A representative from the Metropolitan Water Reclamation District of Greater Chicago gave another interesting statistic that 42% of Cook County is covered by an impervious surface. This means that we are approaching half of the land area is covered by a material that does not soak in water during rain event. Roads, parking lots, and buildings are the norm in this county but how can we expect to move that water to the right location when almost half of the soil can’t absorb it? My question is, do we blame flooding on global warming or the reduced ability of our region to absorb the rainfall?
Nutrient levels in bodies of water are also a concern. Phosphorus is the
nutrient being watched closely. Several states have passed or considered (Illinois included) banning phosphorus fertilizer application to turfgrass in order to reduce the chances of leaching and runoff. Many people and legislators believe that reducing the applications of this nutrient will reduce the amount of phosphorus that ends up in our lakes. These calls to ban the nutrient for applications are sure to be tough and the strategy for some may be to just adapt (see picture below). However, it is always good to know the science behind phosphorus. One speaker, Dr. Doug Soldat, from University of Wisconsin has studied just that.
I remember one of my essay questions in soil fertility class was directed towards phosphorus movement. Phosphorus has a strong affinity to attach to the soil which prevents leaching, so how does it end up in our water? Dr. Soldat had four key points to make during his presentation, the first addressing my essay question as a student.
1) Sediment (from erosion) is the primary source of phosphorus loss.
2) Most phosphorus lost from turfgrass is during winter.
3) Improving soil quality is the most effective way to reduce nutrient export and irrigation use.
4) Dense groundcover (healthy turfgrass) is good for the urban environment.
Dr. Soldat’s interesting statistic showed the amount of sediment lost from construction sites far surpassed all other sources combined. In order to reduce the amount of phosphorus entering our lakes we should address the big inputs and our efforts on the smaller inputs like turf will only result in minor changes. Dr. Soldat’s forecast is that phosphorus levels in our lakes will decline in the short term. Why? Well can we blame the economy? Hmm, has the amount of construction
declined lately?
As turf managers we will always be asked to minimize our nutrient losses either through our voluntary actions or mandatory. Here are a few actions that I gathered from all the presentations to preserve water quality and quantity.
1) Apply organic fertilizers at rates of recommended phosphorus and not nitrogen (which usually results in over applying phosphorus).
2) Sweeping sidewalks, parking lots, and other impervious surfaces clean of plant debris and fertilizer applications.
3) Best management practices that we have all heard like mow higher, return clippings, reduce watering, and water at correct times.
4) Treat excess water from rainfall as an asset instead of putting it in detention.
We may have heard those points many times but we still see people watering before a rainstorm. Education of our neighbors and friends will beimportant!
Keith Rincker
KRincker@cdga.org
Chicago District Golf Association
11855 Archer Avenue
Lemont, IL 60439
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