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Urban Water Qualitv and Fertilizer Ordinances:Avoiding Unintended Consequences:A Review.... 15 20 c W � 15 E A � � c ja t 10- r d Q R .10 5 c as v CL o Qo a 0 .o � cpG �Q � oo `te `� Is1V CF Figure 5.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 data sets analyzed contained between 28 and 64 complete years of data(Harper and Baker,2007). over-irrigation showing that some homeowners evapotranspiration(ET)+rainfall resulted in loss of greatly exceeded irrigation requirements. 50%of the applied soluble N(Snyder et al., 1984). Proper irrigation management is critical to preventing Any attempt to minimize N and P pollution from nutrient losses. the urban landscape will be for naught if irrigation management practices are not included in fertilizer New technology is available in the irrigation guidelines.Barton and Colmer(2004)reviewed the arena known as"Smart Irrigation." New controllers literature regarding irrigation and N management. typically monitor soil moisture status and void or These authors concluded that N losses are low(<5% permit irrigation based on soil moisture levels.These of applied N)from any established turfgrass when irrigation controllers use inputs of information irrigation is not excessive,and with moderate(not (sensors)from the irrigated area to determine or excessive)rates of N fertilizers.Irrigation scheduling regulate irrigation.Research in Florida on soil that does not result in water moving below the root moisture sensor controllers has shown that irrigation zone helps keep N in the root zone minimizing N savings can exceed 70%of automatic, losses. Sometimes this approach even resulted in clock-scheduled irrigations with a variety of improved turfgrass growth and quality. controllers under normal rainfall conditions (Cardenas-Lailhacar et al.,2008;McCready et al., In an early benchmark study in Florida by 2009).Savings during dry periods were less dramatic Snyder et al.(1984)on irrigation management and N but were as much as 30 to 40%(McCready et al., leaching,scheduling irrigation was done by a 2009).Finally,evapo-transpiration controllers have moisture sensor device that canceled irrigation when also been shown to result in savings of 43%during the soil contained adequate moisture.Controlled dry conditions(Davis et al.,2009).It should be noted irrigation led to more efficient irrigation and to that scheduling irrigation with soil sensors may not be negligible loss of the soluble N applied(ammonium consistent with current rules on irrigation of Florida nitrate)(Snyder et al., 1984).Irrigation at 125%of landscapes.The reader is referred to the local water