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University of Minnesota
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Methods for Experiment 005 -

Field Operations: Burning

Starting in 1989, two sections in each macroplot were burned in fields B and C. Each macroplot is divided into 5 sections. In each macroplot, the center section and 1 section on either the east or west side of it were burned. For a list of burn treatments for each plot, see files trmte04. See E004 for Burn Doc for information on wildfire in 1995.

Field Operations: Fencing and Herbivore Exclusion

There are 4 fence exclosures, each designed to exclude a specific group of herbivores. In addition there is a fence to exclude all 4 groups, a fence that excludes no herbivores to measure fence effects, and a plot with no fence as a control. Exclosures are 2m x 4m and are located in macroplot subsections 3 and 8. Herbivore treatments are randomly placed in the grid. To exclude all herbivores, a deep fence, Sevin and Diazanon were used. A shallow fence was used to exclude voles. Sevin was used to exclude foliage-feeding insects and Diazanon was used to exclude belowground invertebrates.

Field Operations: Fertilization

Fertilizer is mixed and spread by hand twice a year, once in early May and once in late June. Each plot gets the fertilizer mixture specified by its fertilizer treatment code. For a list of fertilizer treatments for each plot, see file trmte05.

Light Penetration

Light meter readings for E005 were taken in 1985 in the same way as in E001 except gopher mounds were ignored. Light meter readings were taken in the same positions in all plots, regardless of the presence of gopher mounds.

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 ).

Microplot Fertilization Treatments

Some changes and/or additions occur from year to year for some experiments. These changes are listed below. Unless specific experiments are mentioned, these differences apply to all experiments in a category. In 1982, 30ml of each stock solution was combined with 16.8g citric acid, brought to a total volume of 1 liter, and autoclaved to dissolve. 1.5ml of this solution was added to 30ml of silica sand, mixed and dried. In 1983, 60ml of each stock solution was combined with 25g of EDTA brought to 1 liter, and autoclaved to dissolve. 1ml of this solution was added to 10ml of sand and added to each plot. In 1984, 60ml of each stock solution was combined with 25g of citric acid and brought to 1 liter. In 1985, the first fertilization for experiments 1 and 2, Treatment F received an extra 23 g/m2 of CaCO3 Treatment G received an extra 118.5 g/m2 of CaCO3 Treatment H received an extra 132.5 g/m2 of CaCO3 In 1985, between fertilizations for experiments 1 and 2, Treatment G received 137.5 g/m2 of CaCO3 Treatment H received 206.25 g/m2 of CaCO3 In 1985, the second fertilization for experiments 1 and 2, Treatment F received an extra 23.0 g/m2 of CaCO3 Treatment G received an extra 252.7 g/m2 of CaCO3 Treatment H received an extra 441.1 g/m2 of CaCO3 In 1985, the first fertilization for experiment 4, Treatment E received no CaCO3 Treatment G received an extra 45.5 g/m2 of CaCO3 In 1985, both fertilizations for experiments 8, 9, and 11, Treatment F received an extra 23 g/m2 of CaCO3 Treatment G received an extra 43.5 g/m2 of CaCO3 Treatment H received an extra 57.5 g/m2 of CaCO3 In 1989, lime was added to adjust pH to the following treatments in the spring: Quantities of lime stone (g/plot):

Experiment 1 Experiment 2
Treatment Field A Field B Field C Field D Field A Field B Field C
A 00 0 200 0 0 0
B 0 0 320 200 0 0 320
C 0 0 320 200 0 0 0
D 850 320 320 200 0 800 320
E 1000 850 1000 200 800 0 600
F 1300 1200 1900 200 800 0 1200
G 1300 320 320 200 500 0 500
H 2100 1600 1000 200 600 0 1600
I 0 0 0 0 0 0 0
 

In the fall of 1989, each plot receiving treatments B, C, D, E, F, G and H in field D of experiment 1, received 1067g of lime to adjust pH

Microplot Fertilization Treatments

The "microplot" fertilization treatments are used in experiments 1, 2, 4, 8, 9, 11, 23, 25, and 52. Experiments 5, 6, 28, 36,53,97, 98 and 100 are conducted within plots that are fertilized and should be treated as part of the fertilized plot. There are nine treatment levels, assigned a letter A through I. This is also equivalent to the numeric labels 1 to 9. Treatment levels A through H differ in the amount of NH4NO3 added. Treatment I is a true control and receives no nutrients. The nutrients are applied twice a year, once in early May and once in late June. An exception is experiment 25 where time of application is experimentally manipulated. Not all experiments use all possible treatments. Nutrients are given in g/m2 for each fertilization; plot area and treatments used follow the nutrient lists. Treatment A to H receive the following base nutrients:

Rate Volume Element
10 g/m2 150 ml P2O5 (0-46-0)
10 g/m2 150 ml K2O (0-0-61)
20 g/m2 200 ml CaCO3 (lime)
15m2 200 ml MgSO4 (Epsom Salts)
0.0625 ml/m2 trace mineral solution in 1 ml to 10 ml sand
 

The description for making trace mineral sand is at the end of this section. The amount of NH4NO3 fertilizer added at the different treatment levels is:

Treatment Rate Volume
A 0.0 g/m2 0 ml
B 1.5 g/m2 25 ml
C 3.0 g/m2 50 ml
D 5.0 g/m2 90 ml
E 8.0 g/m2 140 ml
F 14.0 g/m2 250 ml
G 25.0 g/m2 445 ml
H 40.0 g/m2 710 ml
I 0.0 g/m2 0 ml
 

These rates are added twice a year. Actual annual N addition is calculated as: 0.34%N * rate (g/m2) * 2 times/year The trace mineral stock solutions are made by adding the following grams of reagent to 1000 ml of water: CuSO4*5H2O 9.8 g ZnSO4*7H2O 22.0 g or ZnCl2 10.5 g CoCl2*6H2O 10.0 g MnCl2*4H2O 180.0 g Na2MoO4*2H2O 6.3 g H3BO3 6.0 g The trace metal solution is made by combining 120ml of each stock solution, adding 67.2g of citric acid dissolved in deionized water and adding deionized water to bring the volume to a total of 2 liters. The working solution is then autoclaved to chelate the trace metals. The size of the plots and treatments used for each experiment are:

Experiment Treatments Plot size (m2)
Experiment 1 except Field D A thru I 16
Experiment 1 Field D A thru I 6
Experiment 2 A thru I 16
Experiment 4 E, G, I 1000
Experiment 8 C, F, H, I 16
Experiment 9 C, F, H, I 16
Experiment 11 E, G, I 16
Experiment 24 E, G, I 16
Experiment 25 E, G, I 5.25
Experiment 52 A, C, F, G 25
 

Sampling for A005

n 1984, A005 was sampled. Plots 3, 4, 6, 7, 8, 9, and 10 were clipped, 25cm from the tagged side. Plots 1 and 2 were clipped 50cm from the left side. In 1985, A005 was clipped 50cm from the tagged side. The clip strips were 10cm wide and 3m long.

Sampling for B005

In 1982, B005 was sampled, but there is no documentation as to where in the plots it was clipped. In 1985, B005 was clipped 50cm from the tagged side. The clip strips were 10cm wide and 3m long.

Sampling for C005

In 1982, C005 was sampled, but there is no documentation as to where in the plots it was clipped. In 1985, C005 was clipped 50cm from the tagged side. The clip strips were 10cm wide and 3m long.

Treatment layout : trmte05

Additional notes: Exclosure treatment codes: 1=All excluded 2=Voles excluded 3=Foliage-feeding insects excluded 4=Gophers excluded 5=Fenced control 6=Control-no treatment 7=Below-ground invertebrates excluded 8=Control-no treatment

Field Identification Experiment Number Plot Number Enclosure Treatment Nitrogen Treatment Ammonium Nitrate (34-0-0) addition (g/m2/yr)
A51190
A51290
A51390
A51490
A51590
A51690
A51790
A51890
A521750
A522750
A523750
A524750
A525750
A526750
A527750
A528750
A531516
A532516
A533516
A534516
A535516
A536516
A537516
A538516
A541750
A542750
A543750
A544750
A545750
A546750
A547750
A548750
A56190
A56290
A56390
A56490
A56590
A56690
A56790
A56890
A571750
A572750
A573750
A574750
A575750
A576750
A577750
A578750
A581516
A582516
A583516
A584516
A585516
A586516
A587516
A588516
A59190
A59290
A59390
A59490
A59590
A59690
A59790
A59890
A5101516
A5102516
A5103516
A5104516
A5105516
A5106516
A5107516
A5108516
B511516
B512516
B513516
B514516
B515516
B516516
B517516
B518516
B52190
B52290
B52390
B52490
B52590
B52690
B52790
B52890
B53190
B53290
B53390
B53490
B53590
B53690
B53790
B53890
B541750
B542750
B543750
B544750
B545750
B546750
B547750
B548750
B55190
B55290
B55390
B55490
B55590
B55690
B55790
B55890
B571750
B572750
B573750
B574750
B575750
B576750
B577750
B578750
B581516
B582516
B583516
B584516
B585516
B586516
B587516
B588516
B591516
B592516
B593516
B594516
B595516
B596516
B597516
B598516
B5101750
B5102750
B5103750
B5104750
B5105750
B5106750
B5107750
B5108750
C511516
C512516
C513516
C514516
C515516
C516516
C517516
C521750
C522750
C523750
C524750
C525750
C526750
C527750
C53190
C53290
C53390
C53490
C53590
C53690
C53790
C541750
C542750
C543750
C544750
C545750
C546750
C547750
C55190
C55290
C55390
C55490
C55590
C55690
C55790
C561516
C562516
C563516
C564516
C565516
C566516
C567516
 

Vegetation Sampling Methods

E005 is in fields A, B and C. Vegetation sampling was done the same way in each of the three fields.
Sample size was 0.1m x 3m.