Another soil sample for review

General Fruit Growing
1

Since my previous thread where getting a new soil test was suggested has drifted over to other topics, I am starting a new thread.

I am on the 8b/9a line in Louisiana, soil is a moderately well drained fine sandy loam soil (Beauregard soil series) according to the local soil survey. I grow blueberries, citrus, thornless blackberries, peaches, plums, pluots pears, etc. With the stonefruit and pears being my most recent / current plantings.

Listed below are the results from the current soil sample for samples taken from an un-augmented area (5 acre yard) where I am planting the new pears and stone fruit.

pH 5.82
Phosphorus 8.24
Potassium 28.47
Calcium 307.12
Magnesium 34.30
Sodium 6.71
Sulfur 6.77
Copper 0.33
Zinc 1.13

all values other than pH are in ppm
% Organic matter 1.79%

I took 2 other sets of samples in the area where I am growing blueberries and citrus, where fertilizers have been used in recent years, there results were overall very similar with some slightly higher values as might be expected, except for Sulfur in the blueberry sample with was in the 650 range (sulfur has been added over the last few years) , as well as a pH of 5.22, and Magnesium in the Citrus sample which measured 54, though Epsom Salts have been used there due to known low Magnesium in area soils.

What are your fertilizer recommendations (conventional or organic) ?

2

Issac,

As you probably know, P, K, Ca, and organic matter are all very very low. Honestly, I’m not trying to make you feel bad, but this looks like really poor soil.

My suggestions are based on commercial recommendations. Many backyard growers grow fruit on very poor soil, so it depends on your goal. Since you went to the trouble of doing a soil test, I assume you are looking for optimal soil recs.

It’s going to be difficult to get those things up right away. As a general guideline for fruit trees you want to see the P at about 25 (if your report shows Bray1 P - make sure you check that). Your soil probably weighs somewhere in the 3 mil pound range for a foot acre of soil. So if you add 3 lbs. per acre of P, you will increase your soil by 1ppm of P. So to get the soil to 25, you would need to add about 50 lbs. of P per acre. If you don’t have an acre to fertilize you can just do the math to get the corresponding amount for the square footage. Around here you can buy monoammonium phosphate in 50 lb bags. A couple bags (about 50% P) would do an acre.

If you are looking at K. You’d want it around 200 or so, which equates to you needing to add about 500 lbs. per acre. The problem is you can’t add that all at once, if you use potassium chloride (aka potash - about 50% K), which is the cheapest, you’d be adding too much chloride. You’d have to add it over several years. About 1/2 ton per acre total.

You could use potassium sulfate, but that adds more sulfur than you need and also lowers the pH, which you don’t need for fruit trees like apples, peaches.

Potassium nitrate would be the best option, if you can find it.

Ca needs to up around 2500. If you are talking straight ag lime, then it’s about 40% Ca, so you’d need to add about (Edit) 8 tons per acre. You won’t be able to add that all at once because it would probably raise the pH too much. You might also consider a little dolomite lime as some of a substitute, because your Mg is low (should be around 350). Dolomite also contains Mg. Btw, don’t use any lime around your blueberries.

Zinc is a little low as well. It should be around 4. You could add a small amount of zinc sulfate About 12 lbs. of zinc sulfate per acre would do it.

Organic matter is very low, but trees can be grown on very little organic matter. Still it’s low enough, your trees would do better to add some. Stable waste, or wood chips or straw on top of the soil will slowly bring up organic matter.

Wood chips, stable waste etc. will add some of the other nutrients, but not as much as you might think, so I would ignore any benefits to nutrients as a corrective measure, but as I mentioned your soil would benefit greatly from the extra organic matter.

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3

Thanks for the reply, I will check with the local ag fertilizer business (owned by a step-cousin) in the next couple of days on what they stock. I primarily intend to fertilize the fruit and ornamental trees, not the grass which seems to do fine as is. For the most part I have a good idea on what needs to be done on the citrus and the blueberries (as long as I ignore the suggestion to add Ammonium Nitrate for the blueberries that came with the soil report). For the organic matter issue, I plan to mulch with pine bark mulch which is available around here for about $1.50 for a 50 pound sack, alternatively I can get a pickup truck load of wood chips from one of the local chip mills for $15-$20

As you said soil is poor in nutrients, though at least it is a well draining fine sandy loam soil, and I would rather have pH a bit low rather than high.

Any thoughts on organic options, chicken litter in particular as I have a bulk source for it too.

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PS the test procedures are listed as Melich3 / ICP, not as Bray1 if that makes a difference, one of the other samples shows an even lower reading for P at 4.87

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Wow, that is some poor soil, I wonder why all those numbers are so low? Could it be the sandy soil leaching out a lot of nutrients? I’m surprised your pH isn’t lower. Those Ca, K, P and Mg levels are crazy low.

I’m curious how your other plants/trees have done in your soil? I recall from other posts that you had trouble with some PrimeArk blackberries living for very long. I wonder if it had to do with the soil?

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Both test give the same results on acidic soils, so you are looking for about 25 ppm as an optimum for that number.

I did a quick google for analysis of chicken litter, and apparently it varies somewhat, but a general baseline might be 3% of N, P, K each (As mentioned generally organic amendments don’t have near the amount of macro nutrients, that’s not a bad thing, just means you have to add more to get some of the macros up.)

At about 3% P, you’d need to add about a ton of chicken litter per acre.

To get the K up to 200, you need to add about 8.5 tons of litter per acre, but that would blow your N and P off the charts. Because of that I wouldn’t try to use too much chicken litter to correct K. If you do use chicken litter, you may not have to add any additional P.

Btw, I just noticed I made a mistake in one of the calculations above. I said 2.5 tons of ag lime to get the Ca up to 2500. Actually it would take about 8 tons per acre. Again this is too much to add all at once. And you’ll need to do future soil tests to monitor the pH.

As I mentioned, it’s going to take some time to bring the soil up.

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I guess one step at a time is all I can do.

As to the stuff that is growing, there are 3 mature (20+ year old) unknown pear trees, they range from about 15-25 ft tall, unknown european pears, they are productive, but the the squirrels get all the fruit ( when it gets to be about golf ball size, they take one bite, yuck not ready, how about this one, …) I also have several citrus trees 2 of which are 15+ years old and 15+ ft wide/high, and a similar size/age Fig tree. These are all productive, though the soil makeup is close to the published ideal soil numbers for citrus by the University of Florida, though the P value is still low, they are also located near the septic tank field lines which may have an effect. Blackberries are generally good, I am growing 5 thornless varieties, the only failing ones are Prime Ark Freedoms, Prime Ark Travelers are only doing moderately well, Blackberries will seem to grow anywhere they can get nitrogen though. I also have a couple of 20+ year old rabbit eye blueberries, that if not thriving are surviving reasonably well, I just started pruning and fertilizing them a couple of years ago after many years of neglect. I have also added another dozen blueberry bushes, performance on them varies, but they have soil that has been augmented. This does not count the young fruit trees I have planted in the last couple of years, all of which are still surviving if not thriving.

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Poor soil can be a blessing for a home grower- especially in the humid region. Good corn soil, deep and rich, creates too much vigor, reducing brix and fruit color and complicating pruning and training. The worst soil can quickly be brought up to the requirement for fruit trees.

I’ve converted almost pure clay subsoil into a very productive orchard where trees can’t send much root into the unamended clay. I won’t explain what I did with this soil because yours is the opposite- but I’ve also grown productive orchards in almost pure sand- I love very sandy soil because it provides some control of how much water the trees get when fruit is ripening so it is easier to achieve highest quality fruit where it rains during the growing season.

Sand is easy to blend in compost- you only need work it into the top 6-10 inches of soil in 6-7’ diameter rings for each tree. Rent a commercial 10hp roto-hoe or labor equipped with cultivating (potato) forks to blend in about a third yard of good compost per tree (masonry supply yards often deliver it by the yard). This will instantly alter you soil and it will test completely differently.

If you don’t want to do that, it probably isn’t necessary anyway- a couple inches of compost covered by 3-4 inches of arborist wood chips spread over a similar area accomplishes more or less the same thing. Feeder roots will come right into the compost and rotting wood chips.

Besides lime, the only nutrient you really may need to add before planting is P because it isn’t mobile in the soil, but it actually is quite mobile by way of mychorizal fungus which should thrive in the wood chips. Of all the scores of orchards I’ve managed over the years, I’ve never observed a P deficiency- probably because of mychorizal relationships- strands of fungus actually connect to roots and deliver P and some other nutrients in exchange for carbos from the tree. P levels can be extremely low without trees suffering deficiency because of this. Desired P levels are actually based on what serves annual crops and not fruit trees.

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9

That’s very true. Blackberries will grow on just about any soil. Pears are pretty tough too.

It may not be necessary to do anything. I prefaced my comments that I was basing suggestions on commercial recs, which are generally looking for max yield. But I will mention that your soil is some of the most deficient I’ve seen posted on a forum.

If you are happy with the performance you’ve seen so far, there’s no need to change anything. You may get some Ca issues with apples (if you intend to grow them) with pH low and Ca, Zn low, but you could always wait and see.

I really don’t know much about citrus (obviously too cold for that where I’m at).

Most people who grow fruit trees never do any soil test, so you are already ahead of the curve there.

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I don’t know who did your soil test, but the ones that I have done by Clemson, not only gives a numerical value for each element, but also shows if you are Low, Medium, Sufficient, High, or Excessive for the crop you are growing. It also gives specific recommendations needed for the crop you are growing, and a number to call, for organic gardening recommendations. You are also encouraged to call your county agent, who will be glad to discuss the results of the test with you and give recommendations beyond the general ones provided with the test. They also have special experienced agents for different types of crops that can give more detailed recommendations.

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As a plan of action I think it is probably best to take this slow, and build up over multiple years and address the biggest issues first:

Let me know what you think of this plan of action, assuming available fertilizers:

Dolomite Lime targeting a pH of 6.0 for the general open yard area (4 or the 5 acres) with a secondary effect on Calcium and Magnesium

Address the low Phosphorous with an Ammonium Phosphate fertilize (I need to do more research on which one MAP or DAP, as to which has the least acidic effect on pH, etc.), this would have the added benefit of a bit of a Nitrogen boost for the grass, trees, etc.

Then Potassium Nitrate to address the Potassium deficiency and boost Nitrogen

I am just not sure how slow to go on all this, or if it is worth it to have a fertilizer truck out and have it professional spread, at least for the front part of the yard, the front yard is long and narrow (tapered wedge 200-300 ft wide by about 700 ft long, mostly open, but with about a dozen large trees, and maybe 3 dozen,smaller ones), things get much tighter maneuvering between trees, etc. in the back yard area, which could probably be done with a small tow behind spreader.

Any suggestion on how slow I should go, what to plan for a target for year one, etc

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You might be careful adding too much dolomite. You can go over the amount of Mg you need.

MAP is more acidic than DAP. I only mentioned MAP because I didn’t know how much acreage you were fertilizing, and assumed it was a smaller backyard planting. Around here they sell MAP in bags, but DAP in bulk. If you are looking at 4-5 acres (which you mentioned liming) I would go with DAP. If you are fertilizing a much smaller area than you are liming, I would got with whatever product you can get in bags. When I initially fertilized my yard (an acre) it was very low in P and required a lot of P and a fair amount of K. I went to the local coop and filled the bed of my pickup with DAP and potash. Then I spread it with a tow behind lawnmower spreader. I also mixed in some other stuff like B and Zn.

I’ve spread fertilizer at the farm both from pickup loads (by hand) and rented a PTO buggy from the coop. If you have a too small an area fertilizing, you may not be able to get the coop out with a fertilizer truck.

As far as how fast to bring the soil up, I don’t know the sensitivities of all the plants you are growing. In terms of liming, they say not to lime more than 2.5 tons per acre per year if the lime is applied as a top dress. In terms of adding K, I think you’d be OK to add quite a bit if your source is potassium nitrate (as long as you don’t overdo the N). If it’s KCl, then I’m not sure how much chloride your various trees/plants can take. In my soil, I’ve added a couple hundred pounds/acre of KCl at once, but my soil has a high CEC, and is fairly dense.

We did kill some new trees once when my son (misunderstanding my instructions) put handfuls of KCL at the base of new trees before a heavy rain, which washed the salts right down to the roots.

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First of all, I’m a soil student, not an expert. Second, I really only have first hand familiarity with Morgan and Melich III soil tests so take my recommendations with a grain of salt.

No matter how “bad” or “poor” a soil looks on paper the proof is in the pudding, but I think any soil can be improved by judicious attempts at balancing it. As you raise your pH and your mineral additions are metabolized by the soil you may get considerably different readings in a year or two. I assume you have a very low CEC along with relatively high rainfall which makes it hard to hang onto nutrients (Did they provide your CEC or TCEC values??). This is a strong case for increasing organic matter OM - compost or composted chicken manure are good sources (as is a thick layer of mulch around your trees - I prefer wood chips). Also, if you mow the grass, try not bagging and let it lay in place, probably best to let it grow longer and cut it higher to maximize organic matter production.

For Ca, I agree dolomitic limestone is the way to go since you’re very low on Mg as well, but since you can only add so much dolomite before it raises your pH above 6.5, consider using Gypsum (Calcium sulfate) to make up the rest since it won’t affect pH.

Soft Rock Phosphate (SRP) is another pretty affordable source of P if you can find some locally and it won’t lower your pH. It also contains lots of other trace minerals and calcium. Phos takes a while to become available to plants. You shouldn’t add more than 175# per acre per year of actual P (SRP is ~20-23% P).

You might consider the sulfate versions of the trace minerals like Cu and Zn. You can buy smaller quantities online for relatively cheap, though maybe you need big bags for that acreage. I would certainly consult your county extension to see if they can provide additional suggestions since they know the local soils.

Cheers!

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No CEC’s reported on the soil report, I briefly went by the local fertilizer place, talked to my step cousin there for a minute, showed him the soil report, and he suggested a custom blend they sell in 50 pound sacks that were made up for local pecan orchards to use around the fruit tree plantings. Unfortunately I had an emergency phone call and had to rush away before getting too many details on the blend, though I do know it was Nitrogen heavy, and did also contain a source of Magnesium, but did not get a chance to write down the exact NPK values.

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I wonder why you are making it this complicated if you aren’t trying to grow fruit commercially. Fruit trees are very adaptable and don’t need a perfect balance of nutrients to be productive although maximum productivity requires some fine tuning. I manage very productive apple trees in soils with a pH in the low 5’s. Sometimes clients don’t let me lime if they are satisfied with the production of the trees. You will likely have no deficiencies if you give them a couple handfuls of urea in spring and mulch them with wood chips (which have available nutrients of everything trees require besides enough N.). Wood chips not only supply massive amounts of potassium but make it easy for trees to absorb it. Compost would solve any CEC issues- wood chips would also, in time.

This isn’t rocket science. It becomes so, when you are needing to get maximum productivity to make a profit. Then it is leaf analysis where you get most of your info.

I’m not saying not to lime or not to do anything in particular, but don’t worry too much about doing it just right.

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Very well put Allen .

I also like the comments of others about fine tuning.

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Sorry about the delay getting back, had a minor family emergency here.

As to my reasoning, I am mostly concerned about improving survival rates, and not having stunted growth in the 20+ young Peach, Asian Pear, Plum, Pluot, etc. trees that I am in the process of adding over the last couple of years. As well as maintaining the overall viability of the other mature trees, grass, etc. as excluding the spot fertilizer applications there has been nothing added to the vast majority of the yard in over a decade.

I did receive some additional test results today, not sure why they were delayed, but here they go:

Copper 0.18 ppm
Iron 70.19 ppm
Manganese 3.49
Zinc 0.52

Aluminum 2.93

on the un-augmented sample
Sample from the blueberry plot showed MUCH higher Iron 170 ppm and MUCH higher Aluminum 39 ppm
I suspect the Aluminum was from the soil mixed in from the nursery pots, though given that was a minority of the sample material it has me concerned about potential Aluminum toxicity. (I have not knowingly added any Aluminum and have avoided Aluminum based fertilizer on the blueberries)

(Numbers including iron were similar to the above on the augmented Citrus plot sample, all numbers were slightly higher as one might expect from fertilizer addition)

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Isaac,

As you probably know, iron is very high.

Zn is low. Again I would recommended adding Zn.

Mn is a little low, but probably OK considering the acidity of the soil.

Cu is low, but personally I don’t worry about Cu (at least for peaches). Sprays for leaf curl and/or bac. spot add more than enough Cu to the soil. In fact, over time excess soil Cu is more often the norm because of sprays.

I don’t know if you have seen this chart, but it gives some relative baselines for nutrient availability at different levels of pH.

http://ptrpest.com/pdf/phnutrients.pdf

It doesn’t mention Al on the chart, but as you are probably aware, Al absorption increases significantly with acidic soils.

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One other resource you might be interested in is this 2015 Fruit Tree Guide. It’s for New England, and I realize you aren’t in New England, but there is some good basic info on nutrient management (page 117).

I only keep offering info/suggestions because you seem very serious about nutrient management, as I was when I started with my first trees.

For those with that level of interest, it’s standard practice to raise soil deficiencies based on soil tests from a soil density basis when starting a new orchard, as the soil section in this fruit guide points out. This is the current practice for commercial orchard establishment. So you are on the right track there (as one with the level of interest you’ve shown) with the exception that an orchard consultant would tell you to incorporate the soil amendments before planting.

As your trees grow, if you still want to manage with a high level of management, the next step would be leaf analysis. It’s not any harder than soil analysis (maybe a little harder) and will tell you exactly what the trees are absorbing. I use A&L labs for both soil and leaf analysis. The costs are fairly minimal.

Admittedly, I haven’t done soil or leaf analysis for a few years. I’ve been a little lazy on that point. But my soil has a high CEC (20 meq/100g) so it doesn’t change much. It’s also “corn soil” so fairly packed with nutrients. In addition, I use organic mulches which add more nutrients than I’m removing. The downside is that our soil drains poorly and holds more moisture than I’d like during rainy periods.

Here is the Fruit Guide:

http://fruit.umext.umass.edu/tfruit/2015netfmg/2015NETreeFruit.pdf

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It’s Cornell’s guide, but they make you pay for it.

Incidentally, I would wager that the majority of commercial producers are not all that precise- the ones I know are more reactive than proactive. If yields fall they start looking for reasons. But the ones I’ve known are relatively small- I would expect margins are watched more carefully when your densely planted acreage is in the 100’s and you are wholesaling against west-coast competition. The growers I’ve known mostly sell from their own stores. Usually they don’t even prune for max production.