By Christopher Murray, PhD
Research consistently shows the volume of runoff decreases when turf is fertilized. Second, most studies show the concentration of nutrients in the runoff is more or less proportional to the amount of fertilizer added.
When considering the total amount of nutrients, though, the effect on runoff volume wins out over concentration: fertilizing decreases the total amount of nutrients in runoff, in most cases, compared with lawns where fertilization is eliminated. While the concentration of nutrients in the runoff may be higher when runoff occurs (and there are many studies showing that even nutrient concentration can be equal or lower with fertilization), because runoff occurs less frequently, the overall effect is often to reduce the amount of nutrients leaving the lawn.
Total nutrient loss is not the only item of concern when considering water quality. It is important to note even clean water can be a pollutant, as it carries with it the potential for erosion downstream and can overload stormwater systems, which can sometimes spill into sewer systems and cause hazardous overflows. Very little attention is paid to the benefit turfgrass provides simply because of its ability to decrease the strain on stormwater management systems.
Read the full article: Turf Fertilization: Decreasing contamination of runoff