*>EPA United States Environmental Protection Agency Source Water Protection Practices Bulletin Managing Agricultural Fertilizer Application to Prevent Contamination of Drinking Water If improperly managed, elements of fertilizer can move into surface water through field runoff or leach into ground water. The two main components of fertilizer that are of greatest concern to source water quality (ground water and surface water used as public drinking water supplies) are nitrogen (N) and phosphorus (P). This fact sheet focuses on the management of agricultural fertilizer applications; see the fact sheets on managing agricultural pesticide use, animal waste, and storm water runoff for other prevention measures that relate to agriculture. Inside this issue: Why is it Important to 2 Manage Fertilizer Use? Available Prevention 3 Measures Additional Information 6 1 - Fertilizer tractor. Fertiliser Use in Agriculture Fertilizer application is required to replace crop land nutrients that have been consumed by previous plant growth. It is essential for economic yields. However, excess fertilizer use and poor application methods can cause fertilizer movement into ground and surface waters. While fertilizer efficiency has increased, Colorado State University estimated that about 25 percent of all preplant nitrogen applied to corn is lost through leaching (entering ground water as nitrate) or denitrification (entering the atmosphere as nitrogen gas). Fertilizer and Fertilizer Use Facts: • The Nitrogen and Phosphorus in fertilizer are the greatest concern to source water quality. • 25% of all preplant N applied to corn is lost through leaching or dentrification. • 60-90% of P moves with the soil. • Consumption of nitrates can cause "blue baby syndrome". • Nitrate has a drinking water MCL of 10mg/l. • Nutrient management abates nutrient movement by minimizing the quantity of nutrients available for loss. • Fertilizer applied in the fall causes ground water degradation. Partial application in the spring can improve N uptake. • Ammonium N fertilizers are not subject to immediate leaching, but convert to nitrate. ------- Page 2 Source Water Protection Practices Bulletin Why is it Important to Manage Fertiliser Use Near Sources of Drinking Water? Improper or excessive use of fertilizer can lead to nitrate pollution of ground or surface water. Nitrogen fertilizer, whether organic or inorganic, is bio- logically transformed to nitrate that is highly soluble in water. In this soluble form, nitrate can readily be absorbed and used by plants. On the other hand, soluble nitrate is highly mobile and can move with percolating water out of the soil, thus making it unavail- able for plant uptakes. Crop produc- ers, therefore, need to match nitrogen applications to crop uptake to mini- mize nitrate leaching and maximize efficiency. Use of nitrogen-containing fertilizers can contribute to nitrates in drinking water. Consumption of nitrates can cause methemoglobinemia (blue baby syndrome) in infants, which reduces the ability of the blood to carry oxygen. If left untreated, methemoglobinemia can be fatal for affected infants. Due to this health risk, EPA set a drinking water maximum contaminant level (MCL) of 10 milligrams per liter (mg/l) or parts per million (ppm) for nitrate measured as nitrogen. Another major component of fertilizer is phosphorus. Under certain condi- tions phosphorus can be readily trans- ported with the soil. In fact, 60 to 90 percent of phosphorus moves with the soil. Phosphorus is the major source of water quality impairments in lakes nationwide. Even though regulations that affect the taste and odor of water are not Federally enforceable under the Safe Drinking Water Act, munici- palities often must treat their drinking water supplies for these aesthetic rea- sons. The use of organic nutrient sources, such as manure, can supply all or part of the nitrogen, phosphorus, and po- tassium needs for crop production. However, organic fertilizers can also cause excessive nutrient loads if improperly applied. Blue Baby Syndrome Effects Superior vena Cava Pulmonary r'ulmonary 2 - Healthy hearts. Right Atrium '""Aortic Pulmonary valve Right Ventricle Tricuspid •" Valve nfertor Vena Cava Small (hypoplastic) aorta Patent (open) ductus arteriosus Atrial septal defect opening betwee-n the atrial SF- Small (hypoplastic] left veniriculum 4 - Hypoplastic left heart syndrome. 3 - dextro-Transposition of the great arteries, dTGA. Oxygenated blood shown in dark pink (above left) 5 - Tricuspid atresia 6 - Tetralogy of Fallot, vena cava Pulmonary 1 artery I Left\ satrium Ventricle Superior Pulmonary vein Atresic tricuspid valve Rudimentary right ventricle Inferior vena cava Overriding aorta Pulmonic stenosis ventricular septal defect Right ventricular hypertrophy ------- Source Water Protection Practices Bulletin Page 3 Available Prevention Measures to Address Agricultural Applications of Fertiliser This section discusses some of the most often used prevention meas- ures, but is not an exhaustive list of all known measures. For information on additional prevention measures, see the documents referenced in the last section of this fact sheet. Please keep in mind that individual preven- tion measures may or may not be adequate to prevent contamination of source waters. Most likely, individual measures should be combined in an overall prevention approach that considers the nature of the po- Comprehensive Nutrient Management Plans include soil sampling, crediting other sources of nutrients and limiting fertilizer use. Application Kates and Fertiliser Types tential source of contamination, the purpose, cost, operational, and main- tenance requirements of the meas- ures, the vulnerability of the source water, the public's acceptance of the measures, and the community's de- sired degree of risk reduction. The goal of these prevention meas- ures is to minimize nutrient losses from agricultural lands occurring by edge-of-field runoff and by leaching from the root zone. Effective nutrient management abates nutrient move- ment by minimizing the quantity of 7, 8, 9, 10 - Seasons, One component of a comprehensive nutrient management plan is to de- termine proper fertilizer application rates. The goal is to limit fertilizer to an amount necessary to achieve a realistic yield goal for the crop. Soil sampling and crediting other sources are also parts of the concept. Yearly soil sampling is necessary for determining plant nutrient needs and to make accurate fertilizer recom- mendations. Many factors must be considered when determining sam- pling methods and frequency. Calculating the optimal rate of appli- cation also includes crediting other sources that contribute nitrogen and phosphorous to the soil. Previous legume crops, irrigation water, manure, and organic matter all con- tribute nitrogen to the soil, while or- ganic matter and manure contribute phosphorus. Along with soil samples and fertilizer credits from other sources, nitrogen fertilizer recommendations are based on yield goals established by the crop producers. Yield expectations are established for each crop and field based on soil properties, avail- able moisture, yield history, and management level. Applying the appropriate form of ni- trogen fertilizer can reduce leaching. Nitrate forms of nitrogen fertilizer are readily available to crops, but are subject to leaching losses. Nitrate fertilizer use should be limited when nutrients available for loss. This is achieved by developing a compre- hensive nutrient management plan and using only the types and amounts of nutrients necessary to produce the crop, applying nutrients at the proper times and with proper methods, implementing additional farming practices to reduce nutrient losses, and following proper proce- dures for fertilizer storage and han- dling. Fertiliser Application Timing Nitrogen fertilizer applications should be timed to coincide as closely as possible to the period of maximum crop uptake. Fertilizer applied in the fall has been shown to cause ground water degrada- tion. Partial application of fertilizer in the spring, followed by small additional applications as needed, can improve nitrogen uptake and reduce leaching. Reasons to alter nitrogen amounts include abnormal weather or crop quality. the leaching potential is moderate to high. In these situations, ammonium nitrogen fertilizers should be used because they are not subject to imme- diate leaching. However, ammonium nitrogen transforms rapidly into nitrate when soils are warm and moist. More slowly available nitrogen fertilizers should be used in these conditions. Nitrification inhibitors can also delay the conversion of ammonium to ni- trate under certain conditions. Phosphorus fertilizer is less subject to leaching, but loss through surface runoff is more common. To minimize losses of phosphorus fertilizer, appli- cations should only be made when needed (determined through soii testings) and at recommended rates. ------- Page 4 Source Water Protection Practices Bulletin Fertiliser Application Methods Fertilizer application equipment, should be inspected at least once annually. Application equipment must also be properly calibrated to insure that the recommended amount of fertilizer is spread. Correct fertilizer placement in the root zone can greatly enhance plant nutrient uptake and minimize losses. Subsurface applied or incor- porated fertilizer should be used instead of a surface broadcast fertil- izer. The most efficient application method for many crops, especially in erosive soils, is to place dry fertil- izer into the ground in bands. Band or drilled row fertilizers are applied closer to the seed and can be recovered by the crop more effi- ciently. All surface-applied fertilizers should be mechanically incorporated into the soil to reduce losses through surface runoff and volatilization. Fer- tilizer should never be applied to fro- zen ground, and also should be lim- ited on slopes and areas with high runoff or overland flow. Irrigation water should be managed to maximize efficiency and minimize runoff or leaching. Irrigated crop pro- duction has the greatest potential for source water contamination because of the large amount of water applied. Both nitrogen and phosphorus can leach into ground water or run off into surface water when excess water is applied to fields. Irrigation systems, such as sprinklers, low- energy precision applications, surges, and drips, allow producers to apply water uniformly and with great efficiency. Efficiency can also be im- proved by using delivery systems such as lined ditches and gated pipe, as well as reuse systems such as field drainage recovery ponds that efficiently capture sediment and nu- trients. Gravity-controlled irrigation or furrow runs should be shortened to prevent over-watering at the top of the furrow before the lower end is adequately watered. 11 - Crop bands. A complete system is needed to reduce fertilizer loss. Components of this system often include farming practices that are not strictly related to fertilizer, such as conservation tillage and buffers. Correct fertilizer placement in the root zone can greatly enhance plant nutrient uptake and minimize losses. Subsurface applied or incorporated fertilizer should be used instead of a surface broadcast fertilizer. Conservation Tillage Conservation tillage is another field management method used to reduce runoff. In conservation tillage, crops are grown with minimal cultivation of the soil. When the amount of tillage is reduced, the plant residues are not completely incorpo- rated and most or all remain on top of the soil. This practice is critical to reducing phosphorus losses because the residue provides cover and thereby reduces nutrient runoff and erosion by water. 12 - Conservation tillage. ------- Source Water Protection Practices Bulletin Page 5 Irrigated crop production has the greatest potential for source water contamination because of the large amount of water applied, Creating buffer strips or filter strips can impede run- off and help filter nitrogen and phosphorus from runoff. Buffer strips and filter strips are created by planting dense vegetation near surface water bod- ies. The root systems of these plants hold soil in place, thereby decreasing the velocity of runoff and preventing erosion. The vegetation and soils strain and filter sediments and chemicals. For more infor- mation on buffer strips and filter strips see the fact sheet on storm water runoff. 14 - Buffer strip. 13 Crop rotation. Crop rotation can often yield crop improvement and economic benefits by minimizing fertilizer and pesticide needs. Planting legumes as part of a crop rotation plan provides nitrogen for subsequent crops. Deep-rooted crops can be used to scavenge nitrogen left in the soil by shallow-rooted crops. Cover crops stop wind and water erosion, and can use residual nitrogen in the soil. Field Leveling A high-tech way to level or grade a field is to use laser-controlled land leveling equipment. Field leveling helps to con- trol water advance and improve uni- formity of soil saturation in gravity-flow irrigation systems. This improves irriga- tion efficiency and reduces the potential for nutrient pollution through runoff. 15 - Laser-controlled land leveling. Fertiliser Storage and Handling Follow label directions for storing and mixing fertilizer and for disposing empty containers. Lock or secure storage container valves when the container is not in use. Protect permanent fertilizer storage and mixing sites from spills, leaks, or storm water infiltration. Storage buildings should have impermeable floors and be securely locked. Impermeable secondary containment dikes can also be used to contain liquid spills or leaks. Do not store fertilizer in underground containers or pits. To prevent accidental contamination of water supplies, mix, handle, and store fertilizer away from wellheads and surface water bodies. Installing anti-backflow devices on equipment can also prevent spillage. Ideally, mix and load fertilizers at the application spot. Immediately recover and reuse or properly dispose of spills. Granular absorbent material can be used at the mix- ing site to clean up small liquid spills Control box Laser beam Laser Transmitter ------- Page 6 Source Water Protection Practices Bulletin Additional Information These references have information on agricultural fertilizer use and best management practices. All of the following documents are available for free on the internet. You should also contact the U.S. Department of Agriculture (USDA), Natural Resources Conservation Service (NRCS), Conservation District, and Agricultural Extension Service representa- tives in your area for more information on nutrient management and cost-share programs, such as the Environmental Quality Incentives Program (EQIP), the Conservation Reserve Program (CRP), and the Conservation Reserve Enhance- ment Program (CREP), to assist in financing source water protection measures. Contact local government authorities in your area to see if there are ordinances in place to manage fertilizer use. Numer- ous examples of local source water protection-related ordinances for various potential contaminant sources can be found at: http://www. epa .gov/r5water/ord com/ h tt p: //www .epa.gov/owow/nps/ordinance/ http://www.epa.gov/owow/nps/ordinance/links.htm The following documents provide more detailed information on prevention measures for fertilizer use on the farm Colorado State University Cooperative Extension. Best Management Practices for Nitrogen Fertilization (XCM-172). (1994, August). Retrieved February 9, 2001 from the World Wide Web: http://www.ext.colostate.edU/PUBS/CROPS/pubcrop.html#soil Colorado State University Cooperative Extension. Best Management Practices for Pesticide and Fertilizer Storage and Handling (XCM-178). (1994, August). Retrieved February 9, 2001 from the World Wde Web: http://www.ext.colostate.edU/PUBS/CROPS/pubcrop.html#soil Colorado State University Cooperative Extension. Best Management Practices for Phosphorus Fertilization (XCM-175). (1994, August). Retrieved February 9, 2001 from the World Wde Web: http://www.ext.colostate.edU/PUBS/CROPS/pubcrop.html#soil Farm*A*Syst - University of Wisconsin. Retrieved May 22, 2001 from the World Wide Web: http://www.uwex.edu/farmasyst/ Kansas State University Cooperative Extension Service. Best Management Practices for Nitrogen. (1996, March). Re- trieved February 9, 2001 from the World Wide Web: http://www.oznet.ksu.edU/library/ageng2/#WaterQuality Kansas State University Cooperative Extension Service. Best Management Practices for Phosphorus. (1998, February). Retrieved February 9, 2001 from the World Wde Web: http://www.oznet.ksu.edU/library/ageng2/#WaterQuality North Carolina State University. Sustainable Practices for Vegetable Production in the South -Conservation Tillage. (1997, July 9). Retrieved March 14, 2001 from the World Wide Web: http://www.cals.ncsu.edu/sustainable/peet/tillage/c03tilla.html Purdue University Extension Service. Fertilizer Storage and Handling on the Farm. (1999). Retrieved February 12, 2001 from the World Wde Web: http://pasture.ecn.purdue.edu/~epados/farmstead/fert/src/title.htm Texas Agricultural Extension Service. Reducing the Risk of Ground Water Contamination by Improving Fertilizer Storage and Handling (B-6026). (n.d.). Retrieved February 9, 2001 from the World Wide Web: http://agpublications.tamu.edu/catalog/index.html University of Maryland - Cooperative Extension. Agricultural Nutrient Management. Retrieved May 22, 2001 from the World Wde Web: http://www.agnr.umd.edu/users/agron/nutrient/ University of Saskatchewan, Department of Agriculture. Fertilizer: The Basics, (n.d.). Retrieved February 16, 2001 from the World Wide Web: http://www.ag.usask.ca/cofa/departments/hort/hortinfo/misc/fertiliz.html U.S. Department of Agriculture. Irrigation Systems and Land Treatment Practices. (2001, February 6). Retrieved March 14, 2001 from the World Wde Web: http://151.121,66.126/Briefing/wateruse/Questions/glossary.htm U.S. Department of Agriculture, Natural Resources Conservation Service. Comprehensive Nutrient Management Plan- ning - Technical Guidance. (2000, December). Retrieved April 30, 2001 from the World Wde Web: http://www.nhq.nrcs.usda.gov/PROGRAMS/ahcwpd/ahCNMP.html ------- Source Water Protection Practices Bulletin Page 7 U.S. Department of Agriculture, Natural Resources Conservation Service. Conservation Practices Training Guide. (1999, August). Retrieved April 30, 2001 from the World Wide Web: http://www.ftw.nrcs.usda.gov/tech_ref.html Virginia Cooperative Extension. Fertilizer Storage, Handling, and Management (442-906). (1996, June). Retrieved Feb- ruary 9, 2001 from the World Wde Web: http://www.ext.vt.edu/pubs/farmasyst/442-906/442-906.html 1 - Flickr Creative Commons, attribute only search, liquid fertilizer application uploaded by "eutrophication&hypoxia" on March 31, 2010. http://www.flickr.eom/photos/48722974@N07/4478367887/ 2 - Wikipedia. Diagram of the Human Heart: http://commons.wikimedia.Org/wiki/File:Diagram_of_the_human_heart.svg 3 - Wikipedia, copyright image for any use. dextro-Transposition of the great arteries: http://en.wikipedia.0rg/wiki/File:D-TGA.jpg 4 - Wikipedia, public domain image. Hypoplastic left heart syndrome: http://en.wikipedia.org/wiki/Hypoplastic_left_heart_syndrome 5 - Wikipedia Tricuspid Atresia: http://en.wikipedia.Org/wiki/File:Tricuspid_atresia.svg 6 - Wikipedia, public domain image. Tetralogy of Fallot: http://en.wikipedia.org/wiki/Tetralogy_of_Fallot 7 - Flickr Creative Commons, attribute only search. Just a reminder of the long cold winter we had , uploaded by "Per Ola Wber~ Powi" on July 5, 2010. http://www.flickr.com/photos/powi/4762908073/ 8 - Flickr Creative Commons, attribute only search. Spring Blossoms, uploaded by "Noel Zia Lee" on March 8, 2007. http://www.flickr.com/photos/noelzialee/414585445/ 9 - Flickr Creative Commons, attribute only search. Oh Summer..., uploaded by "bark" on December 5, 2009. http://www.flickr.com/photos/barkbud/4160654917/ 10 - Flickr Creative Commons, attribute only search. Autumn Stream, uploaded by "digitalART2" on December 8, 2007. http://www.flickr.com/photos/digitalart/2095802085/ 11 - Flickr Creative Commons, attribute only search. Lettuce and fertilizer tanks, uploaded by "benketaro" on September 13, 2009. http://www.flickr.com/photos/misskei/3918032323/ 12 - From original bulletin, 2001. 13 - Baltic Agricultural run-off Action Programme, http://www.baap.lt/codes_gap/lithuania/chapter_2.htm 14 - Wkipedia public domain image from the USDA. Riparian buffer on Bear Creek in Story County, Iowa. http://en.wikipedia.0rg/wiki/File:Riparian_buffer_0n_Bear_Creek_in_St0ry_C0unty,_lowa.JPG 15 - Department of Soil and Water Conservation, Punjab. Laser Leveling: Resource Conservation through Laser Level- ing. http://dswcpunjab.gov.in/contents/data_folder/Laser_Level.htm Back Cover - From original bulletin, 2001. ------- Source Water Protection Practices Bulletin Managing Agricultural Fertilizer Application to Prevent Contamination of Drinking Water The mission of EPA is to protect human health and to safeguard the natural environment — air, water and land — upon which life depends. USEPA East (EPAEast) [Old ICC Building] 1201 Constitution Avenue. Washington, DC 20004 United States Environmental Protection Agency Office of Water (4606) EPA ### ### ### ### wwnv. epa.gov/ safewater August 2010 ------- |