Establishing 

Noxious Weed

Demonstration

Plots

By Celestine Duncan

Weed Management Services

Helena, Montana

This Resource Note is adapted from

the December 2000 issue of TechLine,

(published by Ag West Communications.) summarizing several studies

and successful post–fire management

programs.

Used with permission of the 1999

California Exotic Pest Plant Council

Proceedings.

The purpose of this article is to

outline procedures for designing demonstration plots on noxious

weeds. These plots can be utilized to

answer questions you or the public

may have regarding effectiveness of

various management tools such as

herbicides, physical, mechanical, or

biological treatments. These plots

can also be used during tours and

meetings to show the public and

others how different management

techniques compare under “field”

conditions.

Establish Objectives:

The most important step in establishing any demonstration plot is to

develop a clear objective for the

study, such as “Compare the effectiveness of various biological and

mechanical treatments on cover and

density of spotted knapweed.”

In developing your study objectives, you should contact Extension Weed Specialists to determine

whether studies have been completed

that address your questions, or if

there are demonstration plots

already established in your area.

You may want to modify your study

design and objectives based on previously conducted or on-going

research.

Site Location:

Once your objectives are established, you need to find a location

that best fits the study. The site

should be selected based on the

following criteria:

1. Sites that will be utilized for

“demonstration” purposes should be

easily accessible to the public.

2. The demonstration area should be

located no more than a 30-minute

drive from a community or convenient meeting location (such as FS

or BLM district office).

3. Weed cover and density should be

uniform in the plot area to compare

various treatments.

4. The site should be large enough so

various treatments can be applied

adjacent to each other.

5. The site should be typical of areas

that are infested with the target

weed.

Plot Size:

Plot size is dependent on the objectives of the study, treatments that are

being applied, size of the application

equipment, and sampling methods.

In general, individual plots for

demonstration purposes of herbicide,

mechanical, or manual treatments

should be about 20 by 30 feet

with a minimum plot size of 10

by 25 feet. Buffer zones of 3 to 4

feet may be needed between treatments to minimize seed contamination, reduce the potential for drift

between plots, and allow for good

visual observation of the plot without

walking through treatments.

Plot Arrangement:

Demonstration plots should be

arranged so that various treatments

can be viewed easily and treatments

are on similar slope, aspect, soil, and

vegetation type. Be sure to include

an untreated control plot with the

treated plots so that visual comparisons or quantitative measurements

can be determined. Untreated plots

should be located upwind and upslope from treated plots to minimize

possibility of drift or movement of

seed from other plot treatments.

Plot Identification:

This is critical once the site is located.

Individual plot corners should be

marked with wooden or metal

stakes. Metal rebar can be buried

level with the ground on the four

outside corners to ensure that the

plot area will be permanently

marked (metal detectors can be utilized to find the corners if necessary). Treatments should be marked

on metal tags and placed on the left

corner stake of each plot (see diagram). If possible, the distance from

two plot corners to a permanent fixture (telephone pole, building corner, section corner, fence line, etc)

should be recorded in a field notebook in case plot stakes are destroyed

by wildlife, livestock, or fire. On

sites that have high livestock or

wildlife use, metal pins and large

metal washers can be buried flush

with the ground to mark plot corners. This will minimize disturbance

by animals, but it also makes the

markers difficult to locate in tall

vegetation.

Application Equipment:

Use commercial application equipment or equipment that simulates

commercial application, such as

experimental plot sprayers for herbicide treatments. Seed drills or herbicide sprayers must be calibrated

prior to application so that the rate

that is being applied is accurate. In

most situations, single nozzle backpack sprayers should not be used for

applying herbicides to demonstration

NO. 55 DATE 10/31/01

Range

Forestry
Sample Demonstration Plot Diagram

Treatment 1 Treatment 2 Treatment 3 Treatment 4 Buffer Buffer Buffer

20'

30

Plot identification number and treatment name

Plot boundary marker

Measurement to permanent fixture (fence, telephone pole, etc)

plots because of difficulty in

maintaining a consistent pattern

throughout the plot area. Proper

application of all treatments is

essential to maintaining integrity of

the study.

Record Keeping:

Accurate records must be kept during all aspects of the study. This

includes site location and directions

to the site, plot layout and design,

and application and monitoring

information. A treatment list

including application rates, date of

application, and conditions during

application are essential to the

study. Application records that must

be recorded include:

1. Name of applicator

2. Date and time of day application

was made

3. Make and model of application

equipment

4. Equipment calibration records

(speed traveled, output)

5. Total output in gallons per acre

for herbicide application equipment

6. Application rates (this includes

herbicide rate, number of biological

agents released, number of people

hand pulling, seeding rates, etc).

Environmental conditions to

record at application include:

1. Air temperature

2. Soil temperature [at 3 or 4 inches]

3. Wind speed and direction

4. Percent relative humidity

5. Percent cloud cover

6. Soil moisture (dry, moist, or wet)

7. Soil texture (series name if possible), slope, and aspect

8. Soil organic matter and pH if

relevant to the study

9. Date to first precipitation event

10. Vegetative growth stage of key

species including the target weed

Monitoring:

Monitoring results is critical to the

success of demonstration areas.

Visual percent control (compared to

untreated plots), density, cover,

and/or frequency are often used to

evaluate differences between various

treatments. Data collection should

be consistent between years, and for

most noxious weed species should

be conducted for at least 3 years to

determine long-term effectiveness of

treatments.

Summary:

Demonstration plots are an excellent

method to evaluate new weed management methods on a small scale to

determine their application to your

area. They also serve as an effective

tool for educating the public about

various management methods. However, their success is based on the

accuracy with which the treatments

are applied and annual monitoring of

results. Be sure to maintain accurate

detailed records so that someone else

can continue monitoring efforts if

you move or transfer to another

position.

Range

Resource Notes are intended to be early

announcements of technical and informational topics for

Bureau of Land Management personnel and some of their customers.

Information in this Resource Note is based on the opinion and

experience of the author and has not been peer-reviewed. Conclusions

and opinions expressed herein do not

necessarily represent those of BLM. Use of trade names does not

imply U.S. Government endorsement of commercial products.

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