#1. Your garden spot was a gun range during it's previous
life.

#2. Start with amendments aimed (pun intended) at
reducing trace poisioning.

This is interesting.

It seems the garden has been heavily amended with lime treated manures given the pH and nutrient content. Manures are commonly treated with lime to speed breakdown and kill the "smell" of it before the home gardener gets a hold of it. If it was not lime treated, the mineral portion of the soil holds the excessive pH part of the equation.

The EC and sodium levels are in the mid-range of over-abundance, but not dangerous for most crops.

There is most likely a pH influenced restriction and/or a competition of some nutrients (which can lead to nutrient exclusion) going on based on the high pH and over abundance of nutrients. All of the nutrients are in such a huge state of abundance that enough to "get the job done" might be available depending on the soil components...which I don't know aside from the 25% organic matter, so it might be an issue or it might not be an issue. This is the only "smoking gun" I can really lay on, but not knowing how much of the nutrients are tied up as unavailable is an issue.

The high pH needs addressing, but the soil needs leeching before tipping a point where that excessive amount of nutrients become pH available once lowered occurs. You run into more/new problems for some crops if that's not addressed. It doesn't need a huge amount of leeching, but it will probably help things over time once the pH is lowered enough to make more of the tied up nutrients more available in the soil solution.

...unless there's some curveballs like soil physical properties (water retention/compaction/etc), weather, or disease (especially fungal wilts) thrown in...*shrug*

I have no idea how to hands-down 100% "fix" it because I'm not sure I've nailed down what's wrong. It would be nice to know what's going on with the mineral portion of the soil, especially as far as the excessive nutrient and pH influence issues go.

I look forward to the solution.

I know what I'd do (and a lot of it is spelled out here), but I feel like I'm overlooking something. I have a high suspicion that pH influenced restriction of plant available nutrients and/or competition from an over abundance of nutrients for exchange sites in the plant is going on, but that's something that's hard to tell based on a soil report. Nutrient competition when there's so much across the board high levels in a high pH soil makes things complex when you don't know what you're working with as far as the mineral portion of the soil.

-edited for final paragraph breakdown to pull my ranting together-

This post was edited by nc-crn on Fri, Jul 19, 13 at 3:37

Since no history of what went into this soil making an assumption that part of the problem is from adding lime treated manure does not follow simple logic. The soil pH is high and that can interfere with plant nutrient uptake as well as utilization. The amount of organic matter in the soil may be causing too much moisture retention which can also interfere with a plants ability to uptake nutrients. There is a good possibility that the Calcium to Magnesium ratio is out of wack and needs adjustment, also.

Too much manure in the past, obviously. Gigantic nutrient levels and off scale OM. I could vote iron deficiency induced by pH, but why are nitrates at zero? Does this bed get any supplemental nitrogen? It seems to me that it should. Long term, the first thing to do is to fertilize with urea only, for many years.

Following the manure theory, maybe there was a lot of uncomposted browns that came in with it, which depleted nitrogen.

I noticed boron was well over the minimum, but I'm not sure at what point it becomes toxic.

After typing this out I saw how long it was. Whew.

For our area soil pH of 7.5-8.0 is pretty typical. Our water is very hard and has a pH of 8.0 with 215-220 ppm of bicarbonate/carbonate. The K, Ca, Mg and S levels are all typical for our soils. The micros are a high from what is usually seen, but none are at levels of concern.The B is really high, but probably not at the toxic level (so long as it doesn't go much higher). As for N, seeing zero or at best very low levels of nitrate N in our soils if there is any appreciable amount of OM in that soil during the summer months is not unusual (every sample I've submitted over the last 20 years comes back in the range of 0-3 ppm nitrate N).

The main issue is excessive P. Our base clay soils tend to hold and accumulate P really well, but typical levels are 100-150 ppm. Anything over 150 begins to become a problem, and by 300 ppm it's becoming a significant problem. My garden soil is showing 313 ppm P. Here's how it got there.

The base soil is sandy loam taken off of local rice fields. After years of flooding/draining the fields build up a top layer deposited from the flood waters over top of the base blackland clay soil. The farmers will at times remove and offer it as topsoil. It is typically ~60-65% sand, 15% clay, balance silt, and basically zero OM. The base mineral nutrient levels (Ca, K, Mg, S) are pretty much what's shown in my test. P is usually in the 75-100 ppm range.

That sandy loam base was blended with 40 volume % of a wood-based compost, no manure added. That typically leaves the mix with ~20% OM. As plants grow I regularly mulch with a coarse but mature compost. Immediately before taking the samples for testing, the mulch layer (~ 1.5") was admixed in with the top 4-6 inches of the soil. Sample depth was 6-8". The combination of the original OM, which I estimate had declined to ~ 16%, plus the turned in mulch led to the apparent OM of 25% in the composite sample.

To 6 yards of that I added 350 lbs of composted cow manure in early March. There was no lime added to the manure at any point. The manure analysis is 0.5-0.5-0.5. The idea was to add enough organic N to get through the first growing season of ~ 6 months, which would be ~ 1.5 lbs N in a 200 sq ft bed. I added 1.75 lbs of N via the manure. So far, so good.

What I failed to take into account was I also added 1.75 lbs of P (and K too). That 1.75 lbs of P in 200 sq ft translates to ~190 ppm of P added. With that added on top of the base P, I ended up way too high. I'm kicking myself for not thinking about the P component, because I've dealt with this on our base soils for years (I learned to stay away from P-containing fertilizers for turfgrass because of our soil accumulation issue). So it ended up where it is because I failed to consider everything that was going into the soil - in this case the P that came with the composted manure.

After a good discussion with the Aggies, I learned a few things about our soils, nutrients, and plant response of which I was not aware. The high micro levels are likely a result of the high OM level broadly, probably came with the compost, but are not a concern. The elevated B level comes from the riceland soils. While it is moderately mobile it tends to accumulate in rice field due to the flooding. It should drop to more normal levels with normal irrigation and drainage.

So what's the problem with very high P? I had been under the impression that the issue was that high P largely sequestered the micro elements into insoluble or immobile compounds that weren't plant available. According to the Aggie docs, in our soils that's really not the issue, and adding more micros, even chelated forms, won't help. According to them plants growing in very high P soils loose their ability to translocate Fe and Zn from the roots to the leaves. It is a plant physiology issue, not really a soil chemistry. The immediate solution is foliar feeding of chelated Fe, and Zn. Adding more to the soil, even chelated, doesn't help much - there is plenty available from the soil, plants take it into the roots, but the plant can't move it to the leaves.

Having faced something similar, but not this extreme, about 10 years ago with previous landscape plantings I suspected that high P might be the issue. Once the chlorosis began to show in select plants I started a foliar feed with EDTA chelated iron in early May. The response was near immediate. At that time I had four new cuke vines emerging, so I did a test - I regularly treated 2 of them with the foliar iron treatment at ~ 10 day intervals, and left the remaining 2 untouched. The difference was dramatic. The treated ones grew full size and produced large cukes, just fewer of them than I would have expected. The untreated ones never got more than 10-12" tall, never flowered, and just sat there as if dormant.

So the plan - first is be sure there is NO P being added at all, and expect that to continue for at least 5 years (and maybe longer). Second is plan regular foliar feedings with chelated micros weekly for all new growing plants, and biweekly for full size and fruiting plants. Third is try to get the pH A few key lessons I (re)learned -- when adding organic materials to the soil be well aware of what you're actually adding, and be sure you want everything that's being added. Soil test are extremely useful, but you also need to know how to interpret them for your soil type and situation It would be very easy to look at the test results above and zero in on N and pH. But those levels aren't indicative of the problem at all, and in fact they are very normal for my soils and situation - it's consistent with about every sample/test I've seen over the last near 20 years.

edit - I forgot to mention probably the largest immediate corrective step taken for the current high P situation. Since this is a raised bed and the soil level had subsided, in part from OM material loss as summer's heat wears on, I added 1 more yard of sandy loam to the bed. This will serve as a bit of a bulk diluent for what's already present.

This post was edited by TXEB on Fri, Jul 19, 13 at 13:33

dang, I don't check in for a few days and I miss all the fun.

That Boron level looks like it could cause some problems with highly susceptible plants like berries. Are you growing any and have they shown any signs of toxicity?

nil - no berries. What little I've seen indicates that in sensitive pants the threshold level for toxic effects is ~10 ppm. According to the Aggie guru, unless I add something with B in it, I should see the levels decline noticeably over the next year with regular irrigation or rainfall.

"Since no history of what went into this soil making an assumption that part of the problem is from adding lime treated manure does not follow simple logic."

The pH + iron, manganese, and sodium levels point to this...so do the Ca, S, and Zn, but they're not as strong of indicators as the pH/Fe/Mn/Na. Ca isn't a solid indicator because it can be given in multiple composted sources, but it generally is found in higher amounts in conjunction with the other high levels of nutrients.

Manures have a "fingerprint" of sorts in a soil test.

Lime is also added to almost any manure pile on the farmer end in order to speed breakdown + kill the smell of the manure pile. This is more common with pig/steer manures. This isn't done to every pile, though.

This post was edited by nc-crn on Fri, Jul 19, 13 at 19:55

nc-crn,

I agree with your assessment based on the numbers. The Ca level is very high if you're not familiar with our soils. I went through that as a shocker when I moved here from MI ~ 20 years ago.

Because of your suspicion I asked the manure folks today who it comes from, and they assured me that they add nothing, nor do the farmers. They contract with large dairy farms, and do the composting on farm site in windrows. They state, with authority, that they add nothing but water when it's needed, and move the compost off site after it's done for packaging. Their word is it 's what came out of the cow, with moisture added as needed, and nothing else.

Our Pledger series soil is noted for it's high natural Ca content. The stated range in the series description is 1-3 % Ca. That would yield 4,000-12,000 ppm Ca in our regional base clay soils. I've never seen anything over 6,000 ppm, but the ~5,400 ppm level is quite normal here.

To put the levels of some of the elements into perspective, I irrigate with our city municipal water. It's surface water and travels the same surface waterways that feed many of our regional rice fields. From our latest public Water Quality Report here are the average levels for the elements/ions noted in the treated water:

pH = 8.0
bicarbonate =215 ppm
carbonate = 8 ppm
Manganese = 12 ppm
Sodium = 87 ppm
Sulfate = 46 ppm

The sodium (and chloride) levels will fluctuate significantly with season and rainfall - we are in a coastal tidal zone, and just 12 miles upstream from a large saline pool with a level of 35,000 ppm.

Wow, such a strange problem to have from my perspective: massive nutrient overdose.

pat - welcome to the world of calcerous, alkaline clay soils, where things tend to stick around. Actually, the only thing that's "overdosed" is P.

Interesting. The iron blocking is due to the combination of high pH and high P.

Well, according to the TAMU experts, the poor iron (and zinc) utilization by plants is due to high P. As it was explained to me, the plant actually absorbs enough iron in its roots, but because of the high P the plant can't translocate the iron to the leaves, where it is needed. That's why foliar feeds work so well. Next time I bump into a plant physiologist I'm going to ask him/her to explain the mechanism to me.

They also tell me at my pH (7.8) and iron levels (13 ppm), there is plenty available, even with the high P. It's just that the plant can't move it from the roots. That's why boosting soil levels of iron or zinc, even as a mobile chelate, won't do much of anything. They tell me that at our typical pH levels (7.5-8) that so long as I have > 4.25 ppm iron, the plant should be able to absorb what it needs.

Plants uptake nutrients/compounds based on size/charge when passing from the soil solution to the root and then into the plant.

PO4 and Fe compete for these uptake sites, and PO4 generally wins, therefore excessive available P outcompetes FE for uptake.

To a lesser, but notable extent, this also happens with Zn and and occasionally Ca (and Al, Mo, etc).

nc - btw, you had it right on the source of the problem (manure), if you allow for the fact that our soils naturally come with the lime already added.

I'm still confused about the uptake/translocation issue. Maybe I misunderstood, but it was my impression that if I had done tissue analysis of both root and leaf, I would have found plenty of iron in the roots, but a deficiency in the leaf. Is that right, or did I misunderstand?

That may be the case...whole plant physiology on the scale of nutrient competition isn't something I'm as knowledgeable about as compared to soil/plant interaction.

While I do know a bit about what happens in the plant with nutrient uptake, I don't know much about nutrient competition in plant tissues compared to what I know about what the nutrients, themselves, do in plant tissues.

My question is: they (Fe and P) compete for the sites, and P wins, but that must happen at the particular, alkaline pH. I doubt that P would win at the place where I had my previous garden, where the soil had a pH of 5.5 (before amending).