Agricultural Chemical Useage Barley-Sorghum Statistical Methodology

Statistical Methodology
Name of Survey: Agricultural Resource Management Survey (ARMS) Phase II: Barley and
Sorghum Production Practices and Costs Report (PPCR)
Name of Summary: Agricultural Chemical Usage, 2011 Barley and Sorghum Summary
(Access at USDA-NASS Quick Stats 2.0: http://quickstats.nass.usda.gov/. See Program: Survey,
Sector: Environmental, Group: Field Crops, Commodity: Barley or Sorghum)
Data Collection Period: October to December 2011
Target Population and Sampling Frame: The target population for the ARMS Phase II was the
official USDA farm population, within the pre-defined Program States, which is defined as “all
establishments that sold or would normally have sold at least $1,000 of agricultural products during
the year,” excluding abnormal or institutional farms.
Program States are selected to both minimize the total number of States selected and ensure at least
80 percent coverage of target-commodity acreage.
The USDA-NASS list sampling frame, including all known U.S. operations qualifying as a farm
under the USDA-NASS definition, theoretically accounting for 90 percent of total U.S. land in farms,
was the frame used to derive the sample. Control data was used to exclude abnormal or institutional
farms.
Sampling Methods: Through ARMS Phase I screening, only operations which both qualified for the
target population and reported the commodities of interest were eligible for the ARMS Phase II
sample.
From the resulting subpopulation of farms with positive acres of the target commodities, samples for
the PPCR commodities barley and sorghum were drawn through Sequential Interval Poisson
sampling - a method used primarily to control overlap within the ARMS program and overlap with
concurrent USDA-NASS surveys. This methodology ensured that (1) target sample sizes and
commodity coverage were met and (2) overlap was maximized in order to decrease the total number
of contacts.
Chemical use and production practice data for one randomly selected field of the target
commodity(s) in each sampled operation were collected through personal interview.
Sample Unit and Reporting Unit: The sample unit was the individual farm. The reporting unit was
a single, randomly selected field from each sampled farm.
Modes of Data Collection: Personal interview
Selected Terms and Definitions:
Active Ingredient: The specific pesticide ingredient which kills or controls the target pest(s) or other
target material(s), or otherwise results in the pesticide effect(s). All pesticide-use estimates in report

are at the active ingredient level; one or more active ingredients are present in known amounts in the
pesticide products reported in survey.
Estimates of active ingredient used were reported in a single unit of equivalence, per ingredient. For
salt, ester, or amine active ingredients, estimates were reported in the parent acid equivalents. For
example, the acid derivatives glyphosate isopropylamine salt and 2,4-D, 2-ethylhexyl ester were
reported in the glyphosate and 2,4-D equivalents, respectively. For copper compounds, estimates
were reported in the metallic copper equivalent.
Active Ingredient Code: A unique code assigned to each active ingredient upon registration with the
Environmental Protection Agency’s Office of Pesticide Programs, to facilitate pesticide regulation.
Area Applied, Percent: Percent of total planted acres which received one or more applications of a
specific fertilizer nutrient or pesticide active ingredient. (In Quick Stats: Treated, Measured as
Percent of Area Planted)
Avoidance: A strategy in which the detrimental effects of pests on crops are mitigated or eliminated
solely through various cultural practices. Avoidance is one of four classes of pest-management
practices for which data are included in the report.
Beneficial Insects: Insects (small invertebrate animals, mostly of arthropod classes Insecta and
Arachnida), which are collected and introduced onto crop acres because of their value in biological
control as predators on harmful insects and parasites.
Chemigation: Application of agricultural chemicals, including pesticide products, by injection into
irrigation water.
Crop Year: The period starting immediately after harvest of the previous year’s crop and ending at
harvest of the current year’s crop.
Farm: Any place from which $1,000 or more of agricultural products were produced and sold, or
normally would have been sold, during the year. Government payments are included in sales.
Fertilizer: A soil-enriching agricultural input which contains one or more plant nutrients. Data for
three primary macronutrients nitrogen (N), phosphate (P), and potash (K), and the secondary
macronutrient sulfur (S) are included in report.
Fungi: Various organisms of the kingdom Fungi, which obtain nutrients by decomposing plant or
other organic life. This pest group includes mushrooms, molds, mildews, smuts, rusts, and yeasts.
Fungal infestations have the potential to reduce crop production and/or lower the grade quality of the
host crop.

Mechanism of Action (MOA): The method or biological pathway by which the pesticide or active
ingredient kills or controls the target pest(s) or other target material(s).
Monitoring: A strategy involving the observance or detection of pests through systematic sampling,
counting, or other forms of scouting. Monitoring may include prediction of pest population levels
through the observance of environmental factors such as weather or soil and crop quality. Monitoring
is one of four classes of pest-management practices for which data are included in the report.
Nematodes: Unsegmented, parasitic worms of the phylum Nematoda. Prominent animal pest of
wheat and other field crops with the potential to be highly destructive, lowering crop production and
grade quality significantly.
Number of Applications: The average number of times a treated acre received a specific fertilizer
nutrient or pesticide active ingredient. (In Quick Stats: Applications, Measured in Number)
Pesticide: Defined by the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) as “(1) any
substance or mixture of substances intended for preventing, destroying, repelling or mitigating any
pest, (2) any substance or mixture of substances intended for use as a plant regulator, defoliant, or
desiccant, and (3) any nitrogen stabilizer…”(Title 7, U.S. Code, 136). Under FIFRA, pesticides are
registered and regulated through the Environmental Protection Agency’s Office of Pesticide
Programs. Four classes of pesticides are included in report: (1) herbicides targeting weeds, (2)
insecticides targeting insects (3) fungicides targeting fungi, and (4) other chemicals targeting all
other pests or other materials (including extraneous crop foliage).
Pheromone: A chemical substance produced by an insect which serves as a stimulus to other
individuals of the same species for one or more behavioral responses.
Prevention: A strategy in which a pest population is kept from infesting a crop or field, by taking
various preceding actions. Prevention is one of four classes of pest-management practices for which
data are included in the report.
Rate per Application: Ratio indicating pounds (lbs) of a fertilizer primary nutrient or pesticide
active ingredient applied, per single application, per planted acre. (In Quick Stats: Applications,
Measured in Lb/Acre/Application)
Rate per Crop Year: Ratio indicating pounds (lbs) of a fertilizer primary nutrient or pesticide active
ingredient applied, counting all applications per crop year, per planted acre. (In Quick Stats:
Applications, Measured in Lb/Acre/Year)
Suppression: A strategy which involves the control or reduction of existing pest populations in order
to mitigate crop damage. May include physical or biological controls, or management of resistance
build-up through pesticide rotation. Suppression is one of four classes of pest-management practices
for which data are included in the report.
Data Review and Estimation Procedures: Estimates were based on data collected, reviewed, and
verified through the cooperative efforts of the USDA-NASS Environmental and Demographics
Section and Program-State Field Offices. NASS maintains chemical use databases which contain
product recommended use ranges and active ingredient concentrations per product. These databases
are used to review pesticide product usage data and to convert pesticide product usage data to the

equivalent active ingredient levels for publication. Review and finalization of all data proceeded with
assessment of reasonableness and consistency at the record, State, and U.S. levels.
Total Applied estimates were calculated and published at the population-level using official USDANASS 2011 acreage estimates by State (published in “Crop Production – 2011 Summary” [ISSN:
1057-7823]). For this reason, all published estimates apply at the population-level defined by these
official estimates. Note that although official USDA-NASS crop acreage estimates are subject to
revision, the Total Applied estimates are not subject to revision.
Indications were published if five or more reports were received and summarized for a given variable
and if the indication was greater than or equal to one half of the pre-determined rounding unit for that
variable. Distribution and reliability measures were published if 30 or more reports were received
and summarized for a given variable.
Reliability: Estimates were subject to sampling variability; sampling variability was measured by the
coefficient of variation (cv), expressed as a percent of the estimate. Coefficients of variation were
derived and published for Percent Treated, Number of Applications, Rate per Application, and Rate
per Crop Year pesticide-usage variables. In general, a lower cv indicates a more precise estimate.
Coefficients of variation differed considerably by variable, chemical, and crop. The narrower the
numerical range of responses per variable and the larger the number of positive responses per
variable, the smaller the sampling variability. For these reasons, cv’s were generally lower for active
ingredient Rate of Application estimates and for estimates associated with the most often reported
active ingredients. (Application rates reported almost always fell within the manufacturer’s relatively
narrow recommended usage range, and a relatively large number of reports were received for the
most widely used active ingredients).
Estimates were additionally subject to non-sampling errors. Non-sampling errors result when the
target population is mis-defined through list duplication or incompleteness or sample unit data is misrecorded through mistakes in reporting, recording, or processing the data. Strict quality controls
implemented at each step of the survey and data review process minimized the occurrence and
magnitude of non-sampling errors.
Revision Policy: Estimates are final at first publication and are not subject to revision.