NATURAL RESOURCES CONSERVATION SERVICE CONSERVATION PRACTICE STANDARD NUTRIENT MANAGEMENT

590-1 NATURAL RESOURCES CONSERVATION SERVICE CONSERVATION PRACTICE STANDARD NUTRIENT MANAGEMENT (Acre) CODE 590 DEFINITION Managing the amount, source, placement, form and timing of the application of plant nutrients and soil amendments PURPOSE To budget and supply nutrients for plant production To properly utilize manure or organic byproducts as a plant nutrient source To minimize agricultural nonpoint source pollution of surface and groundwater resources To protect air quality by reducing nitrogen and or particulate emissions to the atmosphere To maintain or improve the physical, chemical and biological condition of soil CONDITIONS WHERE PRACTICE APPLIES This practice applies to all lands where plant nutrients and soil amendments are applied. CRITERIA General Criteria Applicable to All Purposes Nutrient management plans developed under this standard shall comply with all applicable Federal, State and local laws, regulations and policies, including but not limited to the following. NRCS General Manual, Title 190, Part 402, Ecological Sciences, Nutrient Management Policy NRCS Colorado Field Office Technical Guide (FOTG) NRCS National Planning Procedures Handbook Colorado Dept. of Public Health and Environment, Water Quality Control Commission, Regulation 61, Colorado Discharge Permit System, 2004, as amended Colorado Dept. of Public Health and Environment, Water Quality Control Commission Regulation 64, Biosolids Regulation, 2003, as amended Colorado Dept. of Public Health and Environment, Water Quality Control Commission Regulation 81, Animal Feeding Operations Control Regulation, 2004, as amended Colorado Dept. of Public Health and Environment, Water Quality Control Commission Regulation 84, Reclaimed Domestic Wastewater Control Regulation, 2003, as amended Plans for nutrient management that are elements of more comprehensive conservation plans shall recognize and be compatible with other requirements of the conservation plan. Plans for nutrient management shall specify the source, amount, timing and method of application of nutrients on each field or treatment unit to achieve realistic production goals while minimizing phosphorus and nitrogen movement to surface and groundwater. Establish realistic yield goals based on soil productivity information, historical yield data, climatic conditions, level of management, local research on similar soils and cropping systems, and soil and manure or organic by-product analysis. Use a 5-year average yield + 5 percent for exceptional growing conditions if historical yield data is available. Use industry yield recommendations for new crops or varieties until documented yield information is available. Conservation practice standards are reviewed periodically, and updated if needed. To obtain the current version of this standard, contact the Natural Resources Conservation Service.

2-590 Develop a complete nutrient budget for nitrogen, phosphorus and potassium for each field or treatment unit for the rotation or cropping sequence that considers realistic yield goals and all potential sources of nutrients including, but not limited to, animal manure and organic byproducts, process wastewater, commercial inorganic fertilizer, crop residues, legume credits and irrigation water nitrate. Install erosion, runoff and water management controls, as needed, on fields where nutrients are applied. Certification A Certified Nutrient Management Specialist must approve and review all plans for nutrient management. Certified Nutrient Management Specialists are required to hold current certification through the American Society of Agronomy s Colorado Certified Crop Adviser, Certified Professional Agronomist, Certified Professional Crop Scientist/Specialist or Certified Professional Soil Scientist/Classifier Programs, or the National Association of Independent Crop Consultants Certified Professional Crop Consultants Program. Include the Certified Nutrient Management Specialist s certifying organization, certification number and expiration date, with all nutrient management plan review and approval signatures. Soil Sampling and Laboratory Analysis Base nutrient management plans on current soil test results developed in accordance with Colorado State University (CSU) guidance or standard industry practice, if recognized by CSU. Current soil tests are those that are no older than five years. Use new soil tests less than one year old for initial plan development. Collect and prepare soil samples for analysis according to CSU guidance or standard industry practice, if recognized by CSU. For soil test analyses and recommendations, use laboratories accepted in one or more of the following programs. State Certified Programs The North American Proficiency Testing Program (Soil Science Society of America) Laboratories recognized by CSU Analyze soil samples for all nutrients included in the nutrient management plan. For monitoring or amending the annual nutrient budget, request analysis for ph, electrical conductivity and soil organic matter as well as nitrogen, phosphorus and potassium. For soil test phosphorus, sample only the top 2 to 3 inches of the root zone for continuous no-till cropland, hayland and pastures, and the top 8 to 12 inches for tilled cropland. Use the Bray P1 phosphorus extraction method for acidic or low ph soils, and the Olsen (NaHCO 3 ) or AB-DTPA phosphorus extractions for soils with a ph greater than 6.5. The Mehlich 3 phosphorus extraction method is applicable for both low and high ph soils. Plant Tissue Testing Follow CSU guidance and recommendations for tissue sampling and analysis. Nutrient Application Rates Apply soil amendments as needed to adjust soil ph to the specific range required by the crop for optimum availability and utilization of nutrients. Base nutrient application rates on CSU recommendations or standard industry practice, if recognized by CSU, considering current soil test results, realistic yield goals, site conditions and producer management capabilities. If CSU does not provide the fertility recommendations needed, base application rates on realistic yield goals and crop nutrient removal. Determine nutrient application rates based on the following guidance. Nitrogen Application Plan nitrogen application rates to match the recommended rates as closely as possible, except when manure or organic by-products are a source of nutrients. For manure or organic byproducts, refer to the Additional Criteria to Properly Utilize Manure or Organic By- Products listed below. Phosphorus Application - Plan phosphorus application rates to match the recommended rates as closely as possible, except when manure or organic by-products are a source of nutrients. For manure or organic byproducts, refer to the Additional Criteria to Properly Utilize Manure or Organic By- Products listed below.

590-3 Potassium Application Do not apply excess potassium when it can cause unacceptable nutrient imbalances in crops or forages. If forage quality is an issue associated with excess potassium applications, see CSU Fact Sheet No. 0.116, Plant Analysis, for plant sampling and analysis guidance. Other Plant Nutrients Plan application rates for other nutrients according to CSU guidance or standard industry practice, if recognized by CSU. Starter Fertilizers Plan starter fertilizer applications containing nitrogen, phosphorus and potassium according to CSU guidance or standard industry practice, if recognized by CSU. Include starter fertilizer applications in the nutrient budget. Nutrient Application Timing Match the timing and methods of nutrient application (particularly nitrogen) as closely as possible with plant nutrient uptake requirements of the crop to be grown, considering cropping system limitations, weather and climatic conditions, and field accessibility. Nutrient Application Methods Do not apply nutrients to frozen, snow-covered or saturated soil if a potential risk for off-site runoff exists. When applying nutrients with irrigation water, plan and implement the Irrigation Water Management (Code 449) Conservation Practice Standard to decrease non-point source pollution of surface and groundwater resources. Environmental Risk Assessments Risk assessments for nitrogen leaching and or phosphorus runoff are required in the following situations. 1. A risk assessment for phosphorus runoff is required when plans include manure or organic by-product applications. Use the Colorado Phosphorus Index, Version 3, 2005, to complete the risk assessment. 2. Risk assessments for nitrogen leaching and or phosphorus runoff are required for fields or treatment units located in Hydrologic Unit Areas designated as impaired for nutrients. Use the Colorado Nitrogen Leaching Index, Version 2, 2005, and or the Colorado Phosphorus Index, Version 3, 2005, to complete the appropriate risk assessment(s) for the designated impairment(s). 3. Risk assessments for both nitrogen leaching and phosphorus runoff are required for all fields or treatment units included as land application sites in a Comprehensive Nutrient Management Plan. Use the Colorado Nitrogen Leaching Index, Version 2.0, 2005, and the Colorado Phosphorus Index, Version 3, 2005, to complete the risk assessments. Complete risk assessments at a frequency that corresponds to the soil test cycle, not to exceed 5 years. When environmental risk assessments are required, the nutrient management plan shall include a record of the assessment rating for each field, sub-field or treatment unit, and information about conservation practices and management activities that when applied, can decrease the potential for nutrient transport from the site. Discuss risk assessment results and recommendations to decrease nutrient transport with the producer during development of the nutrient management plan. Additional Criteria to Properly Utilize Manure or Organic By-Products as a Plant Nutrient Source Nutrient management plans that include manure or organic by-products must identify the land base acreage required to enable plan implementation based on phosphorus, even if initial implementation is on a nitrogen basis. Refer to the Colorado Nutrient Management Conservation Practice Job Sheet, Code 590, 2005 or CSU Cooperative Extension Bulletin 568A, Best Management Practices for Manure Utilization, 1999 for land base acreage requirement calculation procedures. Estimate the nutrient content of manures and organic by-products prior to land application. Base estimates on laboratory analysis, acceptable book values or records for the operation if they accurately estimate the nutrient content of the manure or organic by-product. Book values for manure nutrient content recognized by Colorado NRCS are included in the Agricultural Waste Management Field Handbook, Chapter 4, CSU Cooperative Extension Bulletin 568A, Best Management Practices for Manure Utilization, 1999, and the Colorado Nutrient Management, 590 Job Sheet.

4-590 Nutrient Application Rates The application rate (in/hr) for liquid manure and or process wastewater applied with irrigation water shall not exceed the intake rate or infiltration capacity of the soil. For each application, the total amount applied including liquid manure and or process wastewater plus irrigation water, shall not exceed the water holding capacity of the soil for the active root zone. Base application rates for manure and organic by-products on the following guidance. Nitrogen Application Use the Colorado Phosphorus Index (COPI), Version 3.0, 2005 to determine when to base application rates on crop nitrogen or phosphorus requirements, or no application. For fields with Low or Medium COPI risk ratings, base nitrogen application rates on current soil test recommendations or crop removal, considering the manure or organic by-product nitrogen concentration and appropriate mineralization rates. For fields with High COPI risk ratings where application rates are restricted to crop phosphorus requirements, application of additional inorganic commercial nitrogen may be required to meet crop requirements. Application of manure or organic by-products to legumes at rates equal to the estimated annual removal of nitrogen in harvested plant biomass is permissible provided the COPI risk rating is Low or Medium. Phosphorus Application - The planned rates of application shall be consistent with the field-specific COPI risk rating. For fields with High COPI risk ratings where application rates are restricted to crop phosphorus requirements, base phosphorus application rates on current soil test recommendations or crop removal considering the manure or organic byproduct phosphorus concentration and appropriate mineralization rates. A single application of manure or organic byproduct applied at a multi-year phosphorus rate is permissible if the COPI Risk Rating for the field is Low or Medium. The multi-year application rate shall be equal to the recommended phosphorus application, or estimated phosphorus removal in harvested plant biomass, for the crop rotation or multiple years in the cropping sequence. When planning multi-year phosphorus applications, the application rates shall: Not exceed the recommended nitrogen application rate during the year of application, or; Not exceed the estimated nitrogen removal in harvested plant biomass during the year of application when there is no recommended nitrogen application, and; Not be made on sites considered vulnerable to off-site phosphorus transport, unless appropriate conservation practices, best management practices or management activities are implemented to decrease the COPI Risk Rating to Medium or Low. Do not apply additional manure, organic byproduct or process wastewater to sites that receive multi-year phosphorus applications unless a new soil test, less than one year old, and a current COPI risk assessment indicate the risk remains Medium to Low. Comprehensive Nutrient Management Plans When a nutrient management plan is a component of a Comprehensive Nutrient Management Plan (CNMP), manure and organic by-product analysis for nitrogen, phosphorus and potassium content is required annually for each manure containment structure. This includes structures for both dry and liquid materials. CNMP land application areas must meet Colorado NRCS Quality Criteria for nutrients and organics in surface and groundwater. This requires a Low or Medium environmental risk assessment rating for phosphorus runoff and nitrogen leaching for each field or treatment unit. See the Environmental Risk Assessment section of this standard listed above for additional information. CNMP land application areas must also meet Colorado NRCS Quality Criteria for soil erosion by water and wind. For irrigated land application sites, plan and implement the Irrigation Water Management (Code 449) Conservation Practice Standard to minimize irrigation induced soil erosion.

590-5 Setback Requirements A setback is a specified distance from a land application area to waters of the state, or potential conduits to waters of the state. Setback requirements are determined as a function of the type of animal feeding operation. All Animal Feeding Operations Based on existing physical conditions and site constraints, separate eroded soil and manure particles from field runoff with edgeof-field grassed filter strips, filter fences or straw bales. Maintain a no application buffer area around water wells sufficient to prevent the possibility of waste transport to groundwater via the well or well casing. Concentrated Animal Feeding Operations Do not apply manure, organic by-products or process wastewater within 150 feet of domestic water supply wells, or within 300 feet of community domestic water supply wells. Large Concentrated Animal Feeding Operations Do not apply manure, organic by-products or process wastewater within 100 feet of any down gradient surface waters, open tile-line intake structures, sinkholes, agricultural wellheads or other conduits to surface waters. As a setback alternative, a filter strip with a minimum flow length of 35 feet, where manure, organic by-products and process wastewater are not applied, may substitute for the 100-foot setback. Refer to the Colorado Filter Strip Conservation Practice Standard, Code 393 for additional criteria and planning requirements. Heavy Metals Monitoring When sewage sludge or biosolids are applied, monitor the accumulation of potential pollutants in the soil including arsenic, cadmium, copper, lead, mercury, molybdenum, nickel, selenium and zinc, in accordance with the US Code Reference 40 CFR 503. Biosolids For biosolids applications, refer to the Colorado Dept. of Public Health and Environment, Water Quality Control Commission Regulation 64, Biosolids Regulation, 2003, as amended, and USEPA Region 8 Biosolids General Permit, August 2002 for permit requirements, soils and biosolids sampling requirements, application site soil test phosphorus limitations, setback requirements, heavy metals loading restrictions and monitoring requirements. Additional Criteria to Minimize Agricultural Non-point Source Pollution of Surface and Groundwater Resources Complete assessments for the potential of phosphorus transport and or nitrogen leaching for all fields or treatment units located in Hydrologic Unit Areas with identified or designated nutrient-related water quality impairments. Use the Colorado Phosphorus Index, Version 3.0, 2005 and or the Colorado Nitrogen Leaching Index, Version 2, 2005 to make the appropriate risk assessment(s). Risk assessment scores of Low or Medium are required for both phosphorus runoff and nitrogen leaching to meet Colorado NRCS Quality Criteria for nutrients and organics in surface and groundwater. Discuss risk assessment results and recommendations with the producer, and plan and implement practices and or management activities to decrease the potential risk of phosphorus and or nitrogen movement from the field. Additional Criteria to Protect Air Quality by Reducing Nitrogen and/or Particulate Emissions to the Atmosphere Incorporate manure, organic by-products and inorganic commercial fertilizers into the soil within 24 hours of application, unless the application site has perennial vegetation or is no-till cropland. Apply liquid manure or process wastewater with irrigation equipment when there is high humidity, little or no wind, no predicted rainfall and or when there are other conditions to minimize volatilization losses to the atmosphere. Document site-specific climate conditions before, during and after applications, in the nutrient management plan. Handle and apply poultry litter or other dry types of manure or organic by-products when weather conditions are calm to decrease the potential for blowing particulate emissions into the atmosphere. Document the basis for applying manure under these conditions in the nutrient management plan.

6-590 Additional Criteria to Maintain or Improve the Physical, Chemical and Biological Condition of the Soil Apply nutrients in ways that will not degrade soil structure, chemical properties or biological condition. Minimize the use of nutrient sources with high salt content, or develop plans to actively manage (e.g. leaching) the applied salts below the crop root zone. Do not apply nutrients to flooded or saturated soils when the potential for soil compaction and rut creation is high. CONSIDERATIONS Excessive levels of some nutrients can induce deficiencies of other nutrients. Plan and implement additional conservation practices such as the following, to decrease erosion, improve soil nutrient and water storage, infiltration, aeration, tilth, diversity of soil organisms and to protect or improve water and air quality. Anionic Polyacrylamide Erosion Control (450); Conservation Cover (327); Conservation Crop Rotation (328); Contour Buffer Strips (332); Contour Farming (330); Cover Crop (340); Cross Wind Ridges (589A); Cross Wind Trap Strips (589C); Field Border (386); Filter Strip (393); Grassed Waterway (412); Herbaceous Wind Barriers (603); Irrigation Water Management (449); Residue Management (329A, 329B, or 329C, and 344); Riparian Forest Buffer (391); Riparian Herbaceous Cover (390); Stripcropping (585), and; Terrace (600) Use deep-rooted cover crops such as winter rye, when practicable, to utilize and recycle residual soil nitrogen. Use application methods and timing to decrease the risk of transporting nutrients to surface and groundwater, or into the atmosphere. Suggestions include: Split apply nitrogen to provide nutrients at times of maximum crop utilization; Avoid winter nutrient applications for spring seeded crops; Band apply phosphorus near the seed row; Apply nutrient materials uniformly or as prescribed by precision agricultural techniques; Incorporate land applied manures and organic by-products immediately, and; Delay field applications of manures and organic by-products if precipitation capable of producing runoff and erosion is predicted within 24 hours of the planned application. Maintain minimum application setback distances from environmentally sensitive areas such as sinkholes, wells, gullies, ditches, surface inlets or rapidly permeable soil areas. Minimize potential problems from odors associated with land application of animal manures, especially when applied near or upwind of residences. Conduct a cultural resources site review to minimize the potential to affect National Register listed or eligible cultural resources. Review nutrient budgets annually to determine if changes are desirable (or needed) for the next planned crop. On sites where there are special environmental concerns, consider other soil sampling techniques such as the following to gather additional information. Soil profile sampling for nitrogen, Pre-Sidedress Nitrogen Test (PSNT), Pre-Plant Soil Nitrate Test (PPSN) or soil surface sampling for phosphorus accumulation or ph changes Consider ways to modify the chemistry and or physical properties of animal manure, including modification of the animal s diet, to decrease the manure nutrient content and enhance the producer s ability to manage manure effectively. When applying liquid manure with sprinkler irrigation, drop nozzles can decrease the potential for nitrogen volatilization. To decrease nitrogen volatilization from liquid manure applied with flood irrigation, apply under a crop canopy. The combined effects of nutrient application methods and tillage operations can effect emissions of greenhouse gasses such as carbon dioxide (CO 2 ), methane (CH 4 ) and nitrous oxide (N 2 O), and the potential to sequester carbon in the soil profile.

590-7 PLANS AND SPECIFICATIONS Prepare plans and specifications for each field or treatment unit according to the Criteria, Considerations and Operation and Maintenance sections of this standard. Specifications shall describe the requirements for applying this practice to meet the intended purpose. Complete a Colorado Nutrient Management 590 Job Sheet, 2005, to document plans and specifications developed for each field or treatment unit for each year that Nutrient Management will be planned and applied. The following components shall be included in the nutrient management plan, as applicable. 1. Aerial site photographs or field maps, and a soils map for the site 2. Current and or planned plant production sequence or cropping rotation 3. Results of soil, plant, irrigation water, manure and organic by-product sample analyses 4. Realistic yield goals for the crops in the rotation, and how the yield goals were determined 5. Quantification of all important nutrient sources 6. Recommended nutrient application rates, timing, form, and methods of application and incorporation 7. Location of designated sensitive areas or resources and the associated nutrient management restrictions and setbacks, delineated on aerial site photographs or field maps 8. Guidance for implementation, operation and maintenance activities and recordkeeping 9. A complete nutrient budget for nitrogen, phosphorus and potassium for each field or treatment unit for the rotation or cropping sequence When plans for nutrient management are developed and implemented in a way that results in expected increases in soil phosphorus levels, document the following information in the plan. The soil test phosphorus levels at which it may be desirable to convert to a phosphorus based application rate for manure and or organic by-products The relationship between elevated soil test phosphorus levels and the potential for phosphorus transport from the field, and The potential for soil phosphorus drawdown or utilization, from the production and harvesting of crops When applicable, plans shall include other practices or management activities as determined by specific regulation, program requirements or producer goals. In addition to the requirements described above, plans for nutrient management shall also include the following information. Discuss the relationship between nitrogen and phosphorus transport and water quality impairment. The discussion about nitrogen should include information about nitrogen leaching into shallow ground water and the potential health impacts. The discussion about phosphorus should include information about accumulation in the soil, the increased potential for phosphorus transport in soluble form, and the types of water quality impairments that could result from phosphorus movement into surface water bodies. Discuss how the plan is intended to prevent the nutrients (nitrogen and phosphorus) supplied for production purposes from contributing to water quality impairment. State that the plan was developed based on the requirements of the current CO NRCS Nutrient Management Standard and all applicable Federal, State and local laws, regulations and policies, and that a change in any of these requirements may necessitate a revision of the plan. State the basis for application recommendations for liquid and solid forms of manure or organic by-products, and inorganic commercial fertilizer relative to decreasing the potential for nitrogen or particulate emissions to the atmosphere.

8-590 OPERATION AND MAINTENANCE The owner/client is responsible for safe operation and maintenance of this practice including all equipment. Address the following elements in the Operation and Maintenance component of the plan. 1. Schedule periodic plan reviews to consider adjustments or modifications. If a review indicates a revision of the plan is required, a Certified Nutrient Management Specialist must approve the revised plan. Complete a thorough review of the nutrient management plan with new soil tests on a regular cycle, not to exceed 5 years. Document the results of such reviews in the plan including the reviewing Certified Nutrient Management Specialist s name, certifying organization, certification number and expiration date. 2. Protect fertilizer and organic by-product storage facilities from weather and accidental leakage or spillage. 3. Calibrate application equipment to ensure uniform distribution of material at planned rates. 4. Document the actual rates at which nutrients are applied. When actual rates differ from or exceed the recommended and planned rates, indicate the reasons for the differences. 5. Maintain the following records, as applicable, to document plan implementation. Soil test results and nutrient application recommendations Quantities, analyses and sources of nutrients applied Dates and methods of nutrient applications; Weather conditions at the time of application and amount of time until a rainfall event occurred after application (applicable when air quality issues are being addressed in the plan) Crops planted, planting and harvest dates, yields, and amounts of crop residues removed Results of irrigation water, plant, and organic by-product analyses Results of risk assessments completed for phosphorus and nitrogen transport The land base requirement calculation for plan implementation on both an N and P basis, when manure or organic byproducts are a nutrient source, and Plan review dates and the name of the nutrient management specialist that conducted the review including their certifying organization, certification number and expiration date, and any resulting adjustments or recommendations. Maintain records for five years, or for a period longer than five years if required by other Federal, State or local law or regulation or program or contract requirements. Protect workers from and avoid unnecessary contact with inorganic commercial fertilizers, manures or organic by-products. Use protective clothing when working with plant nutrients. Additional precautions and protective equipment are required for handling anhydrous ammonia, and organic wastes stored in unventilated enclosures. Dispose of materials generated by cleaning nutrient application equipment properly. Collect and store excess materials, or field-apply in an appropriate manner. Do not apply excess materials on areas with high potential risks for runoff and leaching. Dispose of or recycle nutrient containers according to State and local guidelines and regulations. REFERENCES Colorado Dept. of Public Health and Environment, Water Quality Control Commission Regulation 61, Colorado Discharge Permit System, 2004. CDPHE, WQCD, Denver, CO. http://www.cdphe.state.co.us/op/regs/waterregs/1 00261wqccdischargepermitsystem604.pdf Colorado Dept. of Public Health and Environment, Water Quality Control Commission Regulation 64, Biosolids Regulation, 2003. CDPHE, WQCD, Denver, CO. http://www.cdphe.state.co.us/op/regs/waterregs/1 002642.pdf

590-9 Colorado Dept. of Public Health and Environment, Water Quality Control Commission Regulation 81, Animal Feeding Operations Control Regulation, 2004. CDPHE, WQCD, Denver, CO. http://www.cdphe.state.co.us/op/regs/waterregs/1 00281confinedanimalfeedingregs604.pdf Colorado Dept. of Public Health and Environment, Water Quality Control Commission Regulation 84, Reclaimed Domestic Wastewater Control Regulation, 2004. CDPHE, WQCD, Denver, CO. http://www.cdphe.state.co.us/op/regs/waterregs/1 00284wqccreclaimeddomesticwastewater0604.p df Colorado Field Office Technical Guide, Section IV. Irrigation Water Management 449 Conservation Practice Standard. 2002. USDA, NRCS, Lakewood, CO. http://efotg.nrcs.usda.gov/references/public/co/4 49-CO.pdf Colorado Field Office Technical Guide, Section IV. Nutrient Management 590 Conservation Practice Job Sheet. 2005. USDA, NRCS, Lakewood, CO. http://efotg.nrcs.usda.gov/references/public/co/c O590_JS.xls Colorado Field Office Technical Guide, Section I. Agronomy Technical Note No. 92. 2000. Manure Spreader Calibration. USDA, NRCS, Lakewood, CO. 61.p df Colorado Field Office Technical Guide, Section I. Agronomy Technical Note No. 95. 2005. Colorado Phosphorus Index Risk Assessment, Ver. 3.0. USDA, NRCS, Lakewood, CO. http://efotg.nrcs.usda.gov/references/public/co/c OATN_95v3.pdf Colorado Field Office Technical Guide, Section I. Agronomy Technical Note No. 97. 2005. Colorado Nitrogen Leaching Index Risk Assessment, Ver. 2.0. USDA, NRCS, Lakewood, CO. http://efotg.nrcs.usda.gov/references/public/co/c OATN_97v2.pdf National Planning Procedures Handbook, Amendment 4. 2003. USDA, NRCS, Washington D.C. http://policy.nrcs.usda.gov/scripts/lpsiis.dll/h/h_1 80_600.htm NRCS General Manual, Title 190, Part 402, Ecological Sciences, Nutrient Management Policy. 1999. USDA, NRCS, Washington D.C. http://www.nrcs.usda.gov/technical/ecs/nutrient/ gm-190.html Waste Management Field Handbook. Chapter 6. 1992. USDA, SCS, Washington, D.C. http://www.info.usda.gov/ced/ftp/ced/neh651- ch6.pdf Colorado State University Cooperative Extension Crop Publications, Fort Collins, CO. No. XCM-172, Best Management Practices for Nitrogen Fertilization, 1994. http://www.ext.colostate.edu/pubs/crops/xcm 172.pdf No. XCM-175, Best Management Practices for Phosphorus Fertilization, 1994. http://www.ext.colostate.edu/pubs/crops/xcm 175.pdf No. XCM-178, Best Management Practices for Pesticide and Fertilizer Storage and Handling, 1994. http://www.ext.colostate.edu/pubs/crops/xcm 178.pdf No. 568A, Best Management Practices for Manure Utilization, 1999. http://www.cerc.colostate.edu/titles/568a.htm l No. 0.116, Plant Analysis, 2004. http://www.ext.colostate.edu/pubs/crops/001 16.pdf No. 0.500, Soil Sampling, 1997. 00.pdf No. 0.501, Soil Testing, 1999. 01.pdf No. 0.502, Soil Test Explanation, 1999. 02.pdf No. 0.507, Soil, Water and Plant Testing, 2001. 07.pdf No. 0.509, Vegetable Fertilizer Guide 1993. 09.pdf

10-590 No. 0.512, Fertigation, 1992. 12.pdf No. 0.514, Nitrogen and Irrigation Management, 1999. 14.pdf No. 0.520, Selecting an Analytical Laboratory, 2000. 20.pdf No. 0.534, Fertilizing Spring-Seeded Small Grains, 1996. 34.pdf No. 0.535, Fertilizing Mountain Meadows, 1996. 35.pdf No. 0.536, Fertilizing Revegetated Disturbed Lands, 1996. 36.pdf No. 0.537, Fertilizing Alfalfa and Grasses, 1996. 37.pdf No. 0.538, Fertilizing Corn, 1996. 38.pdf No. 0.539, Fertilizing Dry Beans, 1996. 39.pdf No. 0.540, Fertilizing Grain and Forage Sorghums, 1996. 40.pdf No. 0.541, Fertilizing Potatoes, 1996. 41.pdf No. 0.542, Fertilizing Sugarbeets, 1996. 42.pdf No. 0.543, Fertilizing Sunflowers, 1996. 43.pdf No. 0.544, Fertilizing Winter Wheat, 1996. 44.pdf No. 0.545, Zinc and Iron Deficiencies, 1992. 45.pdf No. 0.546, Organic Materials as Nitrogen Fertilizers, 1996. 46.pdf No. 0.547, Biosolids Recycling on Crop- and Rangeland, 1994. 47.pdf No. 0.548, Fertilizer Cost Calculations, 1995. 48.pdf No. 0.550, Nitrogen Sources and Transformations, 1996. 50.pdf No. 0.553, Fertilizer Practices and Efficiency, 1999. 53.pdf No. 0.555, Grain Protein Content and N Needs, 1992. 55.pdf No. 0.560, Cattle Manure Application Rates, 2000. 60.pdf No. 0.561, Manure Spreader Calibration, 1999. 61.pdf No. 0.565, Update on Manure and Effluent Recommendations, 2000. 65.pdf No. 1.222, Liquid Manure Application to Cropland, 1998. http://www.ext.colostate.edu/pubs/livestk/012 22.pdf No. 1.223, Liquid Manure Application Methods, 1998. http://www.ext.colostate.edu/pubs/livestk/012 23.pdf