• Topics: Soil and Water Science  |  Hochmuth, George J  |  Nell, Terril  |  Sartain, Jerry B  |  Cisar, John L  |  Trenholm, Laurie  |  Unruh, Joseph Bryan  |  Dukes, Michael D  |  Lawn Fertilizer  |  Environmental Laws and Regulations 

Unintended Consequences Associated with Certain Urban Fertilizer Ordinances¹

A publication from the University of Florida, IFAS, Center for Landscape Conservation and Ecology, Soil and Water Science Department, The Department of Environmental Horticulture, and The Department of Agricultural and Biological Engineering.

Introduction

Total nutrient loads have been increasing over the last decades in many water bodies in Florida. Increased nutrient loading can come from many sources, including natural, and sources related to man's activities on land and in the water. Surface runoff and leaching to groundwater, particularly of nitrogen (N) and phosphorus (P), from land-based sources, including residential lawns and landscapes, have been implicated in the degradation of water bodies in urban coastal Florida. For example, Red Tide and other algal-bloom and eutrophication problems in coastal waters have sometimes been thought to be related to nutrient runoff from land (Anderson et al., 2002; Heisler et al., 2008). Total Maximum Daily Loads (TMDLs) are established by the Florida Department of Environmental Protection (FDEP) to deal with degraded water bodies. TMDLs have been established for several areas in the state and others will follow. Where TMDLs have been established, a Basin Management Action Plan (BMAP) guides nutrient management at the sources, and water body cleanup to achieve the TMDL goal.

Nutrients are applied as fertilizer to plants to achieve a certain goal, i.e., increased yields, improved fruit quality, improved human health characteristics of food plants, more beautiful ornamental plants, healthier turfgrass to control runoff, etc. Fertilizer should be thought of as supplementing the native nutrients already in the soil to help plants perform better. Using fertilizer correctly for environmental protection and crop performance involves a careful balance of factors such as the correct amount, appropriate timing and placement of applications, best selection of nutrients needed, best sources and forms of the fertilizers, and optimum water (irrigation) management. Amounts of fertilizers in the non-agricultural area (nursery, golf courses, and retail) have been declining over recent years (FDACs, 2009). Greatest efficiency, and minimized fertilizer nutrient loss occur where the crop or plant nutrient requirements are understood (how much fertilizer is needed to supplement the nutrients in the soil?), and where best management practices are followed so the plant receives the benefit of the fertilizer and negligible amounts are lost. Our goals should be to use appropriate nutrient management practices and guidelines, where appropriate, to keep the nutrient losses to a very minimum that preserves the intended use of the water bodies. Removal of nutrients from an impaired water body is a very costly process.

Counties and local municipalities in Florida are taking several approaches, including voluntary and non-voluntary means, to comply with the TMDL limits. Fertilizer ordinances are being used as a regulatory approach in several counties and municipalities. Some early ordinances were adopted in the Town of Wellington, St. Johns County, and Sarasota County (see reference list). A more recently proposed model ordinance, for potential wide adoption by counties and municipalities in the Tampa Bay Region, was developed by the Tampa Bay Estuary Program (Tampa Bay Estuary Program, 2008). A good coverage of the history and development of fertilizer ordinances in Florida can be found in Hartman et al. (2008). These ordinances include many logical and science-based aspects, such as applying fertilizer at recommended rates, using appropriate fertilizer sources including controlled-release fertilizers, soil testing for P, removing fertilizer, turf clippings, and plant materials from impervious surfaces, implementing fertilizer-free zones near water bodies, and using appropriate irrigation practices.

Sometimes well-intentioned guidelines, rules, and ordinances may lead to unintended consequences that were not foreseen in the rule-making process. In the case of fertilizer ordinances, the unintended consequence, as used in this fact sheet, could be an inadvertent increase in potential nutrient losses to the environment as a result of a well-intentioned ordinance.

One regulatory approach that has been popular in the ordinances of some counties and municipalities is a restricted period (also called a "black-out" period) where N and P fertilization of turfgrass is prohibited during the summer "rainy" period, typically June 1 through September 30. The underlying reasoning behind the fertilizer restricted period is concern over fertilizer runoff and leaching during frequent and heavy rainfall events in the summer. The research on this subject, however points to possible problems associated with severely restricting fertilizers on turf and landscape plants during their most active growing period on sandy and/or compacted soils with low nutrient- and water-holding capacities. These unintended consequences could result in increases in nutrient application, increases in nutrient leaching and run-off into water bodies, and increased soil erosion, among other problems. This paper discusses the research behind turfgrass growth, biology, and ecology, and soil nutrient cycling in the lawn. The unintended consequences of fertilizer ordinance restricted periods are presented to open dialogue among the stakeholders in the ordinance issue and to ensure that all information is presented to completely inform the policy-making process.

The University of Florida IFAS Cooperative Extension Service has fertilization recommendations for turfgrass, and the amounts of fertilizer recommended for the summer months are the minimal amount required to maintain healthy turfgrass and minimize any losses of nutrients to the environment. The authors understand the need to properly manage nutrients in the environment and the need to apply well-thought-out and science-guided controls on fertilizer use to prevent negative impacts to our environment. We offer science-based alternatives to the strict, calendar-based (summer) fertilizer restricted period approach to encourage new habits for managing nutrients in the residential landscape and to achieve everyone's improved water quality goals.

Audience for this publication: The authors believe the information in this publication should be of interest to anyone involved in discussing the issues surrounding the use of ordinances for regulating fertilizer use on lawns and landscapes. The material in this publication is presented from a position of asking important science-based questions and pointing to some possible unintended consequences of certain ordinance language. As such, Extension takes no "sides" in the issue. Our sole objective is to make sure that science is the foundation for making policy and regulation decisions, and that all stakeholders in the issue are presented all the information in true educational format. This document is intended for use by knowledgeable and/or trained individuals in urban fertilizer and irrigation management, and in the issues regarding fertilizer regulation. It is intended for use in informing individuals and groups of individuals involved in making fertilizer rules and ordinances and in educating all stakeholders concerned about making the right decisions about nutrient management in the context of environmental protection.

Unintended consequences of a rainy-season or summer fertilization restricted or black-out period:

A calendar-based restriction of N and P fertilizer applications in the summer rainy season might appear to be a logical reaction to the problem of increased amounts of nutrients in the water bodies in urbanized areas in this state. But, does removing fertilizer from the urban landscape really achieve the goal of preventing losses of nutrients to the environment? There are several aspects of the biology of turfgrass growth, the ecology of the landscape, and nutrient cycling in the soil that point to possible unintended consequences of such a calendar-based restricted period. We are presenting the unintended consequences below along with the best science available that addresses each issue. Hopefully these questions will lead to more discussion among all stakeholders about addressing the overall best and most effective nutrient management approaches for lawn and landscapes.

Unintended consequence #1: Turfgrass not adequately fertilized will decline in vigor potentially leading to increased leaching of nutrients during the summer, and of fertilizer applied after the restricted period.

• The most active growth period for warm-season grasses is during the long, warm days of late spring and summer (Figure 1). This is the time of greatest growth and nutrient requirements for these grasses. This is also the time when the grasses have the greatest ability to take up nutrients, due to larger, denser, and more actively growing root and shoot systems. A single application of fertilizer (soluble or controlled-release), made just prior to the onset of the restricted period that complies with the amount allowed in the FDACS' Fertilizer Rule (FDACS, 2007), will not likely satisfy turfgrass growth requirements throughout the summer restricted period.

• Turfgrass needs adequate and consistent nutrition for optimal health, and healthy, actively growing turf is excellent at absorbing nutrients. The current Extension fertilizer recommendations for turfgrass, summarized by Sartain (2007) emphasize applications of controlled-release N in the summer. Recent research (Figure 1) in Florida shows little N leaching in the summer from a well-maintained lawn that is fertilized (and irrigated) according to research-based recommendations in Florida (Trenholm et al. (unpublished data); Sartain, 2009). In well-established and maintained St. Augustinegrass turf, in-organic N leaching was low with concentrations of NH₄-N and NO₃-N in drainage generally less than that reported for precipitation in southern Florida (Erickson et al., 2008). Figure 1 shows that more fertilizer is potentially lost from applications made during the year when the turfgrass is not growing as actively as it is in the summer.

• Turfgrass that does not receive adequate N and P will decline with time, leading to weaker turf with less dense root and shoot systems that are less capable of absorbing fertilizer rapidly. Warm-season turfgrass root growth typically declines in fall and winter months due to shorter days, cooler temperatures, and less sunlight (Figure 1 and Figure 2). A grass that does not receive adequate nutrition at the proper time would experience even more decline. This decline might not be immediate upon imposition of a restricted period, due to residual and native nutrients held in the soil, but would become evident in succeeding years as these nutrients are used.

• Under a restricted period of June 1^st to September 30^th, fertilizer application would be allowed after September 30^th. A problem here is that grass that has not been adequately fertilized in the summer will have decreased root and shoot systems compared with grass that has been adequately fertilized during the growing period. The normal decline of root mass under fall conditions, coupled with root decline due to a summer nutrient deficiency could lead to increased potential for nutrient leaching or runoff when fertilization resumes as the restricted period expires.

• Treating N-deficient turfgrass during a restricted period with other nutrients, such as iron or potassium to get "green-up" will not cure the underlying N deficiency and the shoot and root system will continue to decline.

Figure 1. 

Growth of warm-season turfgrass (top) and N leaching during season (bottom-after Sartain, 2009).

Figure 2. 

Root mass of warm-season turfgrass normally declines under shorter days and lower light levels of fall (Sartain, 2009).

Unintended consequence #2: Unhealthy turfgrass will decline in soil coverage, leading to more leaching, more weeds, and to more soil erosion and nutrient runoff.

• Weak turf will lead to bare-soil areas where weeds will likely invade, which may lead to an increased use of herbicides. Bare-ground patches would lead to more N leaching when fertilizer applications resume following the restricted period. Bare areas also are most prone to erosion and increased nutrient runoff from the lawn. Turfgrass acts to reduce the velocity of the runoff and also filters particulates and contaminants from the water. By reducing the velocity of the water, increased infiltration will occur resulting in groundwater recharge (Blanco-Canqui, 2003) and increased nutrient uptake by turfgrass will occur. Healthy turf captured the runoff from a 10% slope reducing the N concentration in the runoff to that in the actual rain water (Erickson et al., 2001).

• Turf establishment in new communities, those less than 3 years old, may be particularly disadvantaged by a restricted period because there would typically be poorer soil (fill) on which to establish the lawn. This would lead to weakened turf and to un-intended consequences described above. In addition there would not be adequate accumulation of grass clippings and the associated build-up of organic matter required to help the turf through a period of restricted fertilizer use. Turf is considered an effective soil anchor for good landscape design in a low-impact community.

Unintended consequence #3: A strict, calendar-based restricted period may encourage poorer fertilizer management habits.

• Individuals, with particular concerns about the long restricted period, may apply extra N fertilizer prior to the restricted period, thinking that the extra N will last throughout the restricted period. This practice could result in considerable loss of soluble N to runoff and leaching before the turfgrass has had time to take up all nutrients. Poor fertilizer habits in other parts of the year (when fertilization is allowed), such as not sweeping fertilizer and grass clippings off of impermeable surfaces, is just as likely as in the summer. Excessive leaching and/or runoff could result with excessive application of either soluble or controlled-release N products during these periods. Figure 1 shows that, when leaching is considered, the periods before and after the summer restricted period should be of at least equal concern as the actual summer period (when the turfgrass is growing and absorbing nutrients).

• If homeowners experience a decline in their turf coverage and quality in the summer due to the inability to apply N during a restricted period, then there may be additional unintended consequences, such as discrete fertilizer over-applications in an attempt to get the grass to recover rapidly. This outcome is likely, especially where ordinances cannot be enforced due to budgetary constraints.

Unintended consequence #4: Focusing solely on the summer rainy period neglects the remainder of the year when leaching and runoff also can occur, especially just before and just after the summer restricted period.

• A problem with the summer restricted period ordinance approach is that it addresses only one-third of the year. Only about 10 to 15% of all rainfall events in Florida are 1 inch or more, those most likely to result in nutrient leaching (Figure 3). There are other times in the year with these same leaching rainfall events, especially in the fall (Figure 4). An unintended consequence might be the uncontrolled fertilization by homeowners during the rest of the year to "get ready for" or to "recover from" the negative effects of the restricted period. Thus, implementation of a restricted period in fertilization maintenance of a home lawn could lead to greater overall mismanagement of fertilizers in the urban environment. Perhaps a more effective approach would be to implement already-existing best management practices year-round and educate everyone about the consequences to the environment of NOT following best management practices. This approach might include encouraging best fertilizer management especially during those periods of the year when leaching is most likely to occur.

Figure 3. 

Percentage of annual rainfall events greater than 1 inch at selected locations in Florida. Rain events separated by less than 6 hours are considered to be a single event. Period of record used: 1942-2005. The gauges analyzed contained between 28 and 64 complete years of data.

Figure 4. 

Monthly mean rainfall totals (inches) at select stations across Florida 1971-2000.

Unintended consequence #5: Focusing solely on fertilizer and neglecting irrigation management practices could lead to more leaching and runoff of nutrients.

• Any attempt to minimize N pollution from the urban landscape will be for naught if irrigation best management practices are not included in fertilizer guidelines. Automatic operation of irrigation systems during the rainy-season period (when not needed) intensifies the leaching and runoff potential. Irrigation and fertilization practices go hand-in-hand. Properly fertilized and irrigated turf is one of the most environmentally sound plant systems available. In an early study in Florida, scheduling irrigation by a moisture sensor device that canceled irrigation when the soil contained adequate moisture led to more efficient irrigation and to negligible loss of the soluble N applied (ammonium nitrate). Irrigation at 125% of evapotranspiration + rainfall resulted in loss of 50% of the applied soluble N (Snyder et al., 1984). Proper irrigation management is critical to preventing nutrient losses.

• The trend in Florida points to greater water restrictions, even during non-drought periods. Turfgrass (and other plants) stressed, due to reduced water inputs during water restriction periods (e.g., watering only on "your" day, rather than when needed), could be further stressed if there is a nutritional deficiency induced during restricted periods.

• Day-of-the-week watering restrictions may encourage over-watering on "your day." This could compound the problem of soluble fertilizer being leached when applications are being made just before, or after, the restricted period.

Additional considerations regarding urban turf irrigation as it relates to turf health and fertilization:

• Nutrient and water management are tightly linked for maintaining healthy turfgrass (Dukes et al., 2009). Proper irrigation management is needed for healthy turf and for preventing nutrient losses. An urban irrigation scheduler tool is available on the Florida Automated Weather Network (FAWN) at http://fawn.ifas.ufl.edu/tools/urban_irrigation. This tool allows a user to determine irrigation controller runtime estimates with three clicks of the computer mouse. Research has shown that using guidelines such as this tool can reduce irrigation as much as 30% (Haley et al., 2007). Better management of irrigation means less potential for nutrient losses.

• Early work with tensiometer-controlled irrigation resulted in improved water efficiencies (Snyder et al., 1984). New technology is available in the irrigation arena known as "Smart Irrigation" controllers. These irrigation controllers use inputs from the irrigated area to determine or regulate irrigation. Research in Florida on soil moisture sensor controllers has shown that irrigation savings can exceed 70% of automatic clock scheduled irrigations with a variety of controllers under normal rainfall conditions (Cardenas-Lailhacar et al., 2008; McCready et al., 2009). Savings during dry periods are less dramatic but are as much as 30-40% (McCready et al., 2009). Finally, ET (evapotranspiration) controllers have also been shown to result in savings of 43% during dry conditions (Davis et al., 2009).

Unintended consequence #6: Where reclaimed water is being used, nutrients supplied with the reclaimed water could be leached if irrigation is not properly managed. The information below is presented to make several points about relying on reclaimed water as a substitute for fertilizers during a restricted period.

Many new residential developments have made reclaimed water available for irrigating lawns and landscapes. In addition to the water for irrigation, reclaimed water is being viewed as a source of nutrients. There are challenges to using reclaimed water in the landscape, especially if reclaimed water is seen as a way to replace fertilizers in a restricted period. The data presented in Tables 1 and 2 are for illustration purposes only and are not meant to be used for estimating reductions in fertilizer, for reasons discussed below.

Considerations for the use of reclaimed water as a source of nutrients:

• In terms of reclaimed water from advanced waste water treatment facilities (AWT, limited to no more than 3.0 mg/L N and 1.0 mg/L P), the mass balance points to excessive amounts of water (> 100 inches) required to deliver even the lowest recommended amounts of N. This is due to the low concentration of N in AWT reclaimed water (Table1). Reclaimed water users should know the concentrations of nutrients in their water before determining an irrigation schedule. Concentrations of N can be greater from facilities with only secondary waste water treatment (the 20 and 30 ppm rows of data in Table 1). These are the calculated amounts of total N that may be in the reclaimed water, and the quantity of specific species of N in the reclaimed water that actually becomes available to the turfgrass is unknown. Research has not been completed to address the unknowns about N losses from reclaimed water; therefore, we cannot say for sure there is a 1:1 substitution of reclaimed water N for fertilizer N.

• Proper irrigation management with reclaimed water is required to prevent N leaching from over-application of water. Rates of reclaimed water used in irrigation should be based on the water needs of the turfgrass. Excessive irrigating with reclaimed water can result in leaching of the N contained in the reclaimed water as well as fertilizer N previously applied to the turfgrass. Irrigation with reclaimed water should be practiced with careful attention to avoiding over-irrigation, as described above in the section on irrigation.

• Proper irrigation management with reclaimed water can also reduce the over-application of P. For example in Table 2, using 30 inches of reclaimed water with 0.5 ppm P would result in the application of 0.179 lbs of P₂O₅ per 1000 sq. ft. for the year. The amount of P coming from the reclaimed water can influence the amount of fertilizer-P needed as indicated by appropriate soil testing. Many of the combinations of reclaimed water P concentrations and irrigation amounts in Table 2 would exceed the Florida Department of Agriculture and Consumers Services "Urban Turf Fertilizer Rule" (FDACS, 2007), especially where the soil tests show high levels of P already in the soil. This rule, which currently pertains to bagged fertilizer-not reclaimed water, places a limit of 0.25 lb P₂O₅ per 1000 sq. ft. per application and no more than 0.50 lb P₂O₅ per 1000 sq. ft. per year.

• Salt accumulation might become a problem for certain turfgrasses during periods of drought and result in an unhealthy turfgrass with a reduced root system which may lead to an increase in leaching of applied fertilizer nutrients.

• Automatically irrigating with reclaimed water year-round would contribute N, P, and other nutrients, during the slow-growing or dormant period of turfgrass and landscape plants, when these nutrients might not be needed by the plants.

• The specific N and P concentrations in reclaimed water are not always optimal for turfgrass requirements. For example, a homeowner may have a soil that tests high in P and therefore does not require the P from the reclaimed water. In this case, it might not be wise to use reclaimed water. The actual availability to the turfgrass of the added P in reclaimed water is governed by the soil chemical properties, which may render the P unavailable to the turfgrass. This may occur if the soil pH is too high or the soil contains high levels of iron and/or aluminum.

The University of Florida summer rainy-season N fertilizer management strategy for inclusion in a fertilizer ordinance:

The authors support good nutrient and water management practices for turf and landscape plants. Research shows turf to be very good at accumulating nutrients and mitigating leaching when actively growing in the summer. The unintended consequences described above should be of intense interest to those interested in developing ordinances for preventing nutrient pollution.

We believe there are two science-based approaches to avoid the unintended consequences of a summer restricted period described above.

One strategy would be to use the Green Industries Best Management Practices Guide (FDEP, 2008; Sartain, 2007; Trenholm, 2007) for managing fertilizers year-round. Controlled-release fertilizers are recommended for the summer, rainy period. These guidelines have been developed to provide research-based information about properly managing fertilizers and irrigation water to prevent losses of nutrients to the environment. Strong and effective education about fertilizer use is the key to any successful best management practice.

Second, if the county or municipality feels they must invoke a summer fertilizer "restricted" period, then we hope this document will assist in determining the details of the restricted period. We propose the following reasonable and workable strategy and best management practice during any summer fertilizer restricted period:

Allow application of fertilizer containing no more than 0.5 lb per 1000 sq. ft. soluble N (total N limited to 1.0 lb per 1000 sq. ft) during the summer restricted period to correct a professionally (BMP trained county agent or BMP-trained turf professional) diagnosed/predicted nitrogen deficiency in the turf. This approach is consistent with the UF/IFAS turf fertilization recommendations (Sartain, 2007; Sartain et al., 2009; Trenholm, 2007; Trenholm et al., 2009), which are based on more than 20 years of research, the Green Industries Best Management Practices Guide, the FDACS Urban Turf Rule, and the FDEP Model Turf Ordinance (FDACS, 2007; FDEP, 2008; FDEP, 2009).

Nitrogen diagnosis would be by the following standard, commonly used research color/quality rating scale (Skogley and Sawyer, 1992):

Figure 5. 

Turf visual rating of 5.5 (range of 1 to 9) corresponds to the adequate level (2.0%) of leaf N concentration.

Color is highly related to the N status of the turfgrass (Figure 5). A very good quality grass (healthy, actively growing, and good visual quality) would be one that rated 7.0 to 8.0. One that rated a nine would be very healthy but possibly somewhat excessively fertilized. Considering also environmental and economic factors, it is best to manage turf in the range of 6.0 to 7.0 (with tissue N > 2.0 %), which would be rated a "good" to "very good" quality turfgrass.

Summary/concluding comments

• UF/IFAS strongly supports using research-based science to underpin sound guidelines for protecting the environment and for providing for the enjoyment of the urban landscapes.

• • • We believe research can identify those situations where fertilizers are needed, where fertilizers are not needed, and where fertilizer losses to leaching are most likely.

    • This publication points out possible unintended consequences associated with the summer fertilizer restricted period in certain ordinances and presents science-based alternatives. We hope the publication is viewed for its intended educational purpose.

• Addressing urban fertilization practices should be a year-round process, using best management practices and effective consumer and professional education. Additional education and research is needed for best management practices for homeowners and turf professionals.

• • • Education and incentives (with accountability) have proven to achieve the best results in changing behavior. We believe good habits will come if the regulation is reasonable and defendable from a science basis, and if individuals have been properly educated about the issues and best management practices.

    • The University of Florida has published three documents containing answers to frequently-asked questions related to landscape fertilization and irrigation (Dukes et al., 2009; Sartain et al., 2009; Trenholm et al., 2009).

In summary, considerable research has been conducted on turfgrass fertilization and water management in urban environments. Much information already is embodied in best management recommendations for environmental protection and should be incorporated into fertilizer ordinances. Part of solving the water quality problems associated with urban fertilizer management is to increase the adoption of known best fertilizer and irrigation practices technologies by homeowners. Another part of solving the problem is making the solutions logical and reasonable so there is a very high likelihood of adoption. There is a strong need for all stakeholders (scientists, environmental groups, lawn, landscape, and fertilizer industries, state agencies, county BOCCs, local municipalities, and others) to work together to develop and implement a lasting solution that everyone adopts and that future generations will continue to benefit from.

References Cited

Anderson, D. M., et al. 2002. Harmful algal blooms and eutrophication: nutrient sources, composition, and consequences. Estuaries 25:704-726.

Blanco-Canqui, Humberto, Ph.D., University of Missouri - Columbia, 2003, 190 pages; AAT 3115525.

Cardenas_Lailhacar, B. and M.D. Dukes, and G.L. Miller. 2008. Sensor-based automation of irrigation on Bermudagrass during wet weather conditions. Journal of Irrigation and Drainage Engineering 134(2):120-128.

Davis, S.L., M.D. Dukes, and G.L. Miller. 2009 (in review). Landscape irrigation by evaporation-based irrigation controllers under dry conditions in Southwest Florida. Agricultural Water Management.

Dukes, Michael D., Laurie E. Trenholm, Ed Gilman, Chris J. Martinez, John L. Cisar, Thomas H. Yeager. 2009. Frequently Asked Questions about Landscape Irrigation for Florida-Friendly Landscaping Ordinances. Fla. Coop. Ext. Publication #ENH1114. http://edis.ifas.ufl.edu/WQ142.

Erickson, J. E., J. L. Cisar, J. C. Volin, and G. H. Snyder. 2001. Comparison of nitrogen runoff and leaching between newly established St. Augustinegrass turf and an alternative residential landscape Crop Sci. 41: 1889-1895.

Erickson, J. E., J. L. Cisar, G. H. Snyder, D. M. Park, and K. E. Williams. 2008. Does a mixed-species landscape reduce inorganic-nitrogen leaching compared to a conventional St. Augustinegrass lawn? Crop Science, Vol. 48:1-9.

Florida Department of Environmental Protection. 2008. Florida Green Industries best management practices for protection of water resources in Florida. Florida Dep. Envir. Protection. http://www.dep.state.fl.us/water/nonpoint/pubs.htm

Florida Department of Environmental Protection. 2009. Florida-friendly landscape guidance models for ordinances, covenants, and restrictions. FDEP and the University of Florida. http://www.dep.state.fl.us/water/nonpoint/pubs.htm

Florida Department of Agriculture and Consumer Services. 2007. Rule 5E-1.003(2). Labeling requirement for urban turf fertilizers. http://www.flaes.org/pdf/Urbun_Turf_Fertilizers_Rule.pdf

Florida Department of Agriculture and Consumer Services. (2009). Archive fertilizer tonnage data. http://www.flaes.org/complimonitoring/past_fertilizer_reports.html

Haley, M.B., M.D. Dukes, G.L. Miller. 2007. Residential irrigation water use in Central Florida. Journal of Irrigation and Drainage Engineering 133(5):427-434.

Hartman, Richard, Fred Alcock, and Chris Pettit. 2008. The spread of fertilizer ordinances in Florida. Sea Grant Law and Policy Jour. 1(1): 98-114. http://www.olemiss.edu/orgs/SGLC/National/SGLPJ/Vol1No1/5Hartman.pdf

Heisler, J., P. M. Glibert, J. M. Burkholder, D. M. Anderson, W. Cochlan, W. C. Dennison, Q. Dortch, C. F. Gobler, C. A. Heil, E. Humphries, a. Lewitus, R. Magnien, H. Marshall, K. Sellner, D. Stockwell, D. K. Stoecher, and M. Suddleson. 2008. Eutrification and harmful algal blooms: A scientific consensus. Harmful Algae. Doi:10.1016/j.hal2008.08.006.

McCready, M.S., M.D. Dukes, and G.L. Miller. 2009 (in review). Water conservation potential of smart irrigation controllers on St. Augustinegrass. Agricultural Water Management.

Sarasota County, Florida, Ordinance 2007-062 (August 27, 2007).

Sartain, J. B. 2007. General recommendations for fertilization of turfgrasses on Florida soils. Fla. Coop. Ext. Publication #SL21. http://edis.ifas.ufl.edu/LH014.

Sartain, J.B. 2008. Comparative influence of N source on leaching of N and St. Augustine quality, growth and N uptake. Soil and Crop Sci. Soc. Florida Proc. 68: (In press).

Sartain, J.B., L.T. Trenholm, E.F. Gilman, T.A. Obreza, and G. Toor. 2009. Frequently Asked Questions about Landscape Fertilization for Florida-Friendly Landscaping Ordinances. Fla. Coop. Ext. Publication #ENH1115. http://edis.ifas.ufl.edu/WQ143.

Skogley, C.K. and C.D. Sawyer. 1992. Field research. In D.V. Waddington (ed.) Turfgrass. Agronomy 32:589-614.

Snyder, G. H, B. J. Augustin, and J.M. Davidson. 1984. Moisture sensor-controlled irrigation for reducing N leaching in bermudagrass turf. Agron. J. 76:964-969.

St. Johns County, Florida, Ordinance 2003-52 (May 27, 2003).

Tampa Bay Estuary Program. 2008. Final report from the workgroup to develop residential fertilizer use guidelines for the Tampa Bay Region. http://www.tbeptech.org/Fertilizer/Res%20Fertilizer%20final%20report-August%2014_%202008.pdf

Trenholm, L. 2007. Homeowner best management practices for the home lawn. Fla. Coop. Ext. Serv. http://edis.ifas.ufl.edu/EP236.

Trenholm, L., E. Momol, and T. Nell. 2009. Frequently Asked Questions about Florida-Friendly Landscaping. Fla. Coop. Ext. Publication #ENH1113. http://edis.ifas.ufl.edu/WQ144.

USEPA. 1999. Preliminary data summary of urban storm water BMPs http://www.epa.gov/waterscience/guide/stormwater/

Village of Wellington, Florida, Municipal Code 30-155.

Tables

The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other extension publications, contact your county Cooperative Extension service.

U.S. Department of Agriculture, Cooperative Extension Service, University of Florida, IFAS, Florida A. & M. University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Millie Ferrer-Chancy, Interim Dean.

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