C C E N T R A L U Preventing pesticide 1 contamination of water sources 2 By Parker Platts and Stephen H. Futch ater is a vital and between soil particles, gravel and rock. precious resource to Groundwater, the source of water for our environment. wells and springs, is where approximately Protecting Florida’s 90 percent of Florida’s drinking W 3 water sources should be a high priority water comes from. Groundwater when dealing with pesticides. The must be protected from pesticide 1: To help determine when to apply restoration of pesticide-contaminated contamination, as the restoration of pesticides, applicators should check water is complex and expensive, and in underground water pollution is very the weather forecast periodically many cases, not feasible. The pesticide difficult if not impossible. during the day. user must be diligent in employing good Leaching is the downward 2: Follow the instructions on the management practices that prevent movement of pesticides or other pesticide label for proper storage pesticides from polluting our waters. compounds in water through the soil and disposal. Surface water is the water on top of profile, which can cause pollution of 3: Keep pesticides in a locked storage the earth’s surface such as lakes, rivers, the groundwater. The physical and facility. canals and irrigation ditches. More chemical characteristics of a pesticide, than a third of the state’s fresh water as well as the properties of the soil, in its original form for an extended withdrawals comes from surface water. influence the ability for leaching. period before breaking down. A Pesticides can move downslope in Characteristics of a pesticide that pesticide that is quickly broken down is runoff water or with eroded sediment affect its ability to leach are adsorption, less prone to pollute the groundwater. to contaminate surface water. solubility and persistence. When leaching is a concern, look for Runoff is the water that flows Adsorption is the ability of a label information or call the pesticide downslope over the land during pesticide to bind with soil particles. If a manufacturer and ask about these heavy or continual rainfall. This pesticide is held strongly on the surface pesticide characteristics. runoff water can carry pesticides of soil particles, it is less likely to leach. Soil properties are also an with it to unintended surface-water Solubility is a measure of the important factor in the movement and bodies. Factors affecting runoff are ability of a pesticide to be dissolved breakdown of pesticides. These factors rainfall amounts and intensities, in a solvent or water. A more soluble include permeability, organic matter slope, vegetative cover, temperature substance will move more easily in and depth of groundwater. and soil type. water through the soil. Soil permeability refers to how Groundwater is the water beneath Persistence is the ability of a easily or quickly a liquid will flow the earth’s surface, found in the spaces pesticide to remain present and active through the soil. Basically, the larger 16 Citrus Industry May 2015 the particles that make up the soil, the more permeable it is. A coarse sand is more permeable and porous than Available Now: fine sand or clay, and therefore more Ruby Red/Sour 7,000 prone to leaching. Hamlin/Sour 1,500 Valencia/Sour 1,500 Organic matter content has a Eric Nething (813) 477-4023 Robles/Sour 500 large impact on the water-holding [email protected] capacity and pesticide adsorption of Sunburst/Sour 500 Hamlin/Carrizo 500 the soil. Organic matter consists of Doug Holmberg (813) 335-8800 [email protected] Valencia/Carrizo 5,000 decomposed plant and animal material Navel/Carrizo 1,000 in the soil. Soils that are high in Lee/Carrizo 500 organic matter hold more water in the Rootstocks Hamlin/SWG 8,000 rooting zone, which results in a lower Available: Valencia/SWG 15,000 leaching potential. Sour orange x639 Red Navel/SWG 1,000 The depth of the groundwater has Honey Bell/SWG 1,000 Swingle us802 Ruby Red/F83 1,000 an effect on leaching as well. An area Carrizo us812 Honey Bell/F83 500 with a shallow water table and no shal- Cleo us897, us942 low restrictive hardpan has a higher chance of pesticides reaching the groundwater than an area with a deep 13430 Hobson Simmons Rd., Lithia, FL 33547 water table. Such a table has more ver- tical soil area, which is more favorable to pesticide adsorption and degrada- tion as it moves through the soil. The following management practices should be incorporated into every pesticide program to help Blue Goose has the people, prevent ground and surface-water contamination. experience and resources to improve your return on your investment EVALUATE THE SITE Now that you know how pesticides Growers Cutting Heavy equipment can move into water sources, you can • Installation services • Services for Agricultural and • Grove care evaluate the site as to its vulnerability • Hedging Commercial construction • Crop manage- • Excavation • Grading • Land clearing to pesticide contamination. The slope ment • Topping • Waterway maintenance – Water • Property • Skirting of the field in relation to lakes, ponds, control structure installation streams, canals and wetlands should management • Cross Hedging be assessed. If you find water bodies FORT PIERCE that are vulnerable, berms or banks 772-461-3020 Main Office Real estate between the surface-water bodies and 9901 Okeechobee Rd. 34945 • Leasing Services the application sites will reduce the ARCADIA CLEWISTON • Agricultural sales and purchases 863-993-9661 863-677-1125 chance of pollution from runoff. Also, 6057 Nichols St. 34266 2550 Witt Rd.. 33440 buffer zones such as grass borders can help in filtering between the application site and water bodies. The soil properties should also be evaluated for leaching potential, considering the texture, structure and organic matter content. Some pesticides may have restrictions on where they can be applied according to the soil properties. Always read the label carefully and follow label directions. A good resource to determine the soil characteristics is the Natural Resources Conservation Service Web Soil Survey website Citrus Industry May 2015 17 (http://websoilsurvey.sc.egov.usda. USE INTEGRATED PEST PROPERLY CALCULATE, gov/App/HomePage.htm). If you MANAGEMENT CALIBRATE AND APPLY have a highly leachable soil, take extra Integrated pest management The key to an effective pest control precautions in preventing pesticide soil (IPM) is a comprehensive strategy program is to efficiently keep the exposure and, when possible, choose of pest control. The major objective pesticide on the target site in the pesticides that are less likely to leach. is to achieve desired levels of pest proper amount. Labeled rates should control in an environmentally never be exceeded. To help eliminate MONITOR THE WEATHER responsible manner, combining having to dispose of leftover spray AND IRRIGATION physical, chemical, cultural and mix, carefully calculate the amount Intense downpours or prolonged biological control methods. IPM of pesticide needed to treat the site. periods of rain affect runoff and combines understanding the causes Pesticide application equipment erosion rates to a large degree. Florida of pest outbreaks, manipulating the should be calibrated frequently to receives more than half of its annual crop ecosystem for pest control and assure the pesticide rates are being rainfall from June through September, monitoring pest populations and their applied within the desired application so extra care should be taken when life cycles to determine if and when levels. Sprayer equipment should applying pesticides during these wet the use of pesticides is necessary. be checked often for leaks and months. To help determine when to When pest monitoring malfunctions. Accurate calibration make pesticide applications, applicators shows pest levels have reached and properly working equipment will should check the weather forecast the threshold where pesticide help prevent pesticide contamination periodically during the day. If heavy application is necessary, choose of surface water and groundwater. downpours are predicted, pesticide pesticides with the least possible applications should be delayed until hazard to people and the USE EXTRA CARE WHILE favorable weather returns. Irrigation environment, and apply the lowest MIXING AND LOADING scheduling should be carefully rate required for adequate control. Mixing and loading require extra managed, taking into consideration Reducing the amount of pesticides care. The people who perform these when pesticide applications are made to applied lowers the risk of water tasks need to be attentive, responsible minimize runoff and leaching. pollution and the grower’s costs. and properly trained. When mixing and loading, the pesticide is in a concentrated form and is more toxic than when it is diluted in the application tank. Precautions should be taken to prevent spills and We keep you growing... overfilling that could cause water contamination. In many instances, mixing and loading is performed at the same locations on the farm, due to the location of water required for mixing. • Over thirty years of industry experience Repeated spills over months or years at the same location may exceed the soil’s capabilities to degrade • Florida’s largest citrus crop insurance provider or adsorb the pesticide, increasing the chances it will leach into the • Knowledgeable & professional service groundwater. Permanent or portable containment pads can be used to • Products for all your risk management needs avoid point-source pollution of groundwater such as that caused by pesticide soil saturation. If containment pads are not used, Carden & Associates, Inc. mixing and loading should be rotated 888.296.7533 toll free between many locations to reduce the [email protected] chances of pesticide buildup in the www.cardeninsurance.com soil. When choosing mix-and-load sites, check the soil for characteristics that are not conducive to leaching and carden runoff, and avoid mixing and loading within 300 feet of a well.