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Methods for Experiment 003 -

Animal Sampling Methods

Small mammal trapping in E003 was the same as that in E001.

Burning LTER Plots

All of the burning done within LTER experiments at Cedar Creek Natural History Area are done in late April or early May. Burn permits are issued to Cedar Creek Natural History Area for this time, and the following areas within Cedar Creek, by the Department of Natural Resources (headquarters in Cambridge, MN). In all cases, several people are on hand to help contain the fire. Tools used are "flappers", shovels and hand-pumped, portable water spray-cans. Drip torches containing a mixture of 1/3 gasoline and 2/3 diesel are used to start the fires. A truck carrying a high pressure water sprayer hooked up to a 125 gallon tank of water is always nearby. After the fires are burned out, any remaining hotspots are extinguished or moved to the center of the burned area to insure the prevention of wildfires.

125 gallon water tank and Minnesota Warmer Co. model KW125-7-10 utility sprayer.

Burning Methods

Field D is within burn compartment #6 (106). This field was burned 2 years out of every three. For a description of burning methods, see E015.

Fertilization Treatments

Each of the 8 treatment levels in this experiment contains a single nutrient. There is also a control which receives no nutrients. The treatments are assigned a capital letter A through I or digits 1 through 9.

Treatment CodeNutrient Added
A 20 g/m2 NH4NO3
B 35 g/m2 NaH2PO4-H2O + 35 g/m2 Na2HPO4
C 87 g/m2 K2SO4
D 75 g/m2 CaCO3
E 60 g/m2 MgSO4
F 71 g/m2 Na2SO4
G 60 ml/m2 trace metal sand*
H 4 gal/m2/week H2O
I no nutrients added
 

*see nutradd.doc for documentation The plots are 4 m2 in area.

Field Operations: Burning

Field D is within burn compartment #6 (106). This field was burned 2 years out of every three. On May 5, 1995 a wild fire burned all of the plots in experiment 3 in field B

Field Operations: Fencing

The plots in experiment 003 were enclosed by a fence to exclude mammalian herbivores. Galvanized welded-wire hardware cloth with 6mm x 6mm openings was buried to a depth of 84cm. Additional hardware cloth extended 60cm above the ground, and poultry netting extended to 1.8m above the ground.

Field Operations: Fertilization

Fertilizer was mixed and spread by hand twice a year, once in early May and once in late June. Each plot got the fertilizer mixture specified by its fertilizer treatment code. For a list of fertilizer treatments for each plot.

Field Operations: Mammal Trapping

Small mammals were trapped as often as possible to keep the resident population low. A list of the number and kind of mammals taken from each field is in the small mammal documentation file. Pocket gophers were trapped out of the fields as soon as they appeared. Gopher mounds weare then removed and buried vegetation was unburied.

Field Operations: Watering

Treatment "H" plots got 24 gallons of water per week between May 1 and mid-September. This was at a rate of 4 gallons of water per meter squared per week. There were four of these plots in each of the four fields.

Light Penetration

Light meter readings for E003 were taken the same way as in E001. However, since these plots were more narrow, the position of the light readings was usually different (distance from the side of the plot).

Light Penetration Measurements Methods

From 1982 to 1988, light meter readings were taken using a Li-Cor, Inc. Integrating Quantum/Radiometer/Photometer, model LI-188B. Two people were needed to take light readings with this system. One would hold the control box and record data and the other would hold the light sensor. The batteries would be checked before starting each session. If the batteries were OK, they would proceed to take readings. The sensor was connected to the control box by a relatively short cord, so the two people taking readings were required to stay close together. When taking readings, it was necessary to get a range value for each light value entered. If the integrating time of 1 second was not sufficient, it was increased to 10 seconds. This was also recorded.

In 1989, two new light meters were acquired. These are SF Sunfleck Ceptometers, model SF-40 (40cm probe). They were purchased from Decagon Devices, Inc., P.O. Box 835, Pullman, WA 99163. One person can easily handle a ceptometer alone. This makes is possible for three people to get the readings done more quickly and easily. One person records data while the other two take readings from the plots simultaneously. No range values are needed. To take readings a person needs to select function #1 (PAR readings), position the probe (see below) and press ``A' (read value). More than one reading can be taken and then averaged by pressing a certain sequence of letters (A, A, B, B, A).

Measurements are taken within a 4 hour period, 2 hours on either side of solar noon. (Solar noon is half way between sunrise and sunset; it is not 1200 hours). Solar noon is at 1315 hours, Central Daylight Time. Samples are taken between 1115 hours and 1515 hours. Measurements are not taken when the plot being sampled is shaded. Light readings are done when the sky is clear, whenever possible. If a cloud passes over the plot being sampled, assistants wait for the cloud to pass before taking the readings. If the sky is mostly cloudy, light meter readings are not taken.

Two measurements are taken in each plot. Each measurement consists of one reading above the vegetation and a second reading at ground level. Both values are taken to get the percent of sunlight above the vegetation that reaches ground level. In taking the above vegetation reading, the sensor must be kept level, held high above all vegetation, kept out of the shade (of plants and people) and it must be clean. When taking the below vegetation reading, at ground level, the sensor must be kept level, out of the soil and out of the shade created by people.

In 1991, light meter readings were only taken in E026 and E055. Light profiles were taken using an A-shaped frame made of aluminum. Wires were strung across the frame at 10cm intervals. The frame was placed over the subplot being metered. A reading was taken over the top of the frame, and then at each 10cm level, by placing the light meter across the wires, starting at 90cm above the ground. Readings were taken every 10cm down the frame and again at ground level.
Light Data Transformations:
Light readings are transformed to obtain percent light penetration which represents the percent of light above the vegetation that reaches the ground surface. In cases where the experiment involves shading, another variable is computed to reflect the percent of sun light that reaches above the canopy. This variable is called light available. In the case of absence of artificial shades, the latter is set to 1.

percent light penetration = ( Light below canopy / Light above canopy ).

percent light available = ( Light below shade / Light above shade ).

Treatment layout : trmte03

Field Identification Experiment Number Plot Number Treatment
A 3 1 3 3
A 3 2 2 2
A 3 3 6 6
A 3 4 1 1
A 3 5 8 8
A 3 6 7 7
A 3 7 9 9
A 3 8 4 4
A 3 9 5 5
A 3 10 1 1
A 3 11 8 8
A 3 12 7 7
A 3 13 6 6
A 3 14 3 3
A 3 15 5 5
A 3 16 4 4
A 3 17 9 9
A 3 18 2 2
A 3 19 2 2
A 3 20 8 8
A 3 21 9 9
A 3 22 3 3
A 3 23 4 4
A 3 24 1 1
A 3 25 5 5
A 3 26 6 6
A 3 27 7 7
A 3 28 1 1
A 3 29 2 2
A 3 30 9 9
A 3 31 3 3
A 3 32 5 5
A 3 33 7 7
A 3 34 4 4
A 3 35 6 6
A 3 36 8 8
B 3 1 5 5
B 3 2 4 4
B 3 3 3 3
B 3 4 7 7
B 3 5 2 2
B 3 6 9 9
B 3 7 8 8
B 3 8 6 6
B 3 9 1 1
B 3 10 9 9
B 3 11 6 6
B 3 12 8 8
B 3 13 7 7
B 3 14 5 5
B 3 15 4 4
B 3 16 3 3
B 3 17 1 1
B 3 18 2 2
B 3 19 2 2
B 3 20 8 8
B 3 21 7 7
B 3 22 5 5
B 3 23 9 9
B 3 24 4 4
B 3 25 6 6
B 3 26 3 3
B 3 27 1 1
B 3 28 3 3
B 3 29 9 9
B 3 30 4 4
B 3 31 6 6
B 3 32 7 7
B 3 33 5 5
B 3 34 2 2
B 3 35 8 8
B 3 36 1 1
C 3 1 2 2
C 3 2 6 6
C 3 3 9 9
C 3 4 8 8
C 3 5 1 1
C 3 6 3 3
C 3 7 4 4
C 3 8 7 7
C 3 9 5 5
C 3 10 3 3
C 3 11 1 1
C 3 12 8 8
C 3 13 6 6
C 3 14 5 5
C 3 15 9 9
C 3 16 4 4
C 3 17 7 7
C 3 18 2 2
C 3 19 4 4
C 3 20 8 8
C 3 21 9 9
C 3 22 6 6
C 3 23 2 2
C 3 24 7 7
C 3 25 3 3
C 3 26 1 1
C 3 27 5 5
C 3 28 4 4
C 3 29 6 6
C 3 30 3 3
C 3 31 1 1
C 3 32 7 7
C 3 33 5 5
C 3 34 9 9
C 3 35 2 2
C 3 36 8 8
D 3 1 8 8
D 3 2 4 4
D 3 3 7 7
D 3 4 9 9
D 3 5 6 6
D 3 6 5 5
D 3 7 3 3
D 3 8 2 2
D 3 9 1 1
D 3 10 6 6
D 3 11 3 3
D 3 12 2 2
D 3 13 1 1
D 3 14 9 9
D 3 15 8 8
D 3 16 5 5
D 3 17 4 4
D 3 18 7 7
D 3 19 8 8
D 3 20 6 6
D 3 21 5 5
D 3 22 1 1
D 3 23 2 2
D 3 24 3 3
D 3 25 9 9
D 3 26 7 7
D 3 27 4 4
D 3 28 3 3
D 3 29 1 1
D 3 30 9 9
D 3 31 8 8
D 3 32 7 7
D 3 33 5 5
D 3 34 6 6
D 3 35 2 2
D 3 36 4 4
 

Vegetation Sampling Methods

E003 was in fields A, B, C and D. Vegetation sampling was done the same way in each of the four fields. These plots were more narrow than those in experiments E001 and E002, but the clip strip was still 10cm x 3m long. This experiment was not clipped every year, nor was it clipped on a regular schedule.

Each year, the sample strip was located in a different place.

Documentation on where the strips were located for each year can be found in the sampling maps.

Vegetation Sampling in Field A

Clip strips were 10cm wide and 3m long.

1982: Clipped at ?
1983: Clipped at ?
1984: Clipped 50cm from right side
1985: Not clipped
1986: Clipped 30-40cm from left side
1987: Not clipped
1988: Clipped 45-55cm = middle
1989: Clipped 35-45cm from left side
1990: Not clipped
1991: Clipped 25-35cm from left side
1992: not clipped

Sampling Problems in Field A:

1982: ?
1983: ?
1984: A-3-28 reclipped at 25cm from right side
This plot was originally left out in the field, so it was resampled.
1986: none
1988: A-3-22 reclipped at 25-35cm from right side
A-3-24 reclipped at 25-35cm from right side
These two plots were reclipped due to initially being sorted together.
1989: none
1991: A-3-3 reclipped at 25-35cm from right side
A-3-13 reclipped at 25-35cm from right side
These two plots were reclipped due to initially being sorted together.

Other Notes:
Field A was clipped in 1982 and 1983, but there is no documentation as to where in the plots it was clipped.

Vegetation Sampling in Field B

Clip strips were 10cm wide and 3m long.

1982: Clipped at ?
1983: Clipped at ?
1984: Clipped 50cm from right side
1985: Not clipped
1986: Clipped 30-40cm from left side
1987: Not clipped
1988: Clipped 45-55cm = middle
1989: Clipped 35-45cm from left side
1990: Not clipped
1991: Clipped 25-35cm from left side
1992: Not clipped

Sampling Problems in Field B:

1982: ?
1983: ?
1984: none
1986: none
1988: none
1989: none
1991: none

Other Notes:
Field B was clipped in 1982 and 1983, but there is no documentation as to where in the plots it was clipped.

Vegetation Sampling in Field C

Clip strips were 10cm wide and 3m long.

1982: Clipped at ?
1983: Clipped at ?
1984: Clipped 50cm from right side
1985: Not clipped
1986: Not clipped
1987: Not clipped
1988: Clipped at 45-55cm = middle
1989: Clipped 35-45cm from left side
1990: Not clipped
1991: Clipped 25-35cm from left side
1992: Not clipped

Sampling Problems in Field C:

1982: ?
1983: ?
1984: C-3-19 clipped at 50cm from left side
1988: none
1989: none
1991: none

Other Notes:
Field C was clipped in 1982 and 1983, but there is no documentation as to where in the plots it was clipped.

Vegetation Sampling in Field D

Clip strips were 10cm wide and 3m long.

1982: Clipped at ?
1983: Clipped at ?
1984: Clipped 35cm from right side
1985: Not clipped
1986: Not clipped
1987: Not clipped
1988: Clipped at 45-55cm = middle
1989: Clipped 35-45cm from left side
1990: Not clipped
1991: Clipped 25-35cm from left side
1992: Not clipped

Sampling Problems in Field D:

1982: ?
1983: ?
1984: none
1988: D-3-36 reclipped at 25-35cm from right side
1989: none
1991: none

Other Notes:
Field D was clipped in 1982 and 1983, but there is no documentation as to where in the plots it was clipped.

Watering Methods

This experiment was in four fields A, B, C and D. There were four plots in each field that get treatment "H". Treatment "H" plots received 24 gallons of water per week between May 1 and mid-September. The water was brought out to the fields in a 200 gallon water tank. The tank was loaded on the back of a 3/4 ton pickup truck and filled with water. Only two fields could be done before the tank needed to be refilled. The truck was parked outside the fenced area as close to the E003 plots as possible. Two full length garden hoses were then laid out to the first plot to be watered. A water pump in the pickup truck was then started. This pumped the water from the tank to the plots through the hoses. The water was distributed evenly over the entire plot using a hand held sprinkler nozzle on the end of the hose. Each plot was watered from 6-10 minutes depending on the water pressure, giving each plot 24 gallons. E003 plots were not watered while it was raining or within 24 hours of a rainfall that was greater than 0.25 inches.