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1. David Clowers

   

   0 posts
   
   8/5/2011 4:08 PM

   Just got back some soil sample reports from UGA. All nutrient levels come back in line with the exception of K. Then have the ph levels on 4 greens have 5.3 to 5.9. Never had an issue with these numbers before. My greens are native push up with penncross. Knock on wood with this heat they're still in great shape with just some minor thinning on just a few. any ideas about these levels much appreciated.

   
   
   
   
2. Brett Morris

   

   0 posts
   
   8/5/2011 5:08 PM

   clowersd said: Just got back some soil sample reports from UGA. All nutrient levels come back in line with the exception of K. Then have the ph levels on 4 greens have 5.3 to 5.9. Never had an issue with these numbers before. My greens are native push up with penncross. Knock on wood with this heat they're still in great shape with just some minor thinning on just a few. any ideas about these levels much appreciated.

   
   
   K won't be influenced by low pH, as when pH drops then higher levels of other cations such as Fe and Al are more prominent. When pH becomes alkaline, the higher levels of Ca are prevalent. I would say it's just a low reading, perhaps influenced by potentially higher infiltration rates or lower OM%?

   
   
   
   
3. Wahlin Scott B

   
   8/5/2011 7:08 PM

   I have new USGA greens. When your CECs are in single digits: (1) aren't we really growing hydroponically and (2) isn't possible your pH could be changing minute to minute depending on your latest materials application?

   
   
   
   
4. Daryck Beetham

   

   2 posts
   
   8/6/2011 11:08 AM

   Check your base saturation percentages. If you can get your Bases to the ideal levels (Ca 60-70%) Mg (12-15%)
   K (3-6%) Na (2-4%) Traces (2-5%) Hydrogen (5-10%) then your PH will be right at that 6.3 level for maximum nutrient mobility. I believe to many people focus all of there attention to PH. The real question should be what is driving your PH. Joel Simmons jsimmons@soilfirst.com is very knowledgeable in soils and could help with any questions you may have.

   
   
   
   
5. Cecala Randal

   
   8/7/2011 6:08 AM

   Daryck,
   
   How do you get your hydrogen level right without focusing on pH? Soil pH is the negative log of hydrogen ions in solution.
   
   Sulfur, NH4, urea, products containing phosphoric acid like mono-potassium phosphate lower pH. Products that contain nitrates raise pH and lime does as well. Acid injection lowers pH of soil solution ( won't change pH of calcareous soil in lab test ). The plant cares about day to day pH of soil solution for nutrient availability.
   
   Microbes release H+ when oxidizing NH4, microbes release OH- in nitrification of nitrates
   
   photosynthesis produces OH- to raise pH, respiration produces H+ to lower pH
   
   I would like to learn of other pH driving forces

   
   
   
   
6. Rosenthal Gregg

   
   8/7/2011 8:08 AM

   Scott,
   
   You are correct new USGA greens are a unique growing environment, they are like hydroponic growing environment. requiring inputs of everything, retaining very little, until some organic matterand natural soil biology begins to build up in the sand to hold any nutrients. In my 4 grow-ins of new sand greens we constantly spoon feed those greens and when we did soil tests they were meaningless as numbers were so low like yours. It will take several years to get decent organic material in those pure sand greens, I used organic supplement products that had microorganisms, beneficial bacteria and then products to feed them. Soil Tech in Iowa was my source of these products Steve Nichols can help you he is a great source and specializes in these products. Look for his website.

   
   
   
   
7. Robert Crockett

   

   4 posts
   
   8/7/2011 5:08 PM

   wahlins said: I have new USGA greens. When your CECs are in single digits: (1) aren't we really growing hydroponically and (2) isn't possible your pH could be changing minute to minute depending on your latest materials application?

   
   
   Yes....USGA...greens..."Brand new" would be basically nuetral...No O.M.. unless you incorperate that into the green spec's...Irrigation water, I would think could be the only other inluence outside of what you apply.

   
   
   
   
8. Daryck Beetham

   

   2 posts
   
   8/11/2011 3:08 PM

   randc,
   
   pH is the negative log of hydrogen ions but within the realm of the base saturation model pH is the percentage of hydrogen. Understanding that all the cations that make up this model always and only add up to 100 we can simply shift what is low for what is high. Hydrogen is always flowing freely through the soil, usually as an H2O molecule, and that hydrogen will chemically react fairly quickly. You mention that lime raised pH but there are many cases that we will use high calcium limestone to lower pH. If Mg is driving the soil test and not calcium then when we add calcium to 100% something has to come off and in this case it will be what is most excessive – the Mg. In turn the hydrogen in solution has an opportunity to grab a colloidal site and the pH falls. Some soils are driven by high calcium, (where lime would not be advantageous), some by sodium, some by Mg… Sulfates lower pH in soil by knocking off a cation such as calcium, for example we us ammonium sulfate to lower pH, it knocks calcium (and Mn) off the soil colloid allowing hydrogen to grab the seat on the soil colloid and again lowering the pH by balancing the base saturation percentages.

   
   
   
   
9. Cecala Randal

   
   8/12/2011 4:08 AM

   Daryck,
   
   basis of pH H+ x OH- = 10^-14 it is about H+ and OH- not in H2O form
   carbonates species : CO3--, HCO3-, carbonic acid
   pH is about free ions precipitation ties up free ions
   Fe, Mn, Cu, & Zn for instance get tied up with high pH because they precipitate into insoluble hydroxides
   CEC is negative charge of soil colloids and organic matter as pH goes below 7 H and Al begin to adsorp to CEC
   sulfates do not lower pH sulfur lowers pH because it forms H2SO4 interacting with soil water
   cations are displaced in reverse order of their electrical attraction sodium goes first then K
   sulfate of ammonia reduces pH because microbes release H+ from NH4
   H+ doesn't adsorp to CEC until pH gets below 7
   photosynthesis raises pH, this is why your irrigation lake could go from 7.8 at 6 am to 8.5 at 7pm, the microbes respire during night to bring pH back down
   
   Carbonates do not drive pH, they are manipulated by it and act as buffer
   metabolic processes drive pH and this is an area that needs further exploration
   why can two waters with 250 mg/liter of bicarbonates have pH's of 6.5 and 8?
   A chemical composition or reaction is favoring the precipitation of either more OH- in the lower pH water or more H+ in the higher pH water or a combination of the two

   
   
   
   
10. Rosenthal Gregg

    
    8/12/2011 9:08 AM

    dont get too hung up on your organic chemistry books in the real world it will drive you to drink to much alcohol! Now thats some organic chemistry for ya too!

    
    
    
    
11. Daryck Beetham

    

    2 posts
    
    8/12/2011 9:08 AM

    randc,
    
    Ok...you obviously have me beat in soil chemistry. You have just blown my mind and I'm starting to feel stupid. I need to pull out the old text books so we can go to battle, however I think you're clearly going to win this one! My email address is beethamdaryck@yahoo.com if you feel up to it could you send me some info that will help me understand this a little more. Thanks!