photographer should stand at plot center and take one photo in each cardinal direction
• Be sure that crew members nor the vehicle are in the field of view for plot center photos.
• Where plot center is inaccessible, note location where photos were taken in the 'notes concerning plot photos' field
• Camera height should be ~1.5 m or ~5 ft (always have a crew member of approximately this height take photos)
• Note photo numbers in the form

Synoptic Plot Photos

• At the photographer's discretion, take photos with the tablet to capture the 'essence' of the plot. These are most often taken from outside plot boundary looking toward plot center (and other angles as appropriate) but not necessarily.
• Describe each photo in the description box.

Vegetation

ODK forms: s200_trees_plot, s200_shrub_survey; s200_shrub_count; s200_hedges_survey, s200_annuals

Trees and saguaros

ODK form: s200_trees_plot

• Note the plot ID (for example, 'V12')
• ALL trees (including all palms) and saguaros in the plot are counted, measured, photographed, and their position recorded
• Add a 'Tree Data' group for each tree in the plot
• Note the ID of the tree if this information is known, knowable only by examining previous data sheets or from past Trimble files - you are unlikely to have this information
• Note the tree taxon. Select 'other' if the identity is not known. Record a new taxon or provide notes about the tree's identity if relevant.
• Take a photo of the tree
• Record the GPS position of the tree
• Note if a voucher was collected
• If a voucher was collected, provide information about the voucher in 'voucher details' - in most cases, this will simply be the tree number but provide additional information if relevant. Collect a small sample. Collect specimens that have flowers, fruits, and roots when possible. Write "perennial" on herbarium envelope.
• Note the shape and class of each tree (not applicable in desert plots)
• Note if the tree is also in a parcel (urban sites only)
• Note the tree shape
• Note the tree class (not applicable in desert plots)
• Estimate the health of the canopy based on the condition of the leaves (% dead or senesced)
• Estimate the % of the canopy that is absent from a perfect circle or oval
• Measure stem diameter as Diameter at Breast Height (DBH 54") of all stems at breast height. If this is not feasible (e.g., many small stems that would yield a poor estimate of girth), record the trunk diameter at, preferably, ground height (DGH, diameter at ground height, where trunk emerges from ground), or, less desirable, at some other height. Note the measuring height (inches) and diameter on data sheet. For trees where multiple trunks are measured, sum the values and report only the total number, note also the number of stems/trunks measured.
• Tree height: where possible, measure height of the tree and the bottom of the canopy directly with a measuring tape. Otherwise, from a known (and measured) distance where you can see the top and base of the tree, use a clinometer to record the angle (degree, left-side scale of clinometer) to the top of the tree, and angle to base of the tree (where the trunk emerges from the ground).
• Canopy dimensions. Record the length of the living canopy along the N-S axis and E-W axes using a measuring tape. Measure the height to the bottom of the canopy above the ground. This is best addressed by using a meter tape but can be done with the clinometer if necessary. If using a clinometer, record the angle to the bottom of the canopy from a known distance.
• Record the position of the tree in the plot relative to plot center if GPS is not available.
• Add another 'Tree Data' group for additional trees

Shrubs, perennial groundcover, and cacti other than saguaros

ODK forms: s200_shrub_survey; s200_shrub_count; s200_hedges_survey

shrub count

ODK forms: s200_shrub_count

ALL shrubs and cacti in the plot are counted by species, segregated by quadrant (to aid counting). Note that this does not include saguaros, which are treated like trees.

• Note the plot ID (for example, 'V12')
• Note plot (see parcel instructions below for parcels)
• Note the shrub taxon. Select 'other' if the identity is not know. Record a new taxon or provide notes about the plant's identity if relevant.
• Take a photo of the plant if relevant. Pictures of each plant are not required here, but take photos if the ID is questionable or if there is something unique about the plant(s) or setting that would be useful to document with a photograph.
• Note if a voucher was collected
• If a voucher was collected, provide information about the voucher in 'voucher details' - in most cases, this will simply be the shrub number but provide additional information if relevant. Collect a small sample. Collect specimens that have flowers, fruits, and roots when possible. Write "perennial" on herbarium envelope.
• Quantify the number of this type of shrub in each quadrant of the plot. Note that the quadrant distinction is not overly important and is primarily added to aid counting in plots with high densities of shrubs, so focus on getting an accurate estimate of the number of shrubs and less about their exact location.

shrub survey

ODK forms: s200_shrub_survey

The characteristics of at least 5 representative individuals of each shrub and cacti species (at least 1 from each quadrant when possible) are recorded in the s200_shrub_survey form. As with the shrub count, this does not include saguaros, which are addressed with the trees.

• Note the plot ID (for example, 'V12')
• Add a 'Survey data for taxon' group for each taxon in the plot
• Note the plant taxon. Select 'other' if the identity is not know. Record a new taxon or provide notes about the plant's identity if relevant.
• Take a photo of the plant if relevant. Pictures of each plant are not required here, but take photos if the ID is questionable or if there is something unique about the plant(s) or setting that would be useful to document with a photograph.
• Note if a voucher was collected
• If a voucher was collected, provide information about the voucher in 'voucher details' - in most cases, this will simply be the shrub number but provide additional information if relevant. Collect a small sample. Collect specimens that have flowers, fruits, and roots when possible. Write "perennial" on herbarium envelope.
• Add a 'Survey of plants of a given taxon' group
• Note the shape and class of the plant (not applicable in desert plots)
• Plant dimensions: where possible, measure height of the plant directly with a measuring tape. Otherwise, from a known (and measured) distance where you can see the top and base of the plant, use a clinometer to record the angle (degree, left-side scale of clinometer) to the top of the plant, and angle to base of the plant (where the plant emerges from the ground).
• Canopy dimensions. Record the length of the living canopy along the N-S axis and E-W axes using a measuring tape.
• For each additional plant of this taxon, add a 'Survey of plants of a given taxon' group
• Add another 'Survey data for taxon' group for additional taxa.

Hedges (urban plots only)

ODK forms: s200_hedges_survey

A hedge versus a shrub is an arbitrary distinction to be made by the crew on site. Typically, we consider a shrub or shrubs(s) a hedge if it or, most often, they are positioned and manicured to create a distinct border, and if the growth of the plants is dense.

The taxon, size, and shape of ALL hedges is recorded in the Hedges box of the vegetation data sheets. The number of hedges at each site should correspond to the number of entries on this sheet (i.e., there is not a separate hedge count sheet as there is for shrubs).

• Note the plot ID (for example, 'V12')
• Add a 'Survey data for taxon' group for each taxon in the plot
• Note the plant taxon. Select 'other' if the identity is not know. Record a new taxon or provide notes about the plant's identity if relevant.
• Take a photo of the plant if relevant. Pictures of each plant are not required here, but take photos if the ID is questionable or if there is something unique about the plant(s) or setting that would be useful to document with a photograph.
• Note if a voucher was collected
• If a voucher was collected, provide information about the voucher in 'voucher details' - in most cases, this will simply be the hedge number but provide additional information if relevant. Collect a small sample. Collect specimens that have flowers, fruits, and roots when possible. Write "perennial" on herbarium envelope.
• Add a 'Survey of hedges of a given taxon' group
• Note the shape and class of the hedge
• Plant dimensions: where possible, measure height of the plant directly with a measuring tape. Otherwise, from a known (and measured) distance where you can see the top and base of the plant, use a clinometer to record the angle (degree, left-side scale of clinometer) to the top of the plant, and angle to base of the plant (where the plant emerges from the ground).
• Canopy dimensions: record the length (long axis) and width (short axis) of the living canopy of the hedge using a measuring tape.
• For each additional plant of this taxon, add a 'Survey of hedges of a given taxon' group
• To continue with additional species, add another 'Survey data for taxon' group

Annuals

ODK forms: s200_annuals

Treat grasses and herbs as annuals

• Note the plot ID (for example, 'V12')
• Estimate the percent cover of annuals in the plot by the linear extent of annuals in contact with virtual lines that bisect the plot. Measure cover in 0.25 m increments, and include only coverage that is at least 0.25 m in length.
• Add a 'Survey data for taxon' group for each taxon in the plot
• Note the plant taxon. Select 'other' if the identity is not know. Record a new taxon or provide notes about the plant's identity if relevant.
• Note if the identify of the sample is known (with certainty)
• Note if a voucher was collected
• If a voucher was collected, provide information about the voucher in 'voucher details' - in most cases, this will simply be the shrub number but provide additional information if relevant. Whenever possible, collect specimens that have flowers, fruits, and roots - flowers are always a priority!
• Take a picture of every annual by adding an 'annuals photos' group. For annuals, you can take multiple photos of each plant if desired. Be sure to have at least one photo that features the plant and the herbarium voucher labeled with as much information as possible (site ID, sample number, sampling date, photo number, and taxon if known) included in the backdrop (use a piece of blank, white paper as a background for the specimen and voucher packet).
• After photographing the specimen and voucher packet, place the specimen in the voucher packet and bundle packets for that site. When placing the specimen into the voucher packet, flatten leaves and spread them out as much as possible.
• continue to add a 'Survey data for taxon' group for each taxon in the plot
• Voucher packets are pressed in the lab the day they are collected. When a press is full, place it in the air-dryer in the Herbarium for ≥1 week, then move the press to the Herbarium freezer for ≥2 days. After this time, remove the packets from the press and place them in the survey200 Herbarium cabinet.

Soil sampling

ODK form: s200_GPI

Soil cores - overview

• The goal is to collect four 1" soil cores for chemical analyses at multiple depths, and one 2" soil core for analyses of soil physical properties at each site.
• The preferred sampling locations for each of the 1" cores is 10 m in each cardinal direction, shifted 1.0 m clockwise; and 1.0 m east of plot center for the single 2" core
• At desert sites, rocky conditions may prevent sampling at preferred locations - a suitable location near to the preferred spot should be located.
• The preferred sampling locations at urban sites are rarely accessible, and, as at desert sites, a suitable location near to the preferred location should be identified (note this system breaks down considerably given the habitat of many urban sites (e.g., houses, driveways, etc); in those instances, collect samples wherever possible striving to capture best the diversity of soil conditions at the site). Further, it may not be possible to collect 4 1"-cores at urban sites due to extensive irrigation, limited access to the plot (e.g., access to only one of several yards), etc. In those situations, collect as many 1" cores as possible, again striving to cover the diversity of soil types and cover at the site. At some locations, it may not be possible to collect any 1" cores due to the aforementioned conditions.
• Record the location where cores were collected. Ideally, the location of each position should be recorded with the tablet. As a backup, the location can be described in the soil core location description boxes (see next step).
• Provide a brief description of the conditions where each soil was collected (e.g., gravel area of side yard, turf area of playground).

Soil cores – detailed instruction

• 2" soil core carefully take an intact core ~1 m east of plot center IF there is no danger of hitting irrigation/power lines or the nearest location to plot center with representative ground cover if the core is incomplete, remove the soil and collect another sample Avoid pushing/compacting the sample when removing from corer Place a red cap on top of the core sleeve and a blue cap on the bottom of the core sleeve Label core sleeve with the plot ID and date
• 1" soil cores collect 4 samples, ~10 m North, South, East and West of plot center and 1 m clockwise from transect, or the nearest feasible location to these positions Do not sample where there may be irrigation/power lines if the core is incomplete, remove the soil and collect another sample Avoid pushing/compacting the sample when removing from corer Place a red cap on top of the core sleeve and a blue cap on the bottom of the core sleeve

Surface soil – overview

A total of four surface soil (2-cm depth) samples are to be collected, one corresponding to each of the 1" soil core locations. Sweep aside gravel and loose vegetation before collecting sample, but do not collect samples from thick turf. In fact, it may not be possible to collect surface soil samples at sites where thick turf or impervious substrates are predominant. As much as possible, surface-soil samples should be collected in conjunction with the 1" soil cores but it is not essntial that they overlap if one or the other type of sample is not feasible. It is not necessary to record the GPS location of surface soil samples.

Surface soil – detailed instruction

• Collect a single surface soil sample as near as possible to where 1" soil cores were collected (n = 4)
• Sweep aside gravel or loose vegetation, and place the copper coupling on soil where sample is to be taken. Sample soil that does not have vegetation cover (i.e., in a site where grass is growing near core location, move to nearest place without grass to sample surface soil).
• Hammer the copper ring into soil to a depth of 2 cm
• Collect soil to depth corresponding to the bottom of ring using a spoon, and place soil in Ziploc bag
• Label Ziploc bag with plot ID, date, and location.

Arthropods (sweep-net samples)

ODK form: s200_GPI

Arthropods – overview

Collect a sample of vegetation-dwelling insects from three different plants (preferably each a different species) at each site. At least one insect sample should reflect the dominant plant species at each site. The second and third samples should reflect other dominant plants at the site (including one or more ground sweeps if the site is dominated by turf of weeds), and preferred plants as follows:

• Bougainvillea spp. (in mesic and xeric residential neighborhoods)
• Citrus spp. (in mesic yards and in orchards, i.e., agriculture)
• Encelia farinosa (in desert sites and xeric yards)
• Larrea tridentata (in desert sites and xeric yards)
• Nerium oleander (commercial sites, mesic yards, xeric yards)
• Cupressus spp. (commercial sites, mesic yards)
• Olea spp. (commercial sites, mesic yards)
• Prosopis spp. (agriculture, desert, mesic, xeric)

Conduct ground sweeps at sites where only turf or weeds are present. In the absence of any vegetation, collect samples from off plot at a location that is representative of the plot.

Sweep-net samples – detailed instructions

• select plant (see above)
• envelop one branch of selected plant with the sweep net
• shake the branch vigorously ten times
• remove the net from the branch (or vice versa) quickly, and choke the top of the net so flying insects cannot escape
• hold the net vertically and shake it such that the insects fall to the closed-end of the net (you can also open the net and wave it rapidly several times – this works particularly well for manipulating flying insects to the tip of the net).
• place an open insect jar over white paper
• hold the net vertically, and slowly move your choke-hold on the net toward the tip as you shake continuously.
• when your choke-hold on the net is very near the tip, grab the tip of the net (while maintaining your choke-hold), and slowly invert the tip of the net into an open sample jar and shake, flick, and prod all contents into the jar
• shake anything that falls on the white paper into the jar
• add completed sample tag (filled out using pencil (not pen!)) to the jar, and close tightly
• note the taxa of each plant from which a sample was collected

Before leaving the site

• Confer with team members that all data were collected and all relevant data forms were addressed
• Be sure insect jars are stowed upright
• Be sure soil samples are collected from the backpacks and transferred to a storage container
• Be sure to collect all plant voucher packets, and that they are bundled by site

At the lab

• Create a new folder (identified by site ID) for each site visited that day on the designated shared drive.
• Upload all photos and the GPS file for each site into the respective aforementioned folder. When uploading photos, be sure to copy and paste directly from the camera (by way of a file browser) to the desired location as opposed to using camera-provided software as the software WILL change the name/number of the photo causing quite a problem
• There is a folder on the shared drive for each tablet (Alpha, Bravo, Charlie). Within each of those folders, create a folder with the first letter of the tablet (a, b, or c) and the date as MMDD (e.g., tablet Bravo for the day March 8, 2015 would have the folder name b0308). Copy the ODK folder in the tablet to the folder on the shared drive that was just created.
• Add voucher packets to a plant press. When a press is full, place it in the air-dryer in the Herbarium for ≥1 week, then move the press to the Herbarium freezer for ≥2 days. After this time, remove the packets from the press and place them in the survey 200 Herbarium cabinet.
• Place all soil samples at the designated location in the walk-in lab cooler

Parcel survey

At all residential sites, survey characteristics of the parcel that most overlaps with the 30x30m study plot – if not accessible, survey the parcel that is most accessible. Data are to be collected for both the front and back yards if accessible.

General parcel information

ODK form: s200_GPI

• Note the plot ID (for example, 'V12')
• Note parcel
• Note the parcel address
• Quantify land use of the plot (only of the plot; add 'landuses_sampling_event' group): percent of the plot area that is in the land use using the LTER land use categories 1 through 6. This will often be 100% (e.g., desert sites) but some plots will cover multiple categories (e.g., 60% residential, 40% street). Make sure percentages sum to 100%. Identify categories using outline codes (e.g., 1B1 for institutional (schools, churches, etc) sites).
• Note the use of buildings on the plot
• Record heights of buildings if present (add 'Plot structures' group): record the slope (in degrees) to the highest point and bottom of the structure from a known distance.
• Note surrounding transportation infrastructure that best reflects conditions at the parcel
• Note landscape practices Does the landscape have a natural or manicured appearance? Is the landscape maintained professionally? Are plants in the landscape healthy and vigorous? Are there any symptoms or signs of abiotic or biotic injury? Watering regimes: drip or trickle, overhead spray, flood, hand watering, or not irrigated Estimate % of pervious area irrigated. Veg types present: soil / trees / shrubs / succulents / herbaceous groundcover / other groundcover
• Synoptic Plot Photos: take synoptic photos of the parcel to capture the essence of the plot; describe each photo in the description box.
• Note the type of residence
• Note approximate perceived social class of the neighborhood

Yard characteristics & features

• For front and rear yards separately, note the qualities as prompted by the form yard upkeep yard orderliness yard features watering regimes yard landscape type amount of grass and characteristics (if present) weeds pruning detailed assessment of grass (if present)

Add another 'front or back yard' group as access allows

Vegetation

ODK forms: s200_trees_parcel, s200_shrub_count

Trees and saguaros

ODK form: s200_trees_parcel

• Note the plot ID (for example, 'V12')
• ALL trees (including all palms) and saguaros in the yard(s) are counted, measured, photographed, and their position recorded
• Note front or back yard assessment
• Add a 'Tree Data' group for each tree in the plot
• Note the ID of the tree if this information is known, knowable only by examining previous data sheets or from past Trimble files - you are unlikely to have this information
• Note the tree taxon. Select 'other' if the identity is not know. Record a new taxon or provide notes about the tree's identity if relevant.
• Take a photo of the tree
• Record the GPS position of the tree
• Note if a voucher was collected
• If a voucher was collected, provide information about the voucher in 'voucher details' - in most cases, this will simply be the hedge number but provide additional information if relevant. Collect a small sample. Collect specimens that have flowers, fruits, and roots when possible. Write "perennial" on herbarium envelope.
• Note the shape and class of each tree
• Note if the tree is also in a plot
• Note the tree shape
• Note the tree class
• Estimate the health of the canopy based on the condition of the leaves (% dead or senesced)
• Estimate the % of the canopy that is absent from a perfect circle or oval
• Measure stem diameter as Diameter at Breast Height (DBH 54") of all stems at breast height. If this is not feasible (e.g., many small stems that would yield a poor estimate of girth), record the trunk diameter at, preferably, ground height (DGH, diameter at ground height, where trunk emerges from ground), or, less desirable, at some other height. Note the measuring height (inches) and diameter on data sheet. For trees where multiple trunks are measured, sum the circumferences and report only the total number, note also the number of stems measured.
• Tree height: where possible, measure height of the tree and the bottom of the canopy directly with a measuring tape. Otherwise, from a known (and measured) distance where you can see the top and base of the tree, use a clinometer to record the angle (degree, left-side scale of clinometer) to the top of the tree, and angle to base of the tree (where the trunk emerges from the ground).
• Canopy dimensions: record the length of the living canopy along the N-S axis and E-W axes using a measuring tape. Measure the height to the bottom of the canopy above the ground. This is best addressed by using a meter tape but can be done with the clinometer if necessary. If using a clinometer, record the angle to the bottom of the canopy from a known distance.

A special note about trees in the parcel: unlike the s200_shrub_count and s200_GPI forms that allow you to address both the front and back yards in a single instance, a new form/instance must be created for each the front and back yards when surveying trees.

Shrubs and cacti other than saguaros (shrub count):

ODK forms: s200_shrub_count

ALL shrubs and cacti in the yard(s) are counted by species, segregated by yard position (front, year). Note that this does not include saguaros, which are treated like trees.

• Note the plot ID (for example, 'V12')
• Note parcel
• Add a new 'front or back yard'
• Note the yard position (front, rear)
• Add a 'Survey data for taxon' group for each taxon
• Note the shrub taxon. Select 'other' if the identity is not know. Record a new taxon or provide notes about the plant's identity if relevant.
• note if the plant is a hedge
• Take a photo of the plant if relevant. Pictures of each plant are not required here, but take photos if the ID is questionable or if there is something unique about the plant(s) or setting that would be useful to document with a photograph.
• Note if a voucher was collected
• If a voucher was collected, provide information about the voucher in 'voucher details' - in most cases, this will simply be the shrub number but provide additional information if relevant. Collect a small sample. Collect specimens that have flowers, fruits, and roots when possible. Write "perennial" on herbarium envelope.
• Quantify the number of this type of plant in this particular yard (front, rear)
• Add a 'Survey data for taxon' group for each additional taxon
• Add another 'front or back yard' group note that you can end the survey and create a new form/instance of the 'other' yard if not convenient to measure at that time

200 Survey Soil Prep Step-by-Step Instructions

version 2015

A. Processing Bulk Density Soils (2 inch core)

1. Record height of soil in core tube (in cm) from the bottom up. Leave caps on. Blue cap is bottom, red is top. Measure 2 opposite sides and take the average. Record site and location info.
2. Wearing nitrile gloves use large wooden dowel to carefully remove red cap. If soil is loose, use dowel to loosen cap, then twist off with your hand holding core tube upright to prevent spillage.
3. Tare large aluminum tray on the 12kg balance (the big one). Empty contents of core tube into tray and record weight. If contents don’t readily empty from core tube, you will have to scoop out soil with a spatula, or try pushing out with large dowel. Tapping the side of the core tube with the large dowel sometimes dislodges the core.
4. After weighing, carefully dump soil from large tray into small aluminum baking pan. Take the taped label off the core tube and stick it firmly on the pan for identification. Let the pan + soil sit at room temp for 1 week.

After one week:

1. Empty contents of small baking pan into 2mm sieve and sieve by shaking side-to-side. Use large rubber stopper to break up large soil chunks and force them thru sieve. If the chunks are too hard to break up with stopper, you will have to use the large mortar and pestle. Empty soil into mortar and pound large soil chunks with pestle to break them down. Use a circular motion to grind them further if necessary. The object here is to loosen soil stuck to the stones. DO NOT grind stones to powder! Pick out any veg matter (roots, twigs, grass, leaves) with tweezers and set aside. Empty contents from mortar into 2mm sieve and re-sieve. Repeat as necessary until only stones greater than 2mm are left in the sieve.
2. Empty stones into a large aluminum tray that has been tared on the 12kg balance and record weight. Discard. Empty contents of receiving pan (the stuff that went thru the sieve – this is less than 2mm and is considered soil) into tared tray on 12kg balance and record weight. Weigh veg matter on the small 3100g balance and record, then discard. The stone and soil weights will be used to calculate bulk density.
3. Tare a small aluminum weighing pan on the 3100g balance and record weight. Put subsample of sieved soil (about 3 spatula scoops) into weighing pan and re-weigh. Record weight. Put pan + soil into 60 deg C oven for 48 hours. After 48 hours, remove pan + soil from oven and let cool 30 minutes. Then weigh again on 3100g balance. Record weight. Then place pan + soil into 105 deg C oven for 24 hours. After 24 hours, remove pan + soil from oven and let cool 30 minutes. Re-weigh and record weight. These data will be used to calculate moisture content.
4. After subsampling for moisture content, empty soil in small aluminum tray in labeled quart-size Ziploc bag. Store in sweater box. This is the bulk density soil sample that will be used for texture analysis

B. Processing 1 inch Core Samples (for chemical analyses)

1. Each site will have 4 cores. For each core, record height of soil in core tube (in cm) from the bottom up. Blue cap is bottom, red is top. If necessary measure 2 opposite sides and take the average. Record site and location info.
2. Separate core into 2 segments: top (0-10cm) and bottom (10cm-bottom of core). Do this as follows: wearing nitrile gloves, use the wooden dowel with the 10cm mark to extrude the core into a labeled quart-size Ziploc bag. Extrude up to the 10cm mark, separate the core, then extrude the remaining core into another labeled Ziploc bag. If core does not extrude easily or at all, and unfortunately most won’t, mark the 10 cm location on the core tube with a piece of tape. Use a plastic spatula to scoop the top core segment into a plastic weighing pan, then dump the contents of the pan into the Ziploc bag. Empty the bottom core segment into the other bag. Several taps on the core tube with the dowel is usually sufficient to dislodge the core. If the core is very moist, it may not slide out, and you will have to use a plastic spatula to scoop it out. A combination of scooping and tapping will eventually get it out. If the core is particularly dry and loose, leave the bottom cap on to prevent spills.
3. Once the core has been separated into 2 bags, tare the 12kg balance with an empty Ziploc bag, then weigh both top and bottom bags and record the fresh weight.
4. Wearing nitrile gloves, homogenize the soil in each bag by breaking up core chunks with your hand. If there is a lot of material in the bag, transfer it to a gallon-size Ziploc for homogenizing, then back to the quart-size bag. If the core chunks are difficult to break up with your hands, pounding them with the pestle makes this task much easier.
5. Sieve soil in each bag using 2mm sieve. Use large rubber stopper to break up soil chunks and force them thru sieve. Place soil in receiving pan back in bag and discard material greater than 2mm. You may not be able to sieve soil that is too moist. In this case, homogenize the soil as best as you can, taking care to remove as many stones as possible, along with roots, twigs, and other veg matter.
6. Tare a small aluminum weighing pan on the 3100g balance and record weight. Put subsample of sieved soil into weighing pan and re-weigh. Record weight. Put pan + soil into 60 deg C oven for 48 hours. After 48 hours, remove pan + soil from oven and let cool 30 minutes. Then weigh again on 3100g balance. Record weight. Then place pan + soil into 550 deg C muffle furnace for 2 hours. Use the one in GWC 677 (Goldwater Environmental Lab). After 2 hours, shut off furnace and open the door a crack, and leave soil to cool until the following day. Remove pan + soil from furnace and place in 60 deg C oven for 48 hours. After 48 hours, remove pan + soil from oven and let cool 30 minutes. Re-weigh and record weight. These data will be used to calculate moisture and organic matter content.
7. Take all empty core tubes and caps to the sink and wash with tap water. Scrub the insides of the core tubes with a test tube brush. This task is easier if you let the tubes and caps soak in a sweater box filled with water placed in the sink. Do not remove this box, as it is used as a sediment trap to keep the drain from clogging with soil.
8. Store processed soils in the cold room.

Soil Sample and Analyses Protocol

version 2000

Weixing Zhu

Soil Sampling

1. Samples for chemical analyses (Nitrogen, Carbon, moisture content, soil organic matter content). Sample soil 10 meter from the plot center at North, East, South, and West four directions using 1 inch diameter, 12 inch deep slam hammer soil cores. Retrieve the plastic liner from metal core and cap both ends. Use Blue cap for Bottom end and red for the upper end. Note: if sample point is paved or not safe to sample soil, move to the nearest possible position; record the sample position on the field sheet and with the GPS.
2. Samples for pH, bulk density and texture determination. One meter north from the center, use 2 inch diameter, 6 inch long slam hammer soil core to take one intact soil core for bulk density analysis. [Note: you must obtain an intact core so you can get both the soil weight and soil volume.]

Soil Processing and Analyses

A. Initial preparation and determination of soil moisture and organic matter content.

1. Combine soils collected in four cores from the same plot but separate them into 0-10 cm top-soil section and 10-30 bottom-soil section. Process and analyze two sections separately since they can be very different regarding soil chemistries. Record the weight of top soil and bottom soil (hint: you may not get a full 30 cm core, thus you should measure soil height to get the exact volume). Sieve soil through 2 mm sieve and keep sieved soil in plastic bags.
2. Weigh sub-samples of soil into aluminum pan, record both pan weight and soil weight. Dry soil in 60 C oven for 48 hours. (This was done while weighing out FW soil for KCl extraction).
3. Cool down soil in dry desiccator (~ 30 minutes), weigh Pan + Dry soil.
4. Ash dry soil in 550 C muffle furnace for 2 hours, leave the samples in the furnace overnight. Put ashed soil samples in 60 C oven for 48 hours, weigh soil as described above.

B. Processing soil for bulk density and particle analyses

1. Record the height of 2 inch diameter core and total fresh soil weight.
2. Transfer ALL soil into aluminum tray and air dry soil for a week.
3. Sieve soil through 2 mm sieve, return unpassed portion to aluminum tray and use rubber stop to crush attached soil particles, sieve soil again.
4. Weigh both sieved portion (soil) and particles can not pass the sieve (> 2 mm portion, or stone portion).
5. Weigh sub-sample of soil into aluminum weighing pan and dry at 60 C oven.
6. Record oven dry weight (60 C) as described above.
7. Put weighed pan with soil into 105 C oven for 24 hour, record soil oven weight (105 C).
8. Calculate total soil dry weight (sieved soil plus unsieved portion).
9. Calculate bulk density (g/cm3) using total soil weight and soil volume data.

C. Determining soil nitrogen (extractable NO3-N and NH4-N) content

1. For sieved soil, weigh ~ 10g fresh weight (FW) soil into 250 ml bottles, add 50 ml 2M KCl solution, shake at high speed for 1 hour on reciprocating shaker, let it settle for one hour, and filter soil slurry through ashed GF/A paper (see below for ashing method), using Falcon 7102 filter (from Fisher) unit.
2. Pour the filtrate into 60 ml bottles, acidify it with 0.2 ml 6 N HCl and refrigerate.
3. Analyze KCl solution in autoanalyzer and determine NH4 and NO3 concentrations in mg N/L.
4. Preparation of chemical solutions: 2 M KCl: Weigh 150 g KCl, dissolve in ~ 750 ml Nanopore water, bring the water level to 1 L level. Or dissolve 600 g KCl in ~ 3 L water and bring the final water level to 4 L mark. 6 N HCl: Mix 50 ml concentrated HCl with 50 ml nanopore water with caution, add acid into water, NOT vise versa! Store in 120 ml Nalgene bottle. Prepare all standards using the same extraction solution (2M KCl, acidified, for example). Add 5 ml 6N HCl to 1 L 2M KCl to get acidified KCl solution for standard preparation.

D. Calculations:

Soil % Moisture Content (calculated as g H₂O held by 100g DW soil) = (Fresh soil weight – Dry soil weight)/Dry soil weight x 100%.

% Soil organic matter = (Soil DW before ashing – DW after ashing) / Soil DW before ashing x 100%.

Dry Soil/Fresh Soil Ratio = Dry soil weight/Fresh soil weight

Dry soil weight used for KCl extraction = Fresh soil weight used for KCl extraction x Dry/Fresh ratio

Soil Extractable N (mg N/kg DW soil) = N concentrations in KCl solution (mg/L) x 50 (volume of KCl used for extraction) / Soil Dry weight used for extraction

CAP LTER particle size analysis protocol

adapted by Hannah Heavenrich 2017

This method is taken from: Gee, G.W., and J.W. Bauder 1986. Particle size analysis. p. 383-411. In: A. Klute (ed.) Methods of soil analysis, part 1. Physical and Mineralogical Methods. 2nd ed. Agron. Monogr. 9 ASA and SSSA, Madison, WI. (2ed edition). The method here will separate the sand, silt, and clay fractions. Additional hydrometer readings can be taken if greater discrimination within the size fractions is desired (see Gee and Bauder 1986).

I. Equipment and Reagents

1. Hydrometer, ASTM no. 152 H with Bouyoucos scale in g L-1.
2. Large Reciprocal Shaker
3. Metal dispersing cups (for milk shake machines)
4. 500 ml Nalgene bottles
5. Plunger for sedimentation cylinders. (A long rod with a perforated disk attached to the bottom)
6. Sedimentation cylinders with 1 L mark.
7. Amyl alcohol (only if there is excess foam after shaking)
8. Sodium metaphosphate solution, 50 g/ L-1.
9. 2 mm (no. 10) mesh sieve
10. Rolling pin and large rubber stopper (no. 10 to 14 works well)
11. Drying oven, weighing pans
12. Scale accurate to 0.1 g
13. Distilled water
14. Thermometer

II Procedure

1. Sample preparation

A. Place samples out on a bench or table to air dry for one week. It is best to break up structures in samples that are high in clay as these can become very hard upon drying.

B. When the sample is dry it may be necessary to gently crush the structures with a rubber stopper or mortal & pestal.

C. Pass the sample through a 2 mm sieve. A rubber stopper makes a good device to break up and push through soil structures. Be sure that only gentle pressure is applied, too much pressure will distort the sieve mesh.

1. Analysis

Soil Dispersion

A. Weigh a sample for analysis into a 500 mL Nalgene bottle. If the soil is fine textured, silty or clayey use about 50 g. If the soil is coarse textured use about 75 g.

B. Weigh about 10 g into a small weighing pan to determine a soil moisture correction factor. Place in oven and dry at 105^oC for 24 h. (This step has been completed for the entire 200-point survey.)

C. Add 250 mL of distilled water and 100 mL of Sodium MetaPhosphate solution to the sample in the Nalgene bottle. Place bottles in the reciprocal shaker and turn on ‘low’ setting for 24 hours.

So 50g/L * 0.1L = 5g of SMP in the solution

^As per equipment list above

D. Quantitatively transfer the suspension to a 1000 mL settling cylinder and bring the volume to 1000 mL.

5 g/L or 0.005 g/ml (aka g/cm³)

Hydrometer Measurements

A. Allow time for the mixture to equilibrate thermally (10 min is sufficient) and record temperature.

B. Insert the plunger and while holding the bottom of the cylinder, mix the solution thoroughly. Stirring should be done with rapid upstrokes and gentle downstokes such that all the sediments are dislodged from the bottom of the cylinder. Mix in this fashion for about 5 to 10 seconds, finish with two or three slow smooth strokes.

C. When mixing is completed, insert the hydrometer slowly into the solution and take a reading (at the top of the meniscus)at 0.5 min and 1 min. Record as R_0.5 and R₁. Read to the nearest 0.5 g. Rinse and dry the hydrometer between samples. Record temperature after the R₁ reading.

D. Take a hydrometer reading at 90 min and 1440 min (24 h). Record as

R₉₀ and R₁₄₄₀. Record the temperature at the time of each reading.

E. Prepare a blank solution (100 mL HMP, 900 mL distilled water, no soil) and read and the record the temperature at the same times as the soil solution above. Record as R_L0.5, R_L1, R_L90, and R_L1440.

1. Calculations

Clay Fraction

A. Use the 90 min and 1440 min readings (both R and R_L values)

B. Compute the mean particle size diameter (in m) in suspension (X) and the summation percentage (P) for the 90 and 1440 min readings. Use the equations below:

X = θt^-½

Where t is time (in minutes) and θ is the sedimentation parameter and is a function of hydrometer settling depth, solution viscosity, particle density and solution density.

Therefore: θ = Xt^-½

The sedimentation parameter, X, can be determined as follows:

X = 1000*(Bh′)^½

Where:

• B=30 *η/[g(ρs - ρl)]
• η = solution viscosity in poise, g cm-1s-1 (i.e. of HMP not just
• water (ηo))
• (viscosity of H2O† at oC *1.02125)
• η = ηo (1+4.25*[HMP]) with [HMP] in g/cm3
• η = ηo (1+4.25*[0.05])
• η = ηo 1.02125
• Where ηo = 0.01 (km/m/s) at 20°C and 0.0089(km/m/s) at 25°C
• h′ = effective hydrometer depth, cm (-0.164R+16.3)
• R is the uncorrected hydrometer reading. This assumes ASTM 152H hydrometer and standard sedimentation cylinder. (There is a formula to calculate h′ for other hydrometers and cylinders).
• g = gravitational constant, cm s-2 (980 cm s-2 )
• ρs = soil particle density, g cm-3 (2.65 g cm-3)
• ρl = solution density, g cm-3 (density of H2O† at oC*1.00315)
• ρl = ρo(1+0.630*[HMP])
• ρl = ρo(1+0.630*[0.05])
• ρl = ρo*(1.00315) Where ρo = 0.998 at 20°C and 0.997 at 25°C

^† This can be obtained form the Handbook of Chemistry and Physics

The summation percentage for a given time interval can be determined as follows:

P = (C/C_o)*100

Where:

• C = concentration of soil in suspension in g L-1 (determined C = R – RL)
• R = hydrometer reading of sample
• RL = hydrometer reading in blank (R and RL taken at each time interval)
• Co = oven dry weight of the sample

C. Compute the summation percentage at 2 um. This is determined from the equation below: (This is the percent clay)

P_2um = m ln (2/X₁₄₄₀) + P₁₄₄₀

Where:

• m = (P90 – P1440)/ln(X90/X1440)
• X1440 = mean particle diameter in suspension at 1440 min
• P1440 = summation percentage at 1440 min
• X90 = mean particle diameter in suspension at 90 min
• P1440 = summation percentage at 90 min

Sand Fraction

Compute the 50 um summation percentage using the same procedure as above, but using 0.5 and 1 min hydrometer readings. The equation for summation percentage at 50 um differs as follows: (note the bold)

P_50um = 100- (m ln (50/X₁) + P₁)

P_50um would be everything remaining in suspension smaller than 50 µm (i.e. silt + clay).

Silt Fraction

Determine the silt fraction by subtraction as follows:

% silt = 100 - (% sand + % clay)

Comments

Assuming weighing of the samples is accurate, two sources of error exist:

1. Flocculation of clays by soluble salts or gypsum during sedimentation. This can be dealt with in two ways. a) Increasing the concentration of HMP to levels high enough to maintain dispersion (be sure to use same solution in blank), and b) treatment with an acid most commonly 1 M HCl adding enough so the sample is acidified to pH 3.5 to 4.0. I would recommend increasing the concentration of HMP first since this is less troublesome than working with HCl.
2. Hydrometer reading can be a major source of error. Studies have shown that a 1% error in reading will result in a 2% error in clay calculations. (Read at the top of the meniscus since capillary action wicks the H2O up the hydrometer stem)

Soil Moisture Correction Factor

Typically, air dry soil is used for analysis as oven drying can change the nutrient content of a soil by volatilizing nutrients, or causing changes in shape of clay humus particles. Results of soil analyses are expressed on an oven dry basis as soil moisture changes with time. When analysis is performed on a soil that will have results expressed a dry weight, a soil moisture correction factor (smcf) must be calculated on a subsample.

Procedure

The weight of the sample should be about 10 grams and should be taken at the time you weigh the samples intended for analysis. The smcf should be taken from the bulk sample in such a way as to be representative of the bulk sample. This means avoid the edges of the container or stray chunks of soil which are of a differing moisture content that the bulk sample. Samples are usually dried for 24 hours at 105^oC.

After removal of the smcf sample from the drying oven, place in a desiccators for about 30 to 60 minutes. This will prevent the sample from adsorbing moisture from the air as it cools. The smcf is calculated as follows:

smcf = (dry weight/moist weight)

(where dry weight is the oven dry weight of the soil dried for 24 hours at 105 ^oC)

To convert the moist soil weight in your lab analysis to dry weight:

Dry Weight = (Moist weight)(smcf)

The formula for smcf is a modification of the formula for percent dry matter.