Test site selection

Once the targeted study regions, soil textures, space requirements, and other key aspects of study design have been determined, the search for suitable test sites 

Selection criterion Priority Basis for selection Comments 

Region A or B Site must match the climatic, soil, and agricultural conditions typical of the target crop Some crops are grovm only in certain regions (e.g., rice) while others are common to many regions (e.g., maize). Thus, selection of a test region may be restrictive or relatively flexible 

Soil properties A Soil texture (sand, silt, clay), organic matter/carbon content, and pH Stones, roots, and hardpans must be largely absent to allow representative sampling of soil profile Soil properties should appear uniform over test site Soil texture data should be available at time of site selection. Soil properties must match study purpose. This can be realistic use conditions, realistic worst-case or worst-case in terms of agrochemical mobility and persistence Must ensure that the majority of samples can be taken from the deepest sampling horizon. Information about sub-soils can be obtained from soil maps, test coring and on-site interviews 

Site topography Exclusion Must have slope 1% Site must not be susceptible to flooding Shallow water table or tile drains must not interfere with sampling These are exclusion criteria that have to be carefully determined during on-site inspection Site must be level to prevent losses of agrochemical due to surface run-off and soil erosion Site must not be susceptible to runoff from other areas higher than test site 

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Site information, including a description of the plot size, control areas, buffer zones, etc. The test site selection process which is based on factors such as pesticide use history, crop history, soil type, precipitation and irrigation history, generally precedes protocol approval ... 

Tuff, a compressed volcanic material, is the primary constituent of Yucca Mountain, near Las Vegas, Nevada, the site selected by Congress in 1987 for assessment for spent fuel disposal. An underground laboratory, to consist of many kilometers of tunnels and test rooms, is to be cut into the mountain with special boring equipment to determine if the site is suitable for a repository. 

It has been traditional to subject workers to higher risks than the public, (a) Write a short discussion of the equities of this practice with consideration for the fact the worker may leave employment that imposed a long term risk, (b) The Nevada Test Site has been selected as a possible location for a high level waste repository. For purposes of the risk assessment, the workers in the repository will be treated as workers with subsequent higher allowable risk. There are many other workers at NTS. Discuss whether these should be treated as workers or public, (c) If they are treated... 

Team responsibilities Define PSM criteria and goals for Company X evaluate current PSM status develop a plan to build on what s in place and address gaps develop specific PSM systems select a test site and install a pilot system measure and monitor its progress refine systems as needed. [Limits]... 

If the answer in both cases is "yes," then consider the locd climate. Local cooperation—or lack of it—may he the single most important determinant of site selection, since without it you cannot field a valid test. However if you have kept facility managers informed or involved as the PSM process has gone forward, you should have some ideas about which of them would be par-ticulariy enthusiastic—or otherwise. In addition, having identified site-specific benefits may help you win the support of a manager who might otherwise be reluctant to participate. 

We have selected the Manwood plant as the test site, in consultation with Facility Manager Ray Leonard, who will play a key role in overseeing the installation. All Manwood employees will participate, either directly or indirectly, and we will actively solicit their feedback about the system based on their experience with it. 

The following considerations are critical in the selection and preparation of residue study test sites ... 

Trial sites should be selected in the growing areas of the target crop, from at least two different areas. Test sites must be far enough apart to avoid cross-contamination. 

Test sites are selected from areas with different environmental and cultural conditions that might affect the levels of pesticide residues (e.g., temperature, soil characteristics, planting patterns). 

The PI must be judicious in the selection of the test site in order to maximize the chance of a successful trial and in meeting the study objectives. 

Pesticides used on crops grown on the test site in previous seasons may also have an impact on the outcome of a field residue trial. Carryover of prior pesticide applications could contaminate samples in a new trial, complicate the growth of the crop in a trial, or cause interference with procedures in the analytical laboratory. For this reason, an accurate history of what has transpired at the potential test site must be obtained before the trial is actually installed. The protocol should identify any chemicals of concern. If questions arise when the history is obtained, they should be reviewed with the Study Director prior to proceeding with the test site. In most annual crop trials, this will not be a significant issue owing to crop rotations in the normal production practices, because the use of short residual pesticides and different chemical classes is often required for each respective crop in the rotation. However, in many perennial crops (tree, vines, alfalfa, etc.) and monoculture row crops (cotton, sugarcane, etc.), the crop pesticide history will play a significant role in trial site selection. 

Another important test location factor is the availability of water for irrigation and for preparation of the spray solution. The use of culinary water sources (either private or public water sources intended for human consumption) or groundwater (from wells) is usually less problematic than using water from surface sources (rivers, lakes, or canals). If surface water is used for the study, care must be taken to ensure that farm production activities upstream from the plot area have not contaminated the water supply with pesticides that could contaminate the plot area. Careful site selection will help avoid problems from the water available at the site. 

Whatever the case, the ability to irrigate test plots is an important consideration during field site selection. Sprinkler irrigation is preferred. Flood and furrow irrigation should be avoided since they may disturb surface residues, resulting in uneven residue distribution and/or inadvertent agrochemical loss from the study plots. Recommended irrigation practices are discussed in more detail in Section 3.3.8. 

Each of the five main steps in field conduct (site selection, test plot layout, test substance application, sample collection, and sample storage/handling) is addressed below. 

Ideally, when small mammals are being evaluated, the treated area beyond the test site should be large enough that any recruitment of study species to the test site will be from a treated area. It is not possible to cover this recruitment area for most bird species and it is often impractical for small rodents, but should be considered. Owing to abundance, home range and recruitment dynamics, small passerines and small rodents are often selected as test species. 

Furthermore, brackish water bodies that are present in many aquifers could be used after desalination. Different test sites were selected for GABARDINE project,... 

Prior to the advent of DDT, no highly successful chemical control of tsetse flies had been accomplished. In 1945 duToit, Graf, and Theiler of the Onderstepoorte Staff began their investigations on aircraft-distributed DDT for the control of adult tsetses. The site selected was a belt 30 square miles, comprising the Mkuzi Reserve in Northern Zululand, an area well populated with G. pallidipes. In the preliminary tests a 5% solution of DDT in furnace oil was applied as a spray at the... 

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