Chapter 4 Activities
4. Fertilizer Management & Soil Regeneration
Introduction
Although farmers have used manure to fertilize crops for 8,000 years, widespread use of industrially produced synthetic fertilizer began in the 1960s, dramatically altering the natural nitrogen cycle by increasing the amount of bioavailable nitrogen in soils and water. Today, production and use of synthetic fertilizer fuel agricultural productivity that feeds nearly half the global population (Erisman et al., 2008) and maintains extensive urban turfgrass lawns and ornamental landscaping. Between 2013 and 2020, nitrogen fertilizer products distributed to the Sarasota County region ranged from 34 to 324 tons per year. These products are dominated by synthetic mixes of inorganic nitrogen, phosphorus, and potassium (N-P-K) and are primarily used on farms, golf courses, athletic fields, and lawns (FDACS 2020) (see Chapter 4.2).
Inorganic slow-release formulas use polymer coatings to slow nutrient release, increasing plant uptake efficiency and reducing runoff. Some fertilizer products are nitrogen- and phosphorus-free, supplying micronutrients or soil amendments like iron. Organic fertilizers—such as manure, compost, or animal byproducts—gradually release nutrients, do not rely on fossil fuels for production, and help build soil structure and health. The use of organic fertilizers promotes long-term soil productivity and carbon sequestration (see Chapter 4.6). Landscapes utilizing Florida-native plants, adapted to local soil and weather conditions, require less fertilizer, pesticides, and irrigation, and can be attractive alternatives to turfgrass and non-native ornamentals.
Nutrients from fertilizer can leach from soils or be washed off landscapes during storms and transported to water bodies. This is exacerbated when fertilizer is overapplied, applied improperly before rain, or applied adjacent to waterways. Excess nitrogen and phosphorus can fuel algal blooms, degrade water quality, harm aquatic life, and threaten public health. In areas where reclaimed water is used for irrigation, fertilizer impacts are compounded because reclaimed water often contains high nitrogen levels (see Chapter 1.2). Sarasota County soils are naturally rich in phosphorus, meaning local primary productivity is more sensitive to nitrogen inputs.
Activity 1:
Estimate Nutrient Loading From Fertilizer
Understanding the relative contribution of fertilizer to nutrient loading can help prioritize management strategies. Loads may be reasonably estimated using nutrient budget coefficients based on inputs, plant uptake, and outflows for different land uses.
Activity 2:
Reinstate FDACS Public Reporting on Fertilizer Distribution
Publicly accessible data on the distribution and sale of fertilizer by category and by county is urgently needed to accurately estimate nutrient loading from fertilizer, assess compliance with fertilizer regulations, and track the success of educational efforts.
Activity 3:
Strengthen Local Fertilizer Ordinances and Improve Compliance
Sarasota County was among the first in the state to enact local restrictions on fertilizer use to protect water quality. The ordinance could be substantially strengthened by requiring point-of-sale educational signage to promote greater awareness and compliance.
Activity 4:
Deliver Targeted Education and Resources to HOAs
Lawn care standards imposed in deed-restricted communities can contribute to excess fertilizer use and water pollution. Educating Homeowner Associations about Florida-Friendly Landscaping™ practices is an efficient way to maximize environmental benefits with limited educational resources.
Activity 5:
Deliver Targeted Education and Resources to Landscape Professionals and Golf Course Managers
Sarasota County has almost 6,000 acres of golf courses and athletic fields and a large number of professionally managed residential and commercial lawns and landscapes. Although training in Best Management Practices is required for golf course managers, athletic field managers, and lawn care professionals, compliance is not monitored. Improved outreach is needed to encourage fertilizer BMP adoption and assess nutrient reduction.
Activity 6:
Deliver Targeted Education and Resources to Farmers and Ranchers
Sarasota County has a strong agricultural heritage founded on cattle ranching and now diversified into multiple commodities, including citrus, sod and ornamental plant nurseries. About 46% of Sarasota County’s registered and eligible farms voluntarily participate in agricultural Best Management Practices to reduce nutrient runoff and better manage water use. Additional incentives are needed to encourage more farms, including small crop, animal farms and hobbyists, to embrace sustainable practices.
Activity 7:
Encourage and Facilitate Commercial Composting and Redistribution for Rebuilding Soils
State law mandates that Sarasota and other large counties recycle 75% of their waste stream. Composting of yard waste contributes to that goal, but food waste is not collected or composted at large-scale. Conflicting interpretations of food waste management within county codes should be resolved to facilitate recovery and recycling of organic waste as a source of clean energy, an alternative to synthetic fertilizers, and a small-business opportunity.
