I've only seen a couple of U of Del. Soil Test Reports, but none of them reported lead content. Are you sure that is a reading for lead?

Any chance you could post a picture of the test? If not, could you post the CEC reading? It will be in the same row as the reading for Mn and B, but to the right of them.

So the first sample is from the side of the house. The house sits “up” from the rest of the yard, so I’m guessing it’s basically subsoil that was backfilled. I planted a Metasequoia there. They like the acidity, but perhaps I’ll need to throw some P at them. My general thought was to remove all the turf in that entire area (30 X 30’) since it’s difficult to mow there anyway, put some compost and mulch there, and let it do it’s work over time as the tree grows.

The other tested area will be a vegetable garden. There is also an oak sapling at the edge of that area.

Thank you.

To begin, the numbers reported for P,K,Mg and Ca are Fertility Index Values (FIV). It's a way to covert measured amounts of a nutrient so that they can be scaled (e.g. graphed). Converting them back into lbs./acre (FYI, I have given the values for FIV of 100 a value selected by U of D):

P: FIV 5= 14.6lbs.-7.3ppm, a FIV of 100=205lbs./acre

K: FIV 118= 377.4lbs./acre-188.7ppm, a FIV of 100= 320lbs./acre

Mg: FIV 82= 214lbs/acre-107ppm, a FIV of 100= 261lbs/acre

Ca: FIV 70= 1199.9lbs./acre-600ppm, a FIV of 100= 1717lbs/acre

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pH: 4.8 pH is the gatekeeper for soils, as it has an effect on nutrient availability and soil life/microbes. Except ofr a few acid loving plants, the vast majority of plants do best in soil with a pH between 6 and 7. The ideal for lawn turf (grass) is 6.8. In a soil with pH below 5, aluminum toxicity becomes an issue and Mg. and P availability starts to become an issue. Calcium carbonate sources/ Ag. lime is used to raise pH. Dolomitic lime should only be used when Mg also needs to be raised.

Buffer pH: 7.8. This indicates a rather low amount of reserve soil acidity. This is common with low CEC soils like sandy soils. As this test was for an area where you are growing a lawn, you need to adjust only the root zone (top 4 inches. I would suggest applying 23lbs/thousand sq feet of a Ag lime equivalent lime. To avoid soil balance and turf issues, this can be applied in three 8lb. applications. Applications should be made at least 3mo. a.part and not made within 3 weeks of applying another amendment. Fall, at least 6 weeks before soil freezing and Spring, once the top 2 inches of soil has thowed, are the best times to apply.

P; 7.3 ppm. Very low. Most sufficiency levels recommend anywhere from 30 to 100 ppm. with a consensus of 50-100. This should be raised. Triple supper phosphate can be used when increased K levels are not desired. Otherwise, starter fertilizer can be employed. No more than one pound of P should be applied at a time, not any more often than every 3 mo. and not withing 3 weeks of the app. of another amendment. I recommend that for turf, you only adjust the top 4" of soil To reach a ppm of 50, you will only need to apply approximately 1lbs/k of P.

K: 188.7ppm. A bit high, but not so excessive that it should cause any other nutrient deficiencies and your Mg levels are low enough that K is not an issue with soil structure. Recommended sufficiency level is 110ppm. or slightly greater. No K additions are needed.

Mg and Ca. Mg: 107ppm, Ca: 600ppm. Mg:Ca ratio= 1:6. Minimum sufficiency levels are 50ppm for Mg and 350ppm for Ca. Other than when Mg:Ca ratios hit 1:1 or greater, there is no likelihood of Mg toxicity. Other than that, once you exceed the minimum levels, the biggest influence that Mg and Ca levels have is on soil structure. An Mg to Ca ration of 1:5 to 1:7 is considered ideal and tight soils are not an issue when Mg levels are less than 300ppm and or greate than 15% of total base saturation. Your Mg and Ca levels are sufficient andratios are fine and the increase in Ca (or Mg if you use Dolomitic lime) to adjust pH is not an issue (it almost never ever is).

All reported micro nutrients are sufficient, at least for turf. Besides adjusting them can be a bit of a pain, but can be done.

CEC: 7.8. A value commonly indicative of sandy silt with lower OM and very little, if any clay. The buffer pH supports this. Most likely reason that you perceive clay is poor soil tilth and compaction.

OM: 3.8% mediumish. Ideal should be 6-8 with an absolute max of 10. OM has an influence on CEC and soil tilth. You can add OM once or twice a year. Applying alfalfa will help raise OM and help raise Boron and it won't hurt to raise your B to .5-1ppm from its current .45ppm. Mulch mow and mulch Fall leaves. Best strategy for improved soil OM and soil tilth is to promote a robost root mass.

I wonder if this soil is K-based clay, maybe kaolinite. Academic really. Here in MO our clays are derived from decomposed limestone, so we have very high Ca levels. In any case avoid fertilizers with K content. Like don't use 12-12-12 even though you may need the N and P.

Clay holds tightly to phosphate so it's probably there, just not very soluble. Once you get the levels up, try not to overshoot. i.e. test again in a few years and don't add P endlessly because it will become excessive even with a few years of nothing but compost amendment.

Sorry hairmetal. It appears you made a post while I was writing. For trees, where most of the feeder roots are in the top 18" of soil, surface application of amendments are going to be glacial slow in reaching down to 18". Maybe you could inject nutrients? Not my area of expertise. :(

If you want an analysis of the second area (garden?), let me know and I'll do it later.

Here’s a question:

As far as lime, how far does it “travel?” If we accept at the moment that my soil is indeed a silt loam, how much lime do I need, and, how far away from the rootzone of acid-lovers like azaleas, blueberries, even red maple or pin oak, etc do I need to stay to where the lime won’t “runoff”, especially if they’re downhill from a limed area?

I was also thinking my pH goals staying on the lower side, maybe upper 5’s, so I don’t accidentally go too high for other things I’m growing, but if I have a planting of azaleas that’s a bit downhill, how far away do I need to stay from them with the lime?

Hairmetal,

No offense, but you need more focus or you're going to just spin your wheels.

Nutrients should be somewhat customized to the crop.

Separate soil test should be done for each area and for any area with significant difference in soil. One for the lawn, one for the vegetable garden, one for a blueberry patch and one for flower gardens, etc.

When testing for lawns, the test holes should be 4" deep and a slice of soil from 1" down to 4" should be included in the sample. Sample should include soil from test holes 15 to 20feet apart throughout the lawn area. If a significant area of lawn has a soil of a different texture or color, it should be tested separately.

Gardens (vegetable or flower beds) should be tested to a depth of 6-8" using a slice from 1 to 6 or 8" deep. Sampling should be taken from more than one hole -at least 3-4 sites, depending on the size of the area.

There are just too many variables (precipitation, soil water content, soil texture (percolation), slope, pooling, etc.) to give any kind of meaningful advice regarding your lime question. On a flat surface, lime will "travel" very very little (as in negligible) laterally.

If the soil test lab is any good they will make recommendations about what might ned to be added to the soil to correct any deficiencies. On one report above I see the recommendation to spread 50 pounds of ground limestone per 1,00 square feet.

Had you had the soil test done by your University of Maryland you could ask the people at you local office of the Maryland Cooperative Extension Service, although they may still offer some help.

kimmq is kimmsr