View Full Version : NPK and lime recommendations for football field
04-30-2008, 05:17 PM
I am a project manager on a site that is installing a football field for a middle school in Tacoma, Wa. My landscaper had the soil tested per the specifications (see attached), but the testing lab would not recommend a gypsum rate, lime rate and NPK rates and amounts, which are also required by the specs. Does anyone know of any turf consultants in the Pacific NW that would look at this soil test and recommend rates for amendments and fertilizers to correct any deficiencies therein for growing turf?
We are coming down to the wire in the next day or two, so if you have any suggestions, they would be greatly appreciated. Thank you.
05-01-2008, 08:32 AM
Contact a county extension agent or if WA has a land grant university they should be able to help.
05-01-2008, 09:42 AM
Rtom45 is absolutely right.
Another thing though...is that soil samples, in-and-of themselves generally never disclose things like NPK 'recommendations' !
If you disclose the grass species when you send in the sample(s), they'll print out an "automatic" NPK recommendation, usually based upon the nearest reputable university's testing in their lawn field plots, and / or a professor guru.
NPK and micro nutrients are something that's determined by the grass species type(s), the level of usage and "wear and tear" in athletics, as well as the CLIMATE the grass is growing in....and this is where a county extension agent, or a knowledgeable (and somewhat unbias and honest :rolleyes:) vendor in the fertilizer & seed arena can maybe help you.
The test shows a recommendation for reducing the very high magnesium levels; with a very SPECIFIC calcium recommendation and rate with the gypsum app(s).
Generally...if something isn't "broke", don't fix it!
This test makes no mention of lime whatsoever...and the pH falls well within a range of what (I think) most pros in your area would consider pretty much ....."IDEAL".
( I sure wish we had a pH of 6.5 here in "limestone country"...in southern Ohio !!! :laugh:)
But again...consult a professional in your area.
Unfortunately, in many people's minds around the country, the need to apply lime has over time become one of those 'placebo effect' things that should be done to their lawn / garden... and "because SOMEONE told me to... is usually a good enough reason anymore.
05-01-2008, 10:00 AM
Oops...:cry:..meant to say just simply "nitrogen", instead of "NPK" in the opening couple lines of that last blog !
05-03-2008, 12:40 PM
Don't get too caught up with gypsum. Gypsum is calcium sulfate, it is usually used on sodic soils that have a higher pH and high salts. Putting gypsum on these soils floods the soil system with calcium that knocks sodium off the cation exchange without affecting the soil pH. Calcium also helps with soil structure. I would assume you are not dealing with sodic soils. Therefore I wouldn't worry about gypsum. Typically, if your soil pH is adequate your calcium levels are as well, Sandy soils and sand based putting greens are an exception.
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