Sussex / Kent Counties Agricultural Tracking Census, Sussex Conservation District, Delaware

Karin Grosz

The increase in number of agricultural operations combined with a sharp rise in development has created an 89% impairment of the quality of Delaware’s waterways. Sussex is the largest poultry-producing county in the US. For conservation and nutrient management planners to know where to focus their attention via agricultural and financial assistance programs, an agricultural census was needed. A census project was designed and executed road-by-road using ArcView software as the central platform. Ultimately a unique, flexible and accurate database was created that can track, produce maps, be updated and shared with interested parties while protecting individual landowner privacy.

Conservation work in Sussex and Kent Counties, the two largest of the three counties comprising the state of Delaware, has been ongoing since the early 1940s enabled by agencies such as the Soil Conservation Service (SCS), now Natural Resources Conservation Service (NRCS), Farm Service Agency (FSA) once Agriculture Stabilization and Conservation Service (ASCS), and the Sussex and Kent Conservation Districts (KCD and SCD)(see Note 1). Delaware, with a land area of 1,954 square miles, is the second smallest state of the United States. Bordered by Pennsylvania, New Jersey, Maryland and Virginia, Delaware rests aside Maryland’s eastern shore which together with a small area of Virginia make up the Delmarva Peninsula, geologically a part of the more recently formed coastal plain. Due to a favorable climate and good economic conditions, agricultural enterprises in the southern part of the state have shown sixty years of consistent growth. As a result of these factors Sussex County is the largest poultry-producing county in the United States and the largest soybean- producing county east of the Appalachian mountains(see Note 2). Sussex County has held that honor for more than five years. It is also the birthplace of the modern broiler (poultry) industry.

The growth in the size and number of agricultural operations over the past decades, combined with increasing development in the form of urban sprawl, largely unplanned, in areas closest to wetlands, inland bays and rivers, has created an overabundance of nutrients leaching into Delaware’s waterways. The nutrients are primarily in the form of non-point source phosphorus and nitrogen from historic over-application of organic fertilizer to cropland, septic system leachate and atmospheric deposition. However, point sources, such as effluent from industrial and municipal wastewater, have contributed as well(see Note 3).

The practice of using poultry manure as fertilizer has been a tradition of generations of Delmarva’s farmers. Poultry manure is a relatively inexpensive and readily available byproduct of poultry production and is owned by the farmers. Poultry manure contains phosphorus three to four times greater in ratio to nitrogen at the crop removal rate, which is calculated to be three tons per acre for corn(see Note 4), or 111 pounds of nitrogen. One third of all soil samples from Sussex County tested by the University of Delaware soils laboratory from 1992 to1997 showed the residual levels of phosphorus to be three times higher than most plants need for adequate nutrition. Phosphorus, tightly bound to soil particles, has been found to migrate by sheet or rill erosion into surface water, once soil-binding capacity has been reached. A phosphorus site index has been developed for Delaware’s nutrient management planners to use when soil phosphorus test values reach 150 FIV or above and, in the future, phosphorus will be the limiting factor in crop fertilization.

After intensive surveying, the Delaware Department of Natural Resources and Environmental Control in 2000 reported that a significant percentage(see Note 5) of Delaware’s waterways, encompassing 2,509 miles of navigable rivers and streams and 2,954 acres of lakes and ponds, was impaired(see Note 6). Reasons cited included nutrient enrichment, high levels of bacteria, low dissolved oxygen, toxic substances, insufficient habitat quality, lack of riparian vegetation, and habitat degradation. The State of Delaware’s Watershed Assessment Report fulfilled requirements of reporting required by Section 305 (b) of the 1972 Federal Clean Water Act and the State’s subsequently published Section 303 (d) list fulfilled the Act’s requirement of states to develop a list of water bodies that needed additional pollution reduction beyond that provided by the application of existing controls(see Note 7). Additional pollution reduction would result by developing and implementing total maximum daily loads (TMDL) for each segment. A total maximum daily load sets a limit on the amount of a pollutant that can be discharged into a water body while still supporting the designated uses of the water body.

One of the ways in which agricultural operations are addressing the TMDL issue is by the construction of poultry carcass composters and poultry manure sheds for both the mortality and the manure from poultry operations. Composters insure swift and complete disposal of carcasses on-farm, creating a product that can be mixed with and spread as fertilizer, while manure sheds keep poultry manure dry during the winter until such time as it is convenient and appropriate to spread on fields. The spreading of manure on frozen or snow-covered fields is discouraged. Both structures, known to cost-share programs as best management practices or BMPs, help reduce nutrient-laden runoff from occurring on the farm and preserve the commodity value.

Delaware’s first poultry carcass composter was built in 1988 as a demonstration project. As word got around the farming community that poultry composters and manure sheds worked well, more farmers wanted them, and their construction was supported with funds from such programs as PL-566, Environmental Quality Incentives Program (EQIP), ASCS/FSA and Conservation District cost-share.

As time went on and more of these structures were built, it became necessary for conservation and nutrient management planners to start tracking their whereabouts in order to know which areas, by sub-watershed, could benefit the most from continued attention via agricultural financial assistance programs. An agricultural census was needed.

Historically, various attempts had been made in Sussex and Kent Counties to field census agricultural operations, but the collected data was inconclusive and not easily adaptable to existing software. The conservation district sent one of their planners to learn basic ArcView in 1998 and later that same year a singular census project was designed using ArcView software as it’s central structural platform. The intention of the project was to create an accurate field census of every agricultural operation in Sussex County. Having ArcView as the software and a powerful computer enabled the GIS specialist to organize the project from beginning to end without leaving the desk. First, using Delaware’s 1997 digital orthophotos, a preliminary visual census of confined animal feeding operations (CAFO), animal feeding operations (AFO) and BMPs was made subwatershed by subwatershed and created as a shapefile in an ArcView project. Useful was a piece of script that had been developed whereby a customized interface allowed the planner to use a tool to point to an area on a conventional state map and click and the appropriate orthophoto would load at the desired scale which for this project was 1:20,000. Reading from orthophotos takes skill and it was clear that in the project’s case the results, still just a visual template at this stage, would have to be field-tested, road-by-road, in order to be considered of merit statistically from a technical point of view. It is unknown, for example, if the poultry houses one can see on the orthophoto are, in fact, being operated until one drives by.

The next step in setting up the field work was to assemble county road maps, make larger copies of them in sections, delineate the subwatersheds on them with colored markers, and send the planners out, two by two, (one to drive, one to look), to notate operations on the maps. No properties were trespassed upon; sheds and composters that were visible from roadside were annotated on the field maps. Each day the planners would return with completed maps. The GIS specialist would then systematically enter the new data in a new shape file for that subwatershed in the original project, once again using orthophotos and county map roads as a visual guide. The project grew daily as data was entered for each subwatershed and layers such as hydrological, aerial and land-based information were added. A historical layer containing previously constructed sheds and composters was compiled.

From the set of collected data on animal operations, sheds, composters and ag waste systems, a classification system for the legend was designed. The categories for the legend included poultry, beef, dairy, swine, equine, other (buffalo, goat, llama, etc), out of production operations, manure sheds, composters and ag waste systems. Themes were then defined from the single data source based on the categories of the legend. For example, the theme for poultry would be defined as data = "*P*", equine as data = "*E*" and so forth. Each theme was assigned its own symbol from the ArcView symbol listing and then sized and colored differently from the others. Using unique symbols for each theme helped make it possible for anybody to easily and quickly see the spatial distribution of the practices on the maps.

The entire project in Sussex County took a period of several weeks of full days driving time (4,643 lane miles according to Delaware Department of Transportation) with one set of two planners working each day. Successful in Sussex County, the project was asked to do the same census in Kent County in year 2000. The Kent County work was accomplished in just over two weeks time with one set of two planners each driving daily for a total of 2,843 lane miles in all. Kent County has a larger Amish and Mennonite farm concentration than Sussex and fewer poultry operations.

In summary, a unique and scientifically accurate tool was created with ArcView that not only has the capability of keeping track of the District’s nutrient management planning and best management practices over time as the work progresses, but also can be divided into smaller information parcels and sent to interested parties electronically, all while protecting individual landowner privacy. The census project now has capacity to expand and develop to meet future needs and to incorporate new technology as it becomes useful.

Note 2: Delaware Agricultural Statistics Service. 2001. Delaware Agricultural Statistics Summary for 2001, Delaware Department of Agriculture and USDA, National Agricultural Statistics Service.

Note 3: Delaware Department of Natural Resources and Environmental Control. 2001. Inland Bays/Atlantic Ocean Basin Assessment Report. Delaware Department of Natural Resources and Environmental Control, Dover, Delaware.

Note 4: The University of Delaware assigns 37 pounds nitrogen, three pounds ammonium-N, 20 pounds phosphorus and 26 pounds potassium per ton of typical broiler chicken litter taken directly from the poultry house be used in factoring poultry manure applications for nutrient management plans. University of Delaware Cooperative Extension, Delaware Handbook for Nutrient Management Certification, Delaware Nutrient Management Program, Dover, Delaware.

Note 5: 96% of rivers and streams do not fully support swimming use and 71% do not fully support fish and wildlife use; 69% of fresh water ponds and lakes do not fully support swimming use and 27% do not fully support fish and wildlife use.

Note 6: The report includes a description of the water quality of all navigable waters in the state, an analysis of the extent to which the waters provide protection and propagation of a balanced population of shellfish, fish, and wildlife and allow recreational activities in and on the water, and other environmental, social and economic factors. The report is due April 1^st of every even-numbered year.

Note 7: These waters are referred to as "Water Quality Limited" and must be identified by the state or EPA. Water Quality Limited waters require development of a total maximum daily load (TMDL). These waters are identified on the 303(d)list.

The author is grateful to Tom Boyce, Dale Churchey, Kip Foskey and Kevin Ryan for skillful execution of field operations; to Eric Helm Buehl, District Coordinator ex officio for understanding the scope of the project, to John Inkster for his computer knowledge and skillful script writing; and to DNREC Division of Soil and Water Section 319 Program for funding and support.

Kenneth W. Staver and Russell B. Brinsfield, "Agriculture and Water Quality on the Maryland Eastern Shore: Where Do We Go from Here?," BioScience 51, no. 10 (October 2001): 859-868.

Joann M. Burkholder and Howard B. Glasgow, "History of Toxic Pfiesteria in North Carolina Estuaries from 1991 to the Present," Ibid. : 827-841.