Raining steady here today.
I got my soil tests back dated May 1. Took a quick look and decided on my fertilizer (12-0-12) for this year and bought enough for the season a week or two ago, but I haven't sat down to do any more in-depth analysis until now.
Some background on my fertilizer program/history: In 2016, I applied 10-10-10 (1 lb/M) June 1 and September 1. In 2017, Mid April, I applied 11-28-18 at the rate of .5 lbs/M of P2O5 to promote some fill-in. June 1, I applied 6-2-0 Milo at 1+ lbs/M N rate. Applied 46-0-0 Sept 1 at 1 lb/M and Witnerized with 46-0-0 late November at about 2 lb/M N rate. In prior years, except for 2015 (no Milo), My program was to apply 10-10-10 Late April (optional, but most years), June 1, September 1 and October 1. Winterizer late November/early December at 2 lb/M N rate. Milo anytime the urge struck me, but never on a day not ending in the letter "Y." (in the early years I could swear that Milo was 6-4-0, but maybe not).
I plan on applying 5 lbs/M of N this year. June 1, September 1, October 1 and a winterizer.
Applying the "simplified" method for determining optimal fertilization, for 5 Lbs/M of N, my KBH will need about 1.15 lbs/M of P2)5 and 3 lbs/M of K2O this growing season.
My target ranges and analysis:
pH 6.1. I want to stay slightly below 6.5, as I do think it helps prevent disease issues and micro-nutrient availability, but I don't want to drop below 6 to avoid any chance of Mn issues plus promote a better environment for micro life. Debating using 5-10 lbs/M of a fast acting lime. Hate to though as I want to avoid issues with K levels.
Bray P1 (phosphorous)
Sufficiency Range (ppm): 15-30
Test reported value: 120 ppm.
With a Bray P2 value of 125 ppm, it indicates that most of the available P is very liable with not much additional held in liable reserve.
P1 at 120 ppm is more than a wee high. That's about 550 lbs/acre of P2O5. When I started, I fell into the trap of thinking I wanted all my nutrients to be at some imaginary maximum rate. For P, I selected a M3 tested target of 100 ppm based on the fertility indexes used by the University of Delaware (Why Delaware? Because I couldn't find one higher.) The other test I bought, uses M3 extraction for P and it reports P at 169 ppm, so however you cut it, I overshot. Fortunately, I haven't experienced any real detriments other than a slight loss in color.
I know better now, my target for for P for the simplified optimal method of fertilizing should be about 22 ppm. I've got about 10 lbs/M of P2O5 too much. My soil P "bank" account is over-funded.
As the soil contains so much P, I wont be applying any P2O5 this year or for the next couple of years. I will let my turf withdraw its P needs form the soil bank and get those levels down to less than 30 ppm. It will be interesting to see how quickly (more like how long) that happens.
Ammonium Acetate Nutrient extraction ranges (Ca, Mg, K and S)
Ca: 500-750
Mg: 140-250, 100-200 for sands
K: 100-235, 75-175 for sands
S: 30-60
My soil is a sandy silt, much more silt than sand.
Reported Ca and Mg values are well within or above recommended ranges.
Soil reported K values is 119 ppm. I'd like to see that closer to 200 ppm or at least above 170.
I'll be applying 5 lbs/M of N, so my turf is going to use between .5 and 1 lb/M of K this growing season. That's 3 lbs/M of K2O at the low use rate and 6 lbs/M at the high end use rate. I'll start with expecting the low end rate usage and see where I am next year as I'm not finding a local source for SOP or even MOP for that matter. After next year's test I'll have a better idea of my turfs K use rate and can adjust the amount of extra K that I need to get to 200 ppm. Seeing as using the 12-0-12, I'll be adding 5 lbs of K2O, that should help.Adding lime for pH is not going to help this.
Reported value for S is 7 ppm (although I might need to consider some variance with the suggested range as Midwest only reports this as a low and not a very low, probably due to their use of ICAP instrumentation for measurement) I want to raise this to above 30 ppm.
This will be an issue as I don't have SOP available which precludes using AS for my N too. I could use Gypsum (but I'm already slightly raising Ca levels by adding Ca with my pH adjustment) or Epsom salts, but that will create a conflict in keeping my K levels within the ranges and using elemental sulfur, which I have available, will lower my pH, which at 6.1, is already lower than I want. Po-Mag, is probably my best option as I believe I can find that locally. It's a wash on the K/Mg issue and the Mg might help with my color as I do have some room to raise it. This is a real pisser off-er for me.
DTPA
Fe: 10-15
Cu: >1
Zn: >2
Mn: 2-5, 5-15, if soil pH >7
DTPA Sorbitol (B)
B: 0.4-2.0
Test reported values for Copper and Zinc are good, I chose to ignore the iron range, especially with my high P levels. Mn reported value is 13, which is high, but should not be a problem with my pH at 6.1 (heck, even if my pH was less than 5, I doubt this would be much of an issue) and as I am raising my pH that should reduce available Mn. B is pretty low at reported value of 0.4, will need to keep an eye on this on next years test. Saving grace: I always say: don't mess with micros. Will watch for any signs of deficiencies.
Recap:
Make my mind up about pH adjustment. Probably will adjust. Need a fast acting lime from HD or Lowes.
Raise K. Use the 12-0-12 for all 5 feedings (including the winterizer. No urea this year.
Raise S. Find Po-Mag. HD or Lowes, if not, then the local garden shop maybe.
