Your interpretation of soil test

General Gardening
#1

What do you guys think?

This is previously uncultivated rangeland. Sample taken next to a well-mulched (wood chips) peach tree that did not thrive in its unamended planting hole.

I have plenty of wood chip compost (over a yard) that I made with urea and some ammonium sulfate. I am not organic.

PH 6.3

Phosphorus 31.1 Optimum range 4-14

Potassium 412 Optimum range 100-600

Calcium 1295 Optimum range 1000-1500

Magnesium 287 Optimum range 40-120

Sulfur 26.1 Optimum >10.

Boron 0.9 Optimum range 0.1-0.5

Manganeze 9.1 Optimum 1.1-6.3

Zinc 0.7 Optimum 1.0-7.6

Copper 0.1 Optimum 0.3 -0.6

Iron 0.5 Optimum 2.7-9.4

Aluminum 9 Optimum <75

Lead 0.3 < 22

Cation Exch. Capacity, meq/ 100g 12.o Optimum ____

Exch. Acidity, Meq/100 g 2.1

Base Saturation, %

Calcium Base Saturation 54 Optimum 50-80

Magnesium Base Saturation 20 Optimum 10-30

Potassium Base Saturation 9 optimum 2.0-7.0

Scoop Density, g/cc 1.21 Optimum ______________

#2

Looks like good soil in most regards. Don’t apply any more Mn. Mine tests 15 and it’s nearly toxic.

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#3

I agree with Fruitnut
Asumming you are growing fruit trees.
May want to up the phosphorus to Near 100 for better legume cover.and or garden
Not sure why they state 4-14 as the optimum range for phosphorous ,?
This seems low to me , at least for a garden, row crops, legumes etc
May be ok for trees, I would up it.
Or they may be using a different scale than I am familiar with, ( no units)

You say you got the sample near a peach tree
For the best representitive values of an area, it’s best to do many samples ,20 or so , from a large area, dry ,blend together ,and send it off.
As "one " sample ( one shovel full , from one area , ) is not representative of really anything except the dirt you are now missing

Maybe do samples away from your mulched peach tree as well.
To give you a baseline of what you are starting with ,befor the soil improvement of mulch added nutrients etc.

#4

Unfortunately the sample I sent in from the mulched tree didn’t get done yet. I hope it’s not lost.

Since the sample was from an uncultivated piece of land I expect it was good baseline.

I really didn’t have a good understanding of my soil’s structure. I just assumed that it was alkaline adobe. I wasn’t expecting to see PH below 7.

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#5

pH is fine.

I agree with Hillbilly that 4-14ppm would not be optimum for phos for peach trees if you are talking bray1 equivalent (there are different phos tests). For peaches, about 30 ppm is adequate, so you are good there.

Potassium is high. The highest recs I’ve seen on K are in the 250 range, so you are way over (despite what your lab test says).

Ca is a little low, imo. Ca needs to be about 2500.

Mg is obviously high

S is high

B is OK.

Mn is high

Zn is low. It’s not uncommon for peach trees to show Zn deficiency in the West.

Cu is a little low, but I wouldn’t worry about it. Spray a little copper for leaf curl and the soil will quickly increase in Cu.

Iron is low

CEC is a little low, but not alarming.

If it were me, I’d probably lime the soil a bit. It would bring up the Ca and pH both. I’d probably add a small amount of Zn (generally sold as zinc phosphate) It’s regularly sold in 50 lb bags, but depending on your orchard size, that would be way more than you’d need. I’d also add a little iron.

Other than that, it looks like pretty good soil.

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#6

OK. Iron and Zinc.

Iron deficiency is a small surprise. No obvious signs of chlorosis. The green of the leaves just kind of waxed and waned normally. Just goes to show that you can’t eyeball it.

I don’t think I can bring myself to liming the soil, even if I could find a bag of lime within a hundred miles of here. At least I don’t have to feel guilty about using Calcium Nitrate.

The tip about copper fungicide as a source of copper is helpful. I was wondering how I would address that.

No need for S additions.

My assumption is that the Phosphorus scale used is different than what you all are used to seeing given my middle-high reading. I’ll leave it alone for now.

Looks like my practice of making my compost out of wood chips and urea was accidentally a good strategy. Had I used manures, my P and K levels would be excessive.

Glad I didn’t mindlessly fertilize with an all-purpose fertilizer.

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#7

Not my thread, but a relevant question: We got our soil test reports back from last month. It looks like all the liming I did really helped get the pH up in some of our more acidic plots, which are higher up on the hill. Prob need to add some more fert to get the P and K up, but it’s better than it was before in those plots.

One test result is bothering me tho. In the plot furthest down the hill from us, the P is at 609/lb/acre, the K is 332, Ca is 2315. We grew corn and beans in this plot last year, and had a very good harvest of corn, and the beans did well also, but could’ve benefitted from being on a trellis. Last year before any amendments, the P was 516, K was 375, Ca was 2495. The amendments to this 1500 sq ft plot was 30lb of 10-10-10, and 40lb of dolomitic lime.

Another plot, also further down the hill, is below the barn, and it’s results were P=175, K=383, Ca=2272. Previous year, P=169, K=462, Ca=1462. Amendments to this 1500sq ft plot were 80lb dolomite, 50lb ag lime, 20lb of 10-10-10. Those numbers are high, but a bit more reasonable. My guess for the higher nute levels were because it used to be a pasture for a horse and cattle. So lots of manure in that area over the years.

Just an FYI, the CEC of these plots are about 11-12.

Why would the P be so high in the first plot? My wife said that area used to be a place where they grew a garden many years ago. She said they used to dump a lot of wood ash onto it in the winter, as that was their main heat source. I could see how maybe thats why the K is so high because there’s more of potash in wood ash, but that hasn’t been done in prob ten years, and you’d think it’d leach out some since then.

Our house is about 150ft up the hill from this plot. We have a septic tank and multi level drain field down the hill and to the left of the tank. The system was installed about 15 years ago, and had to pass the county’s inspection. We had the tank drained about 3 years ago, and the septic dude said it was just half full.

Could the stuff from this drain field be the reason for the high P in this plot? That is, could it be leaching out and showing up in this plot? And if so, is it really a good idea to be growing food there? The plot is not totally directly below the drain field.

Thanks.

#8

The high P is probably from applying too much fertilizer. People throw out stuff like 10-10-10 when P is already 10x critical level. You just did that and raised P from 516 to 609. Not being critical but just looking at what you stated.

My garden area tested 477 while the greenhouse tests 51 just 30 ft apart. I haven’t applied P to either one. Someone else did it before I moved in 13 yrs ago. They also applied Mn to nearly toxic levels. The Mn is dangerous. Excess P can cause issues with uptake of other nutrients but won’t poison the plant by itself.

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#9

I understand that P is slow to leach out, compared to N and K? I won’t be adding any more triple ten this year. I might add maybe a 50lb bag of lime, and perhaps some 27-0-0 that I have.

Perhaps I should maybe concentrate on crops that are heavy P feeders? I don’t know what they are so I might need to do some research.

Is the fact about the drain field an issue? Would it cause the P to be too high? And is it safe to grow things there?

#10

Nitrogen leaches out, P and K are slow to leach esp P. You can’t really crop P out. Plants don’t use enough. Just live with it and don’t add more. It’s probably less of an issue with garden crops than fruit trees.

I doubt the drain field is the issue. P won’t move thru the soil with water. It’s tried up by clay and organic matter. So it won’t move far from the drain lines.

It’s safe to eat crops grown in that area.

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#11

Thanks for all the replies. My wife said that the first plot is so fertile because it used to be the main garden years ago. They did use fertilizers, but also dumped various types of cow or chicken manure on it, along with the wood ash. Could the manure be a source of the high P levels?

I was considering planting my new pluots close to the plot down by the barn. (Levels mentioned above). Considering the high P, K, Mg and Ca levels there, would this fertility be an issue? The pH is about 6.5.

I guess my main concern regarding the proximity of the drain field wasn’t the excess P or any other nutrient, but the possibility of bacterial or other contamination from any human waste?

#12

Human waste could be buried around fruit trees without an issue. That’s as long as it’s completely buried. Disease organisms won’t move thru the roots and into the fruit. So I don’t see any issues in that regard for a sewage drain field.

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