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  #21  
Old 04-29-2013, 10:13 PM
greendoctor greendoctor is online now
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Throwing KCl on centipede has caused me problems. It is related to type of soil and the existing chloride levels in that soil. I take what UH says about turfgrass with a grain of salt. Most of what is said is not research work. It is advice directed towards non professionals. There has not been a Turf Scientist at UH since Charles Murdoch. Jim Brosnan was here for about a year, then he left to UT. The closest thing to a Turf Scientist is the senior Weed Scientist.

What I do know is to be very mindful of what I apply to soils that are not only salt contaminated but hard to leach. I have also seen results contrary to what "universities" have been telling people about centipede fertilization once attention is paid to the source of N and K. No adverse effects have occurred on lawns fed 4-6 lb of N and an equal amount of K. No urea is used. All of the N is ammonium based except for the nitrates in potassium nitrate. What I consider a bad application on any variety of turf, not just centipede is one that forces a lot of soft surge growth.
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  #22  
Old 04-30-2013, 12:08 AM
Skipster Skipster is online now
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If you're seeing Cl toxicity, you must be in the super arid desert portion of Hawaii. Cl isn't even in a problem in the mainland desert, where rainfall of less than 2 in/yr are common. If you think you are overloading on Cl, it is likely a leaching problem, where you have heavy soils and very little rainfall (<2 in/yr). In which case, this wouldn't be isolated to only centipedegrass, but prevalent on all turf species.

BTW, I know Chuck Murdoch very well -- he served on my committee for my MS degree. Chuck was great scientist. I've also known Jim Brosnan since his MS days at UMass. I wish I could say he was a scientist. Win some, lose some.

You puzzle me with your "no urea is used. All N is ammonium based ...." Urea converts to ammonium and CO2 very quickly after dissolution in water (hydrolysis reactions). You'll get more ammonium from urea than from any other fert app.

BTW, since your name is greendoctor, are we to assume you hold a doctoral degree? What did you study, and with whom? I would love to know you background.
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  #23  
Old 04-30-2013, 01:03 AM
greendoctor greendoctor is online now
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As I have said before, soils here are in bad shape long before the incorrect materials are applied. A common construction practice is to build entire neighborhoods on top of a coral base. There is up to 12" of red clay put on top of it as "topsoil". What the coral does is contaminate the clay with salt and alkalinity. That clay is hard to leach. Chloride and salt toxicity happens even in areas getting 1+ inches of water from irrigation per week. Some of the salt and alkalinity are from the tap water used to irrigate. The coral base adds more and in windy weather there is no escaping the fine fog of salt from the Pacific Ocean. Inland deserts do not get salt spray 12 month out of the year. Leach the soil properly in a desert and the problem is fixed. Unless the subsoil is pure calcium carbonate and boron carbonate. I have heard of that situation. Grass does turn greener from rain because rain has fewer salts in it. You are right about most grasses having problems with salt. I find that zoysia is also sensitive. Centipede is normally ok because it is grown far inland away from the beaches. But throwing potassium chloride on it is not a good idea. It gets enough from the tap water used to irrigate and it does rain about 30" in those areas so people are not willing to supply the other 20". The soils there are red clay that hang on to everything applied to it. No sand or sandy loam. In many cases, the neighborhood is build on top of a coral fill. So what one would assume to be neutral or acidic and salt free is actually bad.

My preference for ammonium rather than urea stems from observing how the turf responds to each. I also know that most of the lawns I deal with need serious acidification as well. Urea dissociating into NH3 gas and CO2 explains why it does not work the same on soils with a pH of 7+. CO2 reacting with excessive calcium or magnesium forms alkaline carbonates. The NH3 is also here and gone quickly as well. Ammonium sulfate is one of the most acid forming nitrogen sources short of ammonium thiosulfate. On a soil known to be acid, my preferred nitrogen source is calcium nitrate, followed by urea. You see, I do not spread what sold as "turf fertilizer". Sure, I know there is greens grade 46-0-0 and 0-0-62. What I see sold as greens grade preblends locally contains potassium sulfate and is heavy on the ammonium for the reasons I mentioned above. Low cut bermuda has a limit on how much salt it can handle. Especially if it is a dirt fairway or pushup green. Discussions about which preblended granule is better, cheaper, etc are lost on me. I am applying according to the results of a soil test for that site. Therefore, unless it is prilled sulfur, gypsum, or dolomite, all of my nutrients are sprayed, not spread. Solutions are mixed to supply specific rates of N, P, K, S, Mg, Ca and micronutrients.

Not a doctorate. Maybe more like the old barbershop doctor/dentist in the old West. Just an undergraduate in horticulture. Rest of my schooling is from being in the industry for over 20 years or all of my adult life. By the time I was old enough to go to university, Charles Murdoch was long gone and Roy Nishimoto was retiring. That is what I meant by not having any Turf Scientists at UH. Jim was there after my time there was long past. Only person there I can relate to is Joe DeFrank. He teaches the undergraduate weed science class. To this day, we frequently talk about his research, and product trials. In spite of this poor education, I have not done badly for myself. I get grass greener even when bags of over the counter fertilizers or preblends have failed to do the job and some rather stubborn weed problems have been controlled without resorting to digging, tilling, fumigation, or RoundUp.

Which companies are you associated with? Or are you EPA?
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  #24  
Old 04-30-2013, 09:23 PM
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countryclublawnllc countryclublawnllc is offline
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Lesco 15-0-15 or Fertilome 15-0-15 for Centipede?

Muriate of Potash is fine except when applied ai high rates when it is too hot. The relatively small amounts of nutrients we apply will have a hard time affecting the soil under a turf stand. When tilled in at higher amounts to bare soil it is a different story.
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  #25  
Old 05-01-2013, 02:12 AM
greendoctor greendoctor is online now
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Warm season grasses with their longer growing season, proximity to the ocean and need for higher fertilizer rates react differently. If I were to start maintaining cool season grasses, the hardest adjustment for me would be not feeding it like how warm season grasses have to be fed in a frost free climate. I am feeding at least 6 times a year at minimum, it is usually more like 10-12. If only applying fertilizer to an area maybe 2-4 times in a 12 month period, generous allowances can be made for chlorides. Especially in inland areas that do not have background salt contamination. Different grass species have varying levels of salt tolerance as well. Centipede grass stands out as being very intolerant of salt.
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  #26  
Old 05-01-2013, 05:55 AM
Skipster Skipster is online now
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You're story is changing, green"doctor". First, you were claiming that there was something about Cl that caused centipedegrass to perform poorly. Now, you're blaming excess salinity and you've dropped the war against Cl only.

It looks like you've confused Cl and salinity. You can have excessive salinity with or without Cl. Cl by itself is not necessarily a problem.

Check the salt index of the fertilizers you're using. KCl does have a higher salt index than any other K source. But, ther story doesn't stop there. Available fert with urea and KCl has a lower salt index than the same analysis with ammonium sulfate and potassium nitrate.

So, maybe the conversation should have been about the salt index of different fertilizers if you're managing centipedegrass in excessively saline conditions, and not about chlorine. Am I being picky? I suppose so. But, I think that knowing why we do things seperates professionals from amateurs.
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  #27  
Old 05-01-2013, 06:24 AM
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fl-landscapes fl-landscapes is offline
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Dicks like you are the reason good guys like greendoctor leave this site. He has helped a lot of people on here over the years unlike you and a couple other guys who have self esteem issues and constantly try and make yourself feel good by making others feel bad. Don't you have a label to write or something....buzz off azz wipe.


Quote:
Originally Posted by Skipster View Post
You're story is changing, green"doctor". First, you were claiming that there was something about Cl that caused centipedegrass to perform poorly. Now, you're blaming excess salinity and you've dropped the war against Cl only.

It looks like you've confused Cl and salinity. You can have excessive salinity with or without Cl. Cl by itself is not necessarily a problem.

Check the salt index of the fertilizers you're using. KCl does have a higher salt index than any other K source. But, ther story doesn't stop there. Available fert with urea and KCl has a lower salt index than the same analysis with ammonium sulfate and potassium nitrate.

So, maybe the conversation should have been about the salt index of different fertilizers if you're managing centipedegrass in excessively saline conditions, and not about chlorine. Am I being picky? I suppose so. But, I think that knowing why we do things seperates professionals from amateurs.
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  #28  
Old 05-01-2013, 07:05 AM
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Florida Gardener Florida Gardener is online now
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Quote:
Originally Posted by fl-landscapes View Post
Dicks like you are the reason good guys like greendoctor leave this site. He has helped a lot of people on here over the years unlike you and a couple other guys who have self esteem issues and constantly try and make yourself feel good by making others feel bad. Don't you have a label to write or something....buzz off azz wipe.
Yea he's the same guy that was arguing a while back with a bunch of us how some kind of rotary mower does the same job on sports turf as a reel and the funny part was it was getting cut at like 3" or something like that. I guess all the guys in mine and greedocs area who are working on multi million and billion dollar customers properties are just amateurs.
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  #29  
Old 05-01-2013, 08:51 AM
ArTurf ArTurf is online now
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I do not claim to have a PHD's in agronomy. I do know that GD's advice has pretty much worked for me. Before taking his and some others advice I struggled with centipede. My take on university studies is not that they are wrong or right but sometimes they are done on a limited basis and not a LONG term deal. And for instance, our university is in the northern part of the state where centipede does not grow.

Book knowledge is great but sometimes there is that ability to "see & feel" small details that others do not. I seems to me GD has this ability. That he shares it so freely with us is a blessing.
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  #30  
Old 05-01-2013, 05:37 PM
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wildstarblazer wildstarblazer is offline
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I see homeowners around here who use store bought crap fertilizers and their lawns look nicer than ones that are maintained by pro spray companies. I think professionals try to make it all sound so scientific but at the end of the day it's results that matter. Buy a bag, spread it, water it. Done lol..
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