Soil test results and adding fertilizer

16 years ago

My soil test is in and I have a few questions. I need to add a substantial ammount of P and K. My lawn is already dead from RU last week- Too early but I couldn't wait to get started. I am probably 3+ weeks away from seeding KBG. Should I apply the full P and K recommendations now? I plan to later scalp, Rake, Areate, starter fertilizer, seed, and 1/4" compost. My main concern was not having the fertilizer too concentrated. The extension mentioned the max recommended rates to apply at once without tilling are about half of what I need. Will the 3 weeks wait and areation make a difference?

SOIL NUTRIENT LEVELS

Soil pH 6.5

Phosphorus 17ppm

Potassium 80ppm

Organic Matter 2.6%

RECOMMENDATIONS:Prior to planting, incorporate the following into the top 4 to 6 inches of soil

Limestone: NONE

Phosphate: 24 lb/1000 square feet of triple superphosphate (0-46-0)

Potash: 7 lb/1000 square feet of muriate of potash (0-0-60)

At time of planting, use ONE of starter fertilizer materials listed below at recommended rate.

18-6-6 5.5 lb per 1000 square feet

or

13-13-13 7.5

Thanks for the help!

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Comments (4)

texas_weed
16 years ago
Something is very wrong here. I will give you an example. Your P (phosphorous) from your results is 17 ppm. The optimum, ideal or medium range is 10 to 20 ppm. Which means your P level is dead perfect and you do not need any P what so ever..

Now one to the recommendations they say add 24-pounds of 0-46-0 of superphosphate with translates to 12-pounds of phosphorous per 1000/ft2 which is enough to poison you ground for decades.

Your K level is 80 ppm which is the low range. Optimum range is 175 to 250. Again they recommend way too much product to correct. From my charts you only need 4-pounds of muriate of potash per 1000/ft2.

To add injury to insult they tell you to add even more P&K by using starter fertilizer. Somebody is smoking crack.

Just based on the test results assuming they are correct ( I wouldn't assume they are based on recomendations), I would use 10-0-20 at a rate of 10-pounds per 1000/ft2 now and repeat one more time in 6-weeks. After that switch to nitrogen only fertlizer until next season, then retest before adding any P or K
grass_man
Original Author
16 years ago
Thanks for the reply Texas. I am a little confused. On another thread you gave these ranges as "normals". Are we talking about the same units of measurement? You are correct in that they did recommend a total ammendment of 11 #/1000 of P2O5 and 4#/1000 of K2O

_______________________________________________________
RE: Help with Soil Test Results (Follow-Up #2)
posted by: texas-weed on 07.26.2007 at 12:41 pm in Lawn Care Forum
I will be brief. The short answer is lay off the Phosphorous this year and next.
To clue you in here are some ranges for optimum turf conditions so you can see where you are at.

PH 6.3 to 7.2
P = Phosphorous = 50 to 75
K = Pot Ash = Potassium = 150 to 250
Ca = Calcium 800 to 16000
Mg = 150 to 2,000
CEC sandy texture = 1 to 5
CEC silts = 5 to 20
CEC clay = 20+
__________________________________________

Here is a link the complete report from PSU. Sorry, I could not figure out how to hyperlink or copy/paste a pdf doc.

http://146.186.216.108/pdf/2007/2028608401816.pdf
Thanks again for any thoughts
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Adding according to the soil test recommendations will give you a good, general level of nutrients which will start your plants off well. Most of the nutrients are fairly stable in the soil and won't disappear over the summer, other than uptake by the plants. Nitrogen, however, is fairly easy to leach out of the ground with excess moisture and can gasify under some conditions. Your recommendations for a general garden may need some adjustments depending on the favorite nutrients of the plants you are growing. As mentioned, corn loves nitrogen, and you would likely want to side dress with some additional nitrogen when the corn is about 2 feet high. Corn, however, isn't the only nitrogen lover although it is extremely transparent in telegraphing its nutrient status so shortages become quickly and easily visible. Pretty much everything other than legumes (which use bacteria to make their own) love nitrogen too, and even legumes can respond to nitrogen. Watch your plants around 6-8 weeks after planting and if there are any signs of potential shortage or weaker/slower growth, then side dress with some additional nitrogen. After mid summer, let the plants use up what is available in the soil. You don't want to fertilize so heavily that you leave a lot of available nitrogen in the soil at the end of the season where it can leach to groundwater or anywhere else.
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You're pH of 7.6 really isn't too bad for most vegetables but a downward adjustment would increase nutrient availability and, most likely, yield. I would add sulfur prior to the next cropping cycle. I would do about 15 lbs. per 1000 sq. ft. tilled to a depth of 6 to 8 inches. That will adjust your pH downward over time and it will happen pretty dang slowly. Remember that lime buffers against that change and since you have a lot of it, you're soil is strongly buffered. Clay is another thing that will buffer against pH changes and if you have a clay soil, that will also work against your downward pH adjustment. Another test next year to see where you're at would be in order. For nitrogen, as mentioned above, blood meal would be a good choice. 10 to 15 lbs. per 1000 sq. ft. tilled to the same depth should be about right for new plants. If you're looking for one material that that will provide nitrogen while acidifying, blood meal will do virtually nothing, particularly considering your buffering capacity. You would have to move to synthetics to do what you have in mind. Two options would be ammonium sulfate (21-0-0) and sulfur coated urea, which is usually around (40-0-0). Ammonium sulfate = fast release, sulfur coated urea = slow release. Good rates would be 7 lbs. and 5 lbs. per 1000 sq. ft., respectively. Both of those would also give your sulfur level a little boost as well. But be aware that the pH change would rely on regular re-application of those acidifying fertilizers over a very loooooong time (again, buffer). The sulfur really would be a better route for you. On a side note, as your instincts have already told you, BER is not always due to low calcium in the soil. Un-even watering (too wet, followed by too dry, repeat) is usually what leads to the problem. Yes, it's a calcium deficiency in the tissue but variances in water availability to the plant plays a major role in the uptake of that nutrient.
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I'm a doofus. I missed the fact that the analysis was conducted on your 2/3 soil to 1/3 mushroom compost blend. Anyway, my comment about 0.0 ppm available nitrogen stands. I think it's a lab error. My comments about salinity also stand because we don't know the starting salinity of the compost or the soil. That being said, the final blend is 23% O.M. by dry weight, which is super high. If the mushroom compost was 1/3 of the final blend by volume, that would put you in the 7 to 8% organic range by dry weight if mixed with a mineral soil. And that's if the compost itself were high in organic material. (The analyses I looked at for the compost ranged from about 30 to 60% O.M. by dry weight). So, it would be a safe bet that your 4-way soil is probably around 15% O.M. by dry weight or a little higher. That means that it was probably about 50% to 60% organic material by volume and who the heck knows what that O.M. was. If it was raw wood chips, you would still have some available nitrogen in the analysis, but potentially not enough to balance carbon and it's feasible that you do indeed have a nitrogen draw issue. Or, if it has a heavy manure component, that could contribute to salts. (even a high quality greenwaste compost will often have a salinity level of 5 to 7 dS/m). Also consider that such a high amount of organic matter has the potential to hold too much water, especially if drainage isn't all that great at the bottom of the planters.
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Thanks for the responses y'all! toxcrusadr: I do try to rotate a I can given the limited space, but some things (e.g., tomatoes) can only shift across a few squares in each bed given how the beds are arranged. Given the poor germination this year, I suppose parts of each bed are effectively fallow, but never a whole bed and I have not grown any covers or green manures. gardengal48: Why do you recommend against the sand? I was thinking that some grain size variation would be helpful as I try to build up a true mineral fraction. I head read that perlite will swim to the surface over time, which is why I was not thinking of using it. I don't know that I have seen pumice around the Twin Cities...What grain size were you thinking? My sense is that the first year with the Mel's Mix was the best and it has declined steadily since then, but certainly many folks on the SFG forum swear by it! What about mixing in pine bark fines if I can find them? I have seen some threads discussing their benefits and it seems like they could help lighten the soil, increase aeration and aeration, and, at least according to some, won't particularly tie up N. Plus they might help decrease the pH a bit. David
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texas_weed
16 years ago
Optimum levels depend on the test method used of Bray or Colwell, soil type by state, and which source of info you choose to use. The point is the P recommendations you received are off the charts of reason and I don't understand especially from PSU or any other university for that matter. Maybe I am missing something, so wait and let others chime in and either confirm or point out my oversight.

Any lawn or garden book worth their salt will tell you never to add more than 2 pounds of P in any one application, so you can imagine my shock and awe of 12-pounds all at once.

At any rate you are safe to add N and K now, but not that much P.
grass_man
Original Author
16 years ago
The PSU website is really nice. I was tinkering with my results and was able to change the recommendation for "Home lawn- maintain" here is the output. I also called and spoke with someone from the lab.

Agricultural Analytical Services Laboratory

Penn State University

Soil Test Report

Recommendation Change

Soil Test Report For:

Sample Identification:

Lab ID: S07-01816

Field ID: FR LAWN

Report Date: 07/25/2007

Soil Test Results:

pH: 6.5

P (ppm):

K (ppm): 80

Organic Matter (%): 2.58

Recommendations

Turf Use: Home Lawn-Maintain

Grass Species: KENTUCKY BLUEGRASS

Limestone (lb/1000 sq ft): NONE

Nitrogen (lb/1000 sq ft): 3-4

Phosphate (P2O5) (lb/1000 sq ft): 3

Potash (K2O) (lb/1000 sq ft): 3

Org. Matter (cu yd/1000 sq ft): 2
_________________________________________________

They basically are agreeing with you that Phosphate be limited in one application. Their higher recommendations mandate that they are tilled into the top 4-6 inches.

The Phosphorus range they quoted for my conditions is 75 - 100 ppm. She also mentioned (this is where she lost me) about the differences between phosphorus and phosphate (P2O5).

Anyway, since I will not be tilling the max rate I can apply is 5lbs P2O5/1000 (9 # of 0-46-0) I think that this is what I will go with. Hopefully the areation will help get it down into the root zone.

Thanks again Texas

Soil test results and adding fertilizer

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