What You Can Do To Stop Algae Blooms From Contaminating Our Water.

Maryam Ayoubi

Recently, Toledo, Ohio residents went through two days of a natural disaster: Lake Erie, their water source, was contaminated by vile green slime. It was a nightmare.

The culprit is toxic algae blooms fed primarily from agricultural runoff from synthetic phosphorus fertilizers farmers apply. Another less publicized contributor is synthetic phosphorus used on residential turf. Chances are you don’t own a corn or soybean farm; However, if you have a lawn or garden and are using synthetic fertilizers, you may be contributing to the proliferation of algae blooms in our water supply. 

Phosphorus, the middle number listed in the N-P-K (Nitrogen - Phosphorus – Potassium) on the back of commercial fertilizer packages, is a critical nutrient for plant growth. However, it is also a major source of pollution. Indeed, the residential use of lawn fertilizers containing synthetic phosphorus is responsible for a significant amount of pollution of lakes, rivers and ground water. While many in turf management say natu­ral sources of soil nutrients reduce hazard­ous runoff, the chemical industry claims that the source of phosphorus in a fertilizer is irrel­evant, and phosphorus bans should apply to both synthetic and organic sources. However, the solution is often found not solely in a product replacement, but in the overall management system that protects and nurtures the soil.

Phosphorus is an “immobile” nutrient and is retained in the soil. Consequently, soil erosion and over-ap­plication of phosphorus result in a significant amount of phosphorus pollution. Preventing soil erosion and performing soil tests is crucial. The source of a fertil­izer is relevant.  While or­ganic production methods build a lawn’s capacity to hold soil, synthetic systems weaken this abil­ity. Applying synthetic fertilizers to a lawn pumps nutri­ents into the soil faster than the turf can absorb them, resulting in much of the groundwater leaching runoff detrimental to water sources. Excessive applications also cause microbes in the soil to go into a feeding frenzy, devouring all the available carbon material they can find. Continu­ous applications of these synthetic fertilizers exhaust soil life, leading to bare and sterile land. 

Conversely, organic land management yields the optimum environmental safeguards and nurtures healthy turf. The goal of an organic turf program is to feed the soil by using methods that build organic matter and encourage beneficial microbial diversity. This is achieved through cultural practices such as mowing, aeration, proper watering, and over-seeding without the use of chemical fertilizers, insecticides, herbicides, or ungicides. Only fertilizers or soil amendments approved by the Organic Materials Review Institute (OMRI) are guaranteed to comply with the rigorous standards of the Organic Foods Production Act (OFPA). Building organic matter with compost and other organic nutrients insures natural phosphorus is available to the plant. Beneficial microbes slowly break down organic fertilizer and provide turf and plants with nutrients throughout the growing season. Moreover, Gentle in­creases in the soil’s fertility enhance its ability to store nutrients, resulting in decreased runoff. Thus, Organic fertilizers create lush verdant lawns and gardens that require less overall maintenance and also help protect our drinking water. 

How to Maintain a Sustainable Organic Lawn, 

Develop healthy soil. Sample the soil with a “soil probe” – cut or dig a small hole about 10” deep.  The lawn should have between 5”-6” of topsoil, which is the darkest soil layer. If needed, add topdressings of organic matter, such as compost to the topsoil. Avoid “natural” and “organic” products with the following compo­nents: biosolids (sewage sludge), synthetic chemical wetting agents or products with inert ingredients. Avoid any products that don’t list all of their ingredients. Unlike the USDA organic symbol that can be found on food, “organic” and “natural” claims on packaged lawn care fertil­izers are not subject to the requirements of OFPA. These labels can be misleading because laws do not regulate these claims.

Test your soil. Adjust the pH if necessary. Low pH means high acid content – add lime to raise the pH. High pH means high alkaline – add sulphur to lower the pH (take care not to burn the lawn). Watch for hints of pH imbalance such as a dandelion infestation which love a 7.5pH (grasses prefer a pH of 6.7 - 7.0). 

Choose suitable grass seeds. You can find out which grass is most suitable to your climate from your local cooperative extension. Also,  Overseeding your established lawn can reduce weed problems. 

Aerate the lawn twice a year. Soil compaction is one of the largest causes of weed problems. Aerating, allows air, water, and nutrients to reach the roots of the grass. 

De-thatch. Thatch is a dense layer of grass stems and roots on the surface of the soil. When thatch layers become ½” or more grass roots become shallow and susceptible to insects, disease, and weather stress. Thatch is reduced by aeration and topdressing with organic matter.

Fertilize. Use a slow release fertilizer formulation once a year, usually in the fall, to increase the efficiency of nutrient uptake and reduce nutrient runoff and leaching. Fast-release fertilizers can induce pest outbreaks. Avoid synthetic chemical nitrogen-rich fertilizers that can kill valuable microorganisms in the soil. Determine your lawn's nutrient needs by a soil test. 

Water properly. Over or under watering can induce pest outbreaks. Water should wet the soil to the depth of the grass root zone and be nearly dry before watered again. Avoid frequent, shallow waterings, which promote shallow root systems. Natural, organic fertilizers can increase the water-holding capacity of the soil. 

Mow correctly. Mow with sharp blades set to 3”. Never cut more than 1/3 of the grass blades in a single mowing and leave a light layer of grass clippings on the grass.  Mow frequently enough to ensure that weeds are unable to establish well. Weeds can also be pulled by hand. If you feel that an herbicide is necessary, use natural corn gluten or a fatty-acid soap.

Insects. Your control strategy will depend on your particular pest problem. You can control grubs by applying milky spore disease bacterium. Kill chinch bugs by drenching the thatch layer with an insecticidal soap. Sod webworms can be controlled by de-thatching and applying Bacillus thuringiensis (Bt) when larvae are present, applying nematode parasites, or with insecticidal soap. 

Disease. Disease problems are often the result of improper nutrient or moisture conditions. The key to preventing lawn disease is to use locally adapted, resistant varieties of grass. 

For more information please visit : www.beyondpesticidesohio.org

To contact Maryam Ayoubi: mayoubi125@hotmail.com

---