United States Environmental Protection Agency Environmental Monitoring Systems Laboratory Las Vegas, NV 89193-3478 Research and Development EPA/620/SR-94/014 June 1994 Project Summary Environmental Monitoring and Assessment Program: Agroecosystem Pilot Field Program Report- 1992 C. Lee Campbell, Jeff M. Bay, Anne S. Hellkamp, George R. Hess, Michael J. Munster, Karen E. Nauman, Deborah A. Neher, Gail L. Olsen, Steven L. Peck, Brian A. Schumacher, Kurex Sidik, Mark B. Tooley, and David W. Turner The Agroecosystem Resource Group (ARG) of the Environmental Monitoring and Assessment Program (EMAP) has developed a five-year strategy for the development, evaluation, and imple- mentation of a suite of indicators for monitoring the status and trends of agroecosystem condition on a regional and national basis. The five-year pe- riod includes time to test concepts re- lating to design, indicators, quality as- surance, logistics, information manage- ment, data analysis, assessment, and reporting at the pilot and demonstra- tion program stages. A primary em- phasis is on the development of close working relations between personnel from the U.S. Environmental Protection Agency (EPA), the U.S. Department of Agriculture's (USDA) Agricultural Re- search Service (ARS) and National Ag- ricultural Statistics Service (NASS) and the ARG. The 1992 Pilot Field Program in North Carolina evaluated all aspects of the monitoring program for a se- lected suite of indicators. The Pilot was conducted over an area large enough to provide reliable answers to ques- tions concerning the operation of the monitoring program but small enough to be physically and fiscally manage- able. Results will be used to plan for a regional demonstration project and to address specific concerns of applying the program indicators in a different geographic area of the country. In ad- dition, results will assist the ARG in establishing an acceptable sampling design, set of core indicators, logis- tics, quality assurance and information management protocols, and an assess- ment framework for use in monitoring the status, trends, and condition of the nation's agroecological resources. This Project Summary was developed by EPA's Environmental Monitoring Systems Laboratory, Las Vegas, NV, to announce key findings of the research project that is fully documented in a separate report of the same title (see ordering information at back). ti Introduction In 1992 a Pilot Field Program was con- ducted in North Carolina by members of the Environmental Monitoring and Assess- ment Program's (EMAP) Agroecosystem Resource Group (ARG). EMAP originated within the Office of Research and Devel- opment (ORD) of the U.S. Environmental Protection Agency (EPA) and is now an interagency, interdisciplinary initiative to monitor the condition of the nation's eco- logical resources. The U.S. Department of Agriculture's (USDA) Agricultural Research Service (ARS) provides technical leader- ship for the Agroecosystem component, one of eight resource categories within EMAP. The ARG cooperated with the USDA's National Agricultural Statistics Service (NASS) in the development and data collection aspects of the 1992 Pilot. The three principal agencies cooperated Printed on Recycled Paper ------- in the Pilot as the first developmental step toward the implementation of a plan for monitoring the ecological condition of agroocosystems in the United States. The mission of the ARG is to develop and implement a program that will, in the long term, monitor and assess the condition and extent of the nation's agroecosystems from an ecological perspective through an inter- agency process. The specific objectives of the ARG parallel the overall EMAP objec- tives. When fully implemented the pro- gram will Estimate the status, trends, and changes in selected indicators of the condition of the nation's agroecological resources on a regional basis with known confidence. Estimate the geographic coverage and extent of the nation's agroecological resources with known confidence. Seek associations between selected Indicators of natural and anthropo- genic stresses and indicators of the condition of agroecological resources. Provide annual statistical summaries and periodic assessment of the nation's agroecological resources. An agroecosystem is a dynamic asso- ciation of crops, pasture, livestock, other plants and animals, atmosphere, soils, and water. The agroecosystem includes not only the field or pasture but also the asso- ciated border areas such as windbreaks, fence rows, drtchbanks, and farm ponds. The agroecosystem boundary depends on, and varies with, the process being consid- ered. Agroecosystems interact with larger landscapes, which include uncultivated land, drainage networks, human commu- nities, and wildlife. The landscape is the area that directly affects the ecology of the agroecosystems and is directly affected by agroecosystem processes. The land- scape boundary also depends on, and varies with, the process being considered. The sustainability of agroecosystems is of primary importance to the people of the United States and the world. Although there are several aspects of sustainability, the ARG is interested in the ecological sustainability of agroecosystems. An agroecosystem is ecologically sustainable ii it maintains or enhances its own long- term productivity and biodiversity, the biodiversity of surrounding ecosystems, and the quality of air, water, and soil. The EMAP-Agroecosystems monitoring effort is based upon assessment ques- tions related to three societal values. The three societal values for agroecosystems are the components of ecological sustainability: quality of air, water, and soil; productivity; and biodiversity. The ARG developed a multiyear pro- gram to establish the regional and na- tional implementation of a suite of indica- tors for monitoring the condition of agroecosystems. The first stage of the program (1990) encompassed the initial evaluation of (1) statistical designs; (2) existing monitoring programs (i. e., NASS, Soil Conservation Service, and Economic Research Service); (3) assessment ques- tions and associated indicators (for their availability, validity, variability, and cost); (4) data management and analysis tech- niques; and (5) methods of reporting on indicators. During 1990, a national moni- toring strategy was developed on the ba- sis of these evaluations. In the second stage of the program (1991) in-depth ex- aminations were conducted of several ar- eas critical to the planning and implemen- tation of the Pilot Field Programs: (1) sta- tistical design options; (2) measurements associated with specific indicators and as- sessment questions; (3) sampling proto- cols; (4) cooperation with NASS; (5) logis- tics; (6) quality assurance; and (7) infor- mation management. The 1992 Pilot in North Carolina, conducted in cooperation with USDA NASS, tested aspects of the monitoring program with a limited suite of indicators. Results of the 1992 Pilot will be used to develop (based upon availabil- ity of funds) additional pilots and regional demonstrations that eventually will lead to national implementation. Purpose and Objectives The 1992 Pilot was designed to evalu- ate aspects of the EMAP Agroecosystem monitoring program critical to the imple- mentation of a regional and national pro- gram. It was designed to address these program aspects over an area large enough to provide reliable answers to questions concerning the operation of the monitoring program but small enough to be physically and fiscally manageable. There were three major objectives of the 1992 Pilot: 1. Compare the relative efficiency, in terms of cost and precision, of two sam- pling frames. 2. Evaluate an initial suite of indicators to Assess the ability of each indica- tor to address the assessment questions of interest; Establish an initial range of values for each indicator across the di- verse physiographic regions of North Carolina; Assess spatial variability of indi- cator values within and among sample units; Identify the usefulness and sensi- tivity of each indicator in deter- mining ecological condition; and Determine cost-effectiveness for each indicator. 3. Develop and refine plans for Sampling Logistics Quality assurance Data analysis, summarization, and reporting Information management Ecological health indices and their interpretation The 1992 Pilot was also conducted to establish a cooperative, working relation- ship with NASS at both the state and national level. NASS has a well estab- lished nationwide network of enumerators experienced in conducting national sur- veys. Also, growers throughout the United States are familiar with NASS personnel and have confidence in NASS because of the NASS data confidentiality require- ments. North Carolina was selected for the 1992 Pilot because 1. The physiographic diversity of the state is representative of the ecoregions of the southeastern re- gion of the United States. 2. NASS is organized by state. Limit- ing the Pilot to one state simplified problem resolution. 3. Most of the ARG staff is located in Raleigh, NC, which facilitated lo- gistic activities. Design and Statistical Considerations The ARG considered two sampling plans in the 1992 Pilot, each of which used the NASS Area Frame segments as the basic sampling units. The two plans differ in the way the segments to be used for indicator sampling are selected. The Pilot study evaluated the results of a sampling strat- egy based on using the EMAP Hexagon Design to select the NASS segment to the Rotational Panel Plan that uses a sub- set of segments from the NASS June Enu- rnerative Survey (JES). Fifty-one segments distributed over 49 counties were used from the EMAP Hexagon Design and 65 segments distributed over 55 counties were used from the Rotational Panel Plan. Only fields planted with annually harvested ------- herbaceous crops were eligible for selec- tion as a sample unit. For each design, crops in each field in each segment were identified during the NASS JES. An aver- age of three fields were selected at ran- dom from each of the 65 segments for 195 sample units for the Rotational Panel Plan and from each of the 51 segments for 153 sample units for the Hexagon De- sign. Ten sample units from the Rota- tional Panel and 17 from the Hexagon Design were not sampled due to farmer .refusal, inaccessibility of the field, the field not being in the designated resource class, or enumerator error. Ponds and wells for sampling were iden- tified from lists developed by NASS from the North Carolina JES. Initially, 51 ponds and 81 wells were identified from the Ro- tational Panel Design only. Because of refusals and other factors identified previ- ously, 40 ponds and 61 wells were actu- ally sampled. Data were assembled from three sources: the JES, the EMAP Fall Survey questionnaire, and samples of soil and water collected by NASS enumerators. All questionnaire data were compiled by NASS and transmitted to the ARG. Soil samples were submitted to one commer- cial laboratory for analysis of physical and chemical parameters and to another com- mercial laboratory for nematode identifi- cation and enumeration. All water samples were analyzed by personnel and contrac- tors from EPA's Environmental Research Laboratory in Athens, GA. The primary statistical tool used to sum- marize indicator data from the 1992 Pilot is the cumulative distribution function (CDF). Ninety percent confidence bands were added to each CDF in order to indi- cate the precision of the estimated CDF. The population reported is typically the area of land in North Carolina, the Pied- mont region of North Carolina, or the Coastal Plain region of North Carolina cul- tivated with annually harvested herbaceous crops. Results Results are presented for the indicator categories land use, crop productivity, soil quality (physical and chemical), soil biotic diversity, water quality, and agricultural chemical use. In the full report, results for each indicator are presented in a question and answer format similar to what might be used in the future for annual statistical summaries. In a few cases, boundaries for acceptable (nominal), marginal, and unacceptable, (subnominal) conditions are presented. In most cases, however, con- dition boundaries are not proposed and will be developed for future reports. The following summarizes the results. Extent and Geographic Distribution of Annually Harvested Herbaceous Crops Annually harvested herbaceous crops are planted on about 1.68 million hectares and cover some 13% of the total land area in North Carolina. Crops included in the Pilot were barley, corn, cotton, hay, oats, peanuts, potatoes, rye, soybeans, sweet potatoes, sorghum, sunflowers, to- bacco, vegetables (all), and winter wheat. Information on extent and distribution of these crops was obtained by analyzing data from the complete NASS JES. Ques- tions answered include (1) how much land is cropped?; (2) how diverse are the state's croplands?; (3) do these cropped areas tend to be dominated by a single crop?; (4) how large are the crop fields?; and (5) how do different size fields contribute to the total area of annually harvested her- baceous cropland? For example, North Carolina fields tend to be small, with a median field size of just over two hectares regardless of the type of landscape. Addi- tionally, half of the total area of annually harvested herbaceous cropland occurs in fields smaller than 6.09 hectares. Crop Productivity Two indices of crop productivity are pre- sented: nitrogen use efficiency and stan- dardized (observed/expected) yield. Ques- tions answered are (1) how efficiently is nitrogen being used to produce annually harvested herbaceous crop? and (2) is crop productivity meeting expectations based on soil and climate? Nitrogen use efficiency is the ratio of the amount of nitrogen applied to a field to the harvested yield from that field. Thus, the smaller the number the greater the nitrogen use efficiency. Information for cal- culating this index was obtained from the EMAP Fall Survey questionnaire. Fifty per- cent of the land area in North Carolina cropped to corn, wheat, soybean, and cot- ton had nitrogen use efficiencies of 0.029, 0.035, 0.011, and 0.120 or less, respec- tively. For all seed crops combined, 50% of the land area planted to these crops in North Carolina had nitrogen use efficien- cies of 0.022 or less. Standardized yield was calculated in re- lation to an 11 -year reference period in an initial attempt to answer the question: how can data from different crops be brought together in a single productivity index? The eventual goal is to answer the ques- tion: is crop productivity meeting expecta- tions based on soil and climate? If ob- served and expected yields are the same, standardized yield has a value of 1.0; if observed yields are greater than expected, the index has a value greater than 1.0; and if observed yields are less than ex- pected, the index has a value less than 1.0. The median value for all the observed/ expected indices presented is greater than 1.0. This index presented for a single year has little meaning; however, over the long term this type of index should reflect changes or trends in overall crop produc- tivity. Soil Quality - Physical and Chemical Physical and chemical properties of soils largely determine and reflect the produc- tive potential of land. For the 1992 Pilot, we analyzed composite samples from the AP horizon for particle size, organic mat- ter, cation exchange capacity, selected micro- and macronutrients, and some con- taminants related to sludge application. Questions posed include (1) do soils have acceptable amounts of clay to sustain crop production?; (2) do the soils have accept- able levels of organic matter in order to provide aeration to the roots and retain nutrients?; (3) do soils have pH levels that facilitate the availability of essential plant nutrients?; (4) do the soils have cation exchange capacities that enable nutrient storage and supply?; (5) do the soils have adequate plant available phosphorus to sustain plant growth?; and (6) do the soils have lead or cadmium levels that pose health risks to the ecosystem? As an example, ranges of 18-35% clay content and organic matter content of greater than 1 % are proposed as accept- able levels to promote growth of crop plants. Based upon these criteria, the pro- portion of land cropped with annually har- vested herbaceous crops that have soils with acceptable levels of clay and organic matter for growth of crop plants is 0.36 in the Piedmont, 0.10 in the Coastal Plain, and 0.30 for the state as a whole. Soil Biotic Diversity Biotic communities in soil are respon- sible for the decomposition of organic mat- ter, are involved in many aspects of nutri- ent cycling, provide mechanisms for the development of pore spaces within soil, and interact with plant roots. The status of ------- the soil biota is vital to the overall charac- terization of soil condition or health. Nematodes may serve as a good indi- cator of soil condition because they are diverse in their feeding habits and occur as central members of the soil food web. A highly stable or mature community of nematodes would indicate minimal distur- bance or contamination of the soil biota. Questions answered in the Pilot included (1) what is the degree of stability or matu- rity in nematode communities in soil? and (2) what is the degree of diversity of nema- todo communities in soil? For land cultivated in annually harvested herbaceous crops in the Piedmont and Coastal Plain regions of North Carolina, only a small proportion of communities of soil nematodes had a relatively high de- gree of stability or maturity. The propor- tion of land area cultivated with annually harvested herbaceous crops having val- ues for the maturity index for free-living nematodes of less than 3.2 on a 1-5 scale (where 5 is the most mature or stable community) was estimated to be 0.95. A higher proportion of larger values (>3.0) was found for soils in the Piedmont than in the Coastal Plain region for both free- living and plant-parasitic nematodes. Trophic diversity values had a greater range in the Piedmont than in the Coastal Plain with higher index values occurring in the Piedmont. Water Quality Water is essential to any agroecosystem, and it carries materials from the agroecosystem into the larger landscape. Ponds and wells were sampled during the fall sample of the Pilot, and water samples were analyzed for two types of contami- nants: nitrates and pesticides. Questions addressed include (1) what is the distribu- tion of nitrate concentrations in wells on farms in North Carolina?; (2) what is the distribution of nitrate concentrations in farm ponds in North Carolina?; and (3) how extensive is pesticide contamination of farm ponds and wells in North Carolina? For wells, the EPA maximum contami- nant level for water is 10 ppm nitrate-N. From the Pilot data, an estimated 3.5% of wells had greater than 10 ppm nitrate-N, and the median concentration was ap- proximately 1 ppm. The maximum con- centration detected was 19 ppm nitrate-N. In farm ponds, concentrations of nitrate-N were generally less than those found in wells with a median concentration of 0.2 ppm, A spectrum of 12 insecticides/ nematicides and herbicides was not de- tected above the one part per billion thresh- old in any sample fronvwells or ponds. Agrichemical Use Fertilizers and pesticides are integral components in the production of crops in agroecosystems. Applications of materi- als in both of these agrichemical catego- ries can result in both positive and nega- tive effects on the biological components of agricultural systems. A preliminary ques- tion addressed in the Pilot was how much stress is put on the ecosystems of North Carolina by applying chemical fertilizers and pesticides? Extent of use of agrichemicals may be one indication of potential stress placed on agricultural systems. As an example, extent of use of four materials was con- sidered: the herbicide atrazine; the bio- logical control agent Bt or Bacillus thuringiensis (used against insect pests); the insecticide/nematicide carbofuran; and the commercial fertilizer nitrogen. Atrazine, Bt, carbofuran, and fertilizer nitrogen were applied at least once to 17.8, 0.8, 2.1, and 75.5% of the land area of annually har- vested herbaceous crops in North Caro- lina. Atrazine was applied an average of 1.06 times and fertilizer nitrogen an aver- age of 1.72 times per year. Evaluation of Designs, Indicators, and Activities Design comparisons were performed primarily for fall questionnaire and soil sample data. Only statewide estimates were used and the comparison was done both accounting for and ignoring stratifica- tion by intensity of agricultural use, which was provided by NASS. The efficiency of one design relative to another was de- fined as the ratio of the variances for the statistic of interest, adjusted for different sample sizes when necessary. A relative efficiency greater than one indicates that the Hexagon Design is more efficient, whereas a relative efficiency less than one indicates that the Rotational Panel Design is more efficient. For eight measures of soil quality (physical and chemical) and two measures of crop productivity, ac- counting for stratification, the Rotational Panel Design was more efficient in eight cases and the Hexagon design was more efficient in two cases. When relative effi- ciency was calculated with cost included as a factor, the Rotational Panel Design was always the more efficient design. Successes and challenges in indicator development and evaluation were specific to the indicator considered. In general, indicators performed well; however, the suite of indicators is not yet sufficiently well developed to fully assess the ecologi- cal condition of agricultural systems. For assessing crop productivity, one challenge is how to successfully bring together dif- ferent crops into a single, interpretable productivity index. For assessing soil qual- ity, the challenge is to develop a single, interpretable index that incorporates the key physical, chemical, and biological fac- tors of soil health. For assessing the ex- tent and geographic distribution of annu- ally harvested herbaceous crops, one chal- lenge is to provide a clear interpretation of crop diversity or land use diversity indices that can be calculated. For agrichemical use, a challenge is how to integrate EMAP- Agroecosystems data with information al- ready collected by other federal agencies. Another challenge for all indicators is to quantify the frequency and magnitude of measurement errors. Activities in all areas of the Pilot were generally successful. The interactions with NASS personnel were very successful with NASS personnel involved in four areas of the Pilot: (1) collecting data during their regular JES; (2) drawing the sample of fields to be visited in the fall; (3) designing and conducting the fall questionnaire; and simultaneously (4) collecting fall soil and water samples. The Pilot was generally a logistical success. Questionnaire perfor- mance and survey administration, soil sam- pling, water sampling, shipping and sample tracking, laboratory relations, and report- ing back to respondents generally occurred in a satisfactory manner. The quality as- surance (QA) aspects of the Pilot pro- ceeded in two components as planned. NASS has a well-established QA program and EPA personnel performed successful field audits during data collection and labo- ratory audits during sample analysis. With regard to information management, the primary goalto develop a cooperative, working relationship with NASSwas achieved. Extensive discussions within the ARG and with personnel in partner agen- cies have been held to review Pilot activi- ties, and lessons learned will contribute to the success of future efforts. Conclusions The 1992 Pilot in North Carolina pro- vided an initial test of the concepts relat- ing to design, sampling, indicator devel- opment, data analysis, quality assurance, logistics, and information management. A preliminary comparison of the efficiency of two sampling frames or designs was made. An initial suite of indicators for the extent and distribution of cropland, crop productivity, soil quality, water quality, and agrichemical use was evaluated with re- ------- spect to the ability of indicators to address assessment questions; the spatial vari- ability of indicator values within and among sample units; the usefulness of each indi- cator in determining condition; and the cost-effectiveness of each indicator. Plans for sampling; logistics; quality assurance; data analysis, summarization, and report- ing; and information management were made, carried out, and evaluated. The information obtained from the Pilot will allow the ARG to continue to evaluate and develop the program components es- sential for the eventual implementation of regional and national monitoring programs to assess the condition of the Nation's agricultural systems. - This research was funded primarily by the U.S. Environmental Protection Agency (EPA) through its Office of Research and Development under Interaqency Agree- ment Nos. DW12934170 with the U.S. De- partment of Agriculture, Agricultural Re- search Service, and DW1293747 with the USDA National Agricultural Statistics Ser- vice. It was conducted by our research partners under the management of the En- vironmental Monitoring Systems Laboratory, Las Vegas, in support of the Environmental Monitoring and Assessment Program. &U.S. GOVERNMENT PRINTING OFFICE: 1994 - 55O-M7/80270 ------- ------- ------- C. Lea CampbalUs with the USDA Agricultural Research Service, Raleigh, NC 27606; Jeff M. Bay, Karen £ Nauman, Kurex Sidik, David W. Turner, Anne S. Hellkamp, George R. Hess, MichaselJ. Munster, Deborah A. Neher, Steven L. Peck, and Mark B. Tooley are with North Carolina State University, Raleigh, NC 27695; GailL Olsen is with EG&G Idaho, Inc., Idaho Falls, ID 83415; and the EPA author, Brian A. Schumacher, is with the Environmental Monitoring Systems Laboratory, Las Vegas, NV 89193-3478. Susan E. Franson is the EPA Project Officer (see below). The complete report, entitled "Environmental Monitoring and Assessment Program: Agroecosystem Piht Field Program Report - 1992," (Order No. PB94-179 819 Cost: $27.00, subject to change) will be available only from: National Technical Information Service 528S Port Royal Road Springfield, VA 22161 Telephone: 703-487-4650 The EPA Project Off her can be contacted at: Environmental Monitoring Systems Laboratory U.S. Environmental Protection Agency Las Vegas, NV 89193-3478 United States Environmental Protection Agency Center for Environmental Research Information Cincinnati, OH 45268 Official Business Penalty for Private Use $300 BULK RATE POSTAGE & FEES PAID EPA PERMIT NO. G-35 EPA/620/SR-94/014 ------- |