Water Quality Improves After Lawn Fertilizer Ban, Study Shows

[The Straight Story]

Water Quality Improves After Lawn Fertilizer Ban, Study Shows

ScienceDaily (Aug. 17, 2009) — In an effort to keep lakes and streams clean, municipalities around the country are banning or restricting the use of phosphorus-containing lawn fertilizers, which can kill fish and cause smelly algae blooms and other problems when the phosphorus washes out of the soil and into waterways.

But do the ordinances really help reduce phosphorus pollution? That's been an open question until now, says John Lehman, professor of ecology and evolutionary biology at the University of Michigan.

"It's one of those things where political organizations take the action because they believe it's the environmentally conscious thing to do, but there's been no evidence offered in peer-reviewed literature that these ordinances actually have a salutary effect," Lehman said.

Now, such evidence exists in a study published by Lehman and students Douglas Bell and Kahli McDonald in the journal Lake and Reservoir Management. The paper, published online Aug. 14, shows that phosphorus levels in the Huron River dropped an average of 28 percent after Ann Arbor adopted an ordinance in 2006 that curtailed the use of phosphorus on lawns. Phosphorus is naturally plentiful in southeast Michigan soils, so fertilizing established lawns with the nutrient is generally unnecessary.

Lehman was in an ideal position to assess the effectiveness of the Ann Arbor ordinance because he and undergraduate student Julie Ferris were already studying nutrient levels in the Huron River and two downstream lakes, Ford Lakes and Belleville Lake, for a different research project. Ferris used some of the data from that project in her senior honors thesis, and she and Lehman published a paper on the Ford Lake and Belleville Lake research, but they weren't sure what to do with the rest of the data from the Huron River around Ann Arbor.

http://www.sciencedaily.com/releases/2009/08/090817190741.htm

[NYC_SKP]

1. Lawns. You mean those green things that usually are a waste of water and a vanity statement?

Good news that they've studied the effects on groundwater quality.

But... Lawns take a lot of water away from other uses and any use that depletes the aquifer promotes entry of nasty substances, no?

[PDJane]

3. yes.

not to mention the pesticides and herbicides and lawnmowers.......gah. Waste of time and earth.

[Chulanowa]

4. Grass lawns are America's #1 agricultural crop

And also its most completely useless.

[justabob]

5. lawns aren't all bad

I understand what you are saying about lawns, water use, vanity, Chemlawn (whatever their name is now) and lawnmowers and all the rest of it, but I have another take on it because of something I have noticed in my neighborhood in recent years. Developers have come in and plowed over smaller homes with decent, but not extravagant yards, and replaced them with homes twice the size and no lawn at all, or very minimal green space plus massive apartment complexes and lots of cement etc. As development increased the water from rainstorms had nowhere to go... streets are flooded if we get a good downpour. It doesn't ever last long but it is a problem. We do have storm drains that feed into our reservoirs, but these have not kept up with the real estate development in the area, and the storm sewers spout fountains out of the manhole covers when we get a good storm. (the city is working on it, but the storm sewers are not adequate)...So the water is getting to the reservoirs but only after going down the streets and picking up oil trash and whatever else. I would rather that water go through peoples' yards and into the groundwater that way than down the street, down the sewer and into the area lakes. I have no source to link to or study to cite, just my observations living in the same spot for a decade, so this is just IMHO.

and on edit.... I am not advocating fertilizers or chemicals in anyway, just advocating green space (even if very small) in the heart of a fairly large city.

[Statistical]

6. Exactly lawns like any green space is not all bad.

They remove CO from the air and produce oxygen (due to their high respiration rate a lawn per sq foot removes about 3x the CO2 as a large tree).
They reduce temperature of surrounding area by releasing water vapor during hottest part of the day (reduced city heat island effect) which reduces air conditioning costs (and associated pollution).
They act as a macroscopic filter, rather than water flowing down streets and dumping all kinds of solids into water supply which requires costly filter they do it naturally.
They provide a heat shield that prevents sun from sterilizing soil, micro organisms, and other lifeforms survive under the lawn canopy.
They prevent erosion by holding soil in place.


A major problem is lack of education.

Homeowners generally speaking:
* over fertilize the lawn.
* fertilize at the wrong time. should plan for a dry period to avoid washout.
* don't add enough organic material (top soil, peatmoss, compost) so they are trying to grow a lawn on pure clay which is very resource intensive (water, fertilizer, poisons).
* not get their soil tested (done for free by local co-op) correcting for PH can reduce water, poison, and fertilizer needs.
* water incorrectly (should be a few deep watering to promote deep roots rather than a lot of surface watering)
* don't have a rain sensor to stop watering on weeks w/ 1"+
* due to all of the above create an ecosystem which is weed friendly and lawn hostile then compensate by using tons and tons of poison to try and kill the weeds and promote the grass.

A properly cared for lawn requires less water, fertilizer, and poison. My lawn tends to strangle out weeds naturally without poison. The thick lawn makes it difficult for weeds to get startd and the deep but frequent watering means the weeds never develop the roots necessary to survive the summer heat. I only need pre-emergent crass grass preventer in the spring. Crabgrass is easier prevented than killed.

[NYC_SKP]

7. I know what you mean about lot coverage and green spaces.

Typical developments here in California have tended toward huge homes on normal lots with five feet between them and tiny front and back yards.

Options to lawn include different designs using native plants and/or less water intensive plants.

:thumbsup:

[justabob]

8. yes, I see

I read your post and wasn't thinking lawn = grass, but that lawn = yard - that space between the front door and the street, and couldn't imagine what the problem was, but I see now I was suffering vocabulary failure. Sorry about that. :)

Yes, native plants and other good options are out there, and thankfully, more and more people are going that route. I do wish the developers and/or the city would think about things like rain water management/conservation, street flooding etc when they issue building permits. Having a major six lane artery flood whenever we get a good rain may help that.... maybe. The city has been educating people about watering the grass too, so there is some progress. Sadly, it has taken several years of drought and water rationing to get here though.

[PDJane]

2. Not much of a surprise..........

And we are going to run out of Phosphorus soon, since we've been dumping it in lakes instead of ensuring that it's recycled.